Mineral collection: May 2023 haul

Fig. 1 - All the new specimens from the fair: From left to right, azurite+malachite and aragonite (top), cactus amethyst, vanadinite, chrome diopside, fluorite and cinnabar (bottom).

 Fourth post in my new mineralogy series, talking about my mineral collection ✨💎! This time it's not another installment about the specimens from the National Geographic RBA minerals collection that I've been getting since 2022 (more of that specific series to come after this haul!), but rather about the new (and gorgeous) specimens that I got at a local fair this past May, from a mineral stall (@/cabolitos on Instagram) - Featuring (see Fig. 1) azurite+malachite, aragonite, vanadinite, fluorite, cactus amethyst/'ametrine', chrome diopside, and cinnabar (mercury sulfide). These are easily among the most stunning specimens in my collection, all of them are so beautiful 😍, and lately I'd been especially looking for a larger azurite specimen and a vanadinite (I got another one at another September fair since), so yay 😁👌!

Here's a video with all of the minerals from this haul (also on TikTok, and a slideshow post here as well). See below for the individual videos!

And before the haul, here are some pictures of the mineral stall from the fair, and it was mineralogy heaven, so many beautiful specimens  ✨💎! I was also pleasantly surprised by this stall because the main section of it was revolving around mineralogy and mineral collecting per se, with most minerals organized in your typical cardboard and methacrylate boxes indicating the name and country of origin of each specimen. Typically, stalls at local fairs which sell gems and minerals tend to be mainly focused on the New Age/'crystal healing'/esoteric/spiritual aspects (see this post to see why 'crystal healing' is such a huge pet peeve of mine 😅), so yeah, big breath of fresh air, honestly! And while I also do like tumbled stones and polished minerals and gems, this stall also offered a lot more rough/unpolished specimens than is also typical among fair stalls in my area, so I really liked that as well 😃. 

Fig. 2 - This mineral stall was mineralogy heaven ✨💎!

Fig. 3 - So many minerals ✨💎!

Fig. 4 - No fair outing is an optimum fair outing without some chips xD!

 

 A hefty picture spam is incoming 🤩💎 and will be the main highlight of this post, but I'll also be expanding on some of these minerals, namely the cactus amethyst variety, and cinnabar (and mercury), which won't feature in the National Geographic/RBA collection posts. For the rest, malachite, aragonite, vanadinite and (chrome) diopside will feature in future installments of the RBA series, and I have already talked about the remaining ones in the following posts:

✨Post 1: Amethyst (with general mentions to ametrine) and fluorite.

✨Post 3: Azurite (with general mention to malachite).

 So, let's being with the pic spam 😃✨:

Fig. 5 - From left to right: Azurite+malachite and aragonite (top), cactus amethyst
and vanadinite (bottom).

Fig. 6 - From left to right: Aragonite (top), chrome diopside, cinnabar, fluorite (bottom).

Fig. 7 - These were the minerals that I got on my first outing, then the next day I also got the aragonite and vanadinite xD. From top to bottom, left to right: Azurite+malachite, cactus amethyst, cinnabar, fluorite and chrome diopside.

 

1) Azurite & malachite:  

This large azurite and malachite specimen over a goethite matrix plate is absolutely gorgeous, and easily one of my top 5 fave specimens in my collection 😍💎. The front is nearly completely covered with patches of deep blue azurite, accompanied by some bright green malachite patinas at the right, while the back and sides feature small crystals of both azurite and malachite strewned upon the goethite plate. Also, see below for a couple of videos showcasing the rich colour and glittering crystals of my large azurite specimen ✨:

✨Read more about azurite in this post from my RBA mineral collection series.

Fig. 8 - Look at this beauty 😍! Azurite+malachite on a goethite matrix plate, front view.

Fig. 9 - Azurite+malachite on a goethite matrix plate, side and back view.

Fig. 10 - Azurite+malachite, front, II.

Fig. 11 - Azurite+malachite, size comparison with hand.

Fig. 12 - Azurite+malachite, front view, III.

Fig. 13 - Azurite+malachite (top), alongside cactus amethyst and vanadinite (bottom).

Fig. 14 - Azurite+malachite (left), alongside amethyst and celestine cluster.

  Videos ✨ (also on TikTok here and here, and slideshow post here as well):

 2) Aragonite: 

This large aragonite cluster, originating from Tichka (Morocco), shows a beautiful display of red, reddish-brown and white pseudo-hexagonal prismatic crystals of varying sizes, grouped around a central axis - These kind of specimens are typically called 'pinecone aragonite' or 'aragonite star clusters'. Also see a couple of videos below showing the different colour hues of this lovely cluster and the shape and vitreous luster of its crystals✨.

 ✨Aragonite will feature in the upcoming post 4 of the RBA mineral collection series on this blog.

Fig. 15 - Aragonite star cluster from the fair (front view), with other aragonite specimens from my collection in the background.

Fig. 16 - Aragonite star cluster (side).

Fig. 17 - Aragonite star cluster (back).

Fig. 18 - Look at how pretty the crystals are in this specimen! Aragonite star cluster in direct sunlight (front view, size comparison with hand).

Fig. 19 - Aragonite star cluster in direct sunlight (back, size comparison with hand).

Fig. 20 - Aragonite star cluster (front view, comparison with hand).

Fig. 21 - Aragonite star cluster (side).

Fig. 22 - Aragonite star cluster (front view, comparison with hand).

 Video ✨ (also on TikTok here, and slideshow post also here):

3) Cactus amethyst: 

Alongside the gorgeous azurite+malachite and vanadinite specimens in this haul (all of the minerals in this haul are gorgeous, really, but I was most excited about finally finding some nice specimens of these two, as I said above), I was particularly thrilled to also find some cactus amethysts in the mineral stall - and this is quite a beautiful specimen, showcasing both the purple hues of amethyst in the terminations of the main (pyramidal prismatic) crystals and in all of the smaller crystals, and the intense orange-yellow hues inside the main crystals, caused by iron oxide inclusions (but not citrine, see below) 😍💎. As we will see below when discussing ametrine, we could also refer to this cactus amethyst specimen (as shown in Figs. 23-27) as a 'cactus ametrine' (although bearing in mind that 'ametrine' is the trade name, and the most recent studies seem to show that the yellow zones of ametrine are caused by iron oxide inclusions, rather than being citrine quartz - see below).

Scroll down the (lovely) picture spam for a video showing the showy colours and shine of the multiple quartz crystals in this piece, as well as for some general information and trivia about both cactus quartz and ametrine ✨:

Fig. 23 - A stunner 😍! Cactus amethyst with yellow iron oxide inclusions, front view and size comparison with hand.

Fig. 24 - Cactus amethyst, with azurite+malachite in the background.

Fig. 25 - Cactus amethyst, with azurite+malachite in the background.

Fig. 26 - Cactus amethyst, front view. The iron-stained orange-yellow zones in the middle of the prisms contrast in a beautiful way with the pale violet hues of the amethyst in the crystal terminations and in the smaller crystals all around the main ones.

Fig. 27 - Cactus amethyst, with azurite+malachite in the background. The colours are particularly intense here.

Video ✨ (also on TikTok here, and slideshow post also here): 

💎A bit about cactus amethyst and ametrine: Source 1,  Source 2,  Source 3, Source 4, Source 5, Source 6, Source 7

 ✨Read more about amethyst (with a brief mention to ametrine) in Post 1 of my RBA mineral collection series. Citrine (both natural and heated) will feature in a future post of the RBA collection as well.

 

 The cactus quartz variety, also known as 'pineapple quartz' and 'spirit quartz', is so rare as to be practically only to be found in one place: the Magaliesberg Mountains close to Pretoria (South Africa). It usually occurs as large pyramidal-shaped and perfectly formed quartz crystals, containing multiple twinned quartz crystals with faceted terminations on each hexagonal side of the main prismatic crystal (see Figs. 23-27). The disposition of these smaller crystals is what creates the prickly "cactus" appearance of this variety. Some specimens of cactus quartz are composed only of amethyst, while others can range from clear to smoky and yellow hues caused by iron residue inside the crystals.

Fig. 28 - Inaccurate ametrine infographic (Source).

Various sources have generally defined (and still define, see Fig. 28) 'ametrine' as the resulting bicolour purple+yellow quartz variety which includes both amethyst and citrine zones in the same crystal. Thus, the name originated from the combination of 'amethyst' and 'citrine'. Also called trystine and 'bicolour amethyst', this naturally occurring variety of quartz makes for quite a rare gemstone that is mainly (but not exclusively) produced in commercial quantities in the Anahi mine in Bolivia (thus its trade name bolivianite). 

 

Earlier studies explained the presence of both amethyst and citrine in an ametrine specimen due to differing oxidation states of iron impurities within the crystal, with purple amethyst zones thought to be produced by Fe³⁺ that is oxidized to Fe⁴⁺ as a cause of natural radiation emitted by the decay of potassium-40 in nearby rocks; and the yellow citrine segments being produced by oxidized Fe³⁺ iron. Moreover, these different oxidation states occur due to the presence of a temperature gradient across the crystal during its formation process.

 

However, some studies have actually concluded that amethyst and citrine cannot form in the same environments, and thus 'ametrine' specimens would be instead composed of amethyst with inclusions of iron compounds which create yellow and orange zones reminiscent of citrine (in contrast, the yellow tones in citrine quartz specimens seem to not be simply caused by trace elements in the crystal, and are also at least in part aluminum-based rather than iron-based). Thus, the purple zones in ametrine specimens are indeed made of amethyst, but the yellow segments would be more accurately referred to as 'ferruginous quartz' instead of 'citrine'. Additionally, upon heating ametrine the amethyst zones pale, while the yellow-orange areas maintain their colour (in contrast to citrine quartz, which also pales when heated). Despite this, the trade name to refer to this variety has typically remained 'ametrine'.

 

In view of this, we can refer to this cactus quartz specimen (Figs. 23-27) as either a cactus 'ametrine' (as in combining amethyst with ferruginous quartz zones), or simply as a cactus amethyst which also happens to include some iron-stained orange-yellow zones, in so many words. In any case, the hues in these cactus quartz specimens are completely natural and have not been either dyed or heat-treated, in contrast to the common practice of heat-treating amethyst to obtain affordable 'citrine' specimens (I actually like the intense tones and zoning of some treated citrines, though, I only wish there was way more transparency in the mineral market about it 😅). Moreover, unlike the typically lighter and more homogeneous yellow tones of many natural citrines, cactus 'ametrines' such as this one (which contain iron-stained zones rather than citrine, as we have seen) can feature very intense orange-yellow hues in the middle of the main crystals, due to the sides reflecting the iron-stained hues from underneath.

 

A well-formed ametrine crystal sawn perpendicular to the c-axis (optic axis) can also form a striking geometric pattern radiating outwards from the axis like the pieces of a pie, with straight lines separating the zones of amethyst and ferruginous yellow quartz:

Fig. 29 - Geometric pattern in an ametrine specimen from Anahi mine (Bolivia) (Source).

 ✨Some interesting historical and STEM trivia about ametrine: 

• According to legend, the indigenous Ayoreos tribe of Eastern Bolivia (currently living in an area spanning both Bolivia and Paraguay) knew about the existence of bicolour quartz crystals with zonal colouring of purple and yellow (aka ametrine) over 500 years ago, and it was introduced in Europe in 1600s when a Spanish colonizer ("conquistador") (sighs in Spaniard not happy about the country's colonialist past) gifted the Spanish Queen some ametrine after acquiring a mine in Bolivia as dowry for marrying a princess from the Ayoreos people (doubly sighs in sexism and colonialism). Legend or not, this is not dissimilar to the way that many things (food, cultural, technology, fashion, etc) from America, Africa, Asia and Oceania were introduced to Europe, via colonialism and imperialism (and, in this case, also patriarchy, yay) 😬. But the earliest attested mention of ametrine in Europe was probably in a 1925 issue of American Mineralogist, with further reports beginning in earnest in the 1960s and ametrine becoming more available in the 1970s.
  

• Synthetic ametrine: Heat and irradiation can be used to transform natural amethyst into a bicolour material similar to ametrine, as determined in laboratory experiments as early as 1981, but this process is very costly and has seemingly not produced appreciable quantities of synthetic 'ametrine'. With many similarities (but also differences) to their natural counterparts in Bolivia, gem-quality synthetic ametrine has been produced in Russia since 1994, via hydrothermal synthesis from alkaline solutions, followed by irradiation of the created crystals.
  

4) Vanadinite: 

This stunning specimen of vanadinite, originating from Mibladen (Morocco), definitely comes in second among my favourites, after the azurite+malachite piece (with the aragonite and cactus ametrine closely viyng for third position). It displays a cluster of gorgeous bright orange-red crystals on a matrix plate 😍💎. The vanadinite crystals in this specimen come in varying sizes, with the largest of them clearly displaying their hexagonal (prismatic) shape. I especially love one of the largest hexagonal-shaped crystals sticking out at the side! Also see the video below showcasing the rich colour and the characteristic adamantine luster of these vanadinite crystals ✨.

 ✨Vanadinite will feature in an upcoming post of the RBA mineral collection series on this blog.

Fig. 30 -  Rich colours and sparkles ahoy 😍! Vanadinite cluster with bright orange-red crystals, front view. Another vanadinite specimen in my collection can be seen in the background, featuring darker-coloured cyrstals.

Fig. 31 -  Vanadinite cluster with bright orange-red hexagonal prismatic crystals, side views. Note the largest hexagonal crystal sticking out at the side!

Fig. 32 - Vanadinite cluster, more details.

Fig. 33  -  Vanadinite cluster, from above, with another vanadinite specimen in the background.

Video ✨ (also on TikTok here, and slideshow post also here):

5) Chrome diopside: 

This chrome diopside specimen, a lovely rich green prismatic crystal, originates from Nuristan (Afghanistan), and includes some white quartz inclusions, especially on one side. See a video below featuring the vibrant green of this diopside in direct sunlight!

 ✨(Chrome) diopside will feature in an upcoming post of the RBA mineral collection series on this blog.

Fig. 34  -  This chrome diopside prismatic crystal has a lovely rich green colour, reminiscent of other bright green gems like peridotite.

Fig. 35 -  The chromium in this diopside crystal is what gives it its rich green colour.

✨Video  (also on TikTok here, and slideshow post also here):

 

 6) Fluorite:  

I also got this small tumbled fluorite as a gift, and it's a lovely one, displaying a very defined banding pattern with various hues of green and purple.

✨Read more about fluorite in this post from my RBA mineral collection series on this blog. 

 

Fig. 36 -  This tumbled fluorite showcases a very defined banding pattern in various shades of green and purple.

Fig. 37 -  Tumbled fluorite with a very defined banding pattern, size comparison with hand.

Fig. 38 - The polished fluorite from the fair alongside the rough specimen from the RBA collection.

Fig. 39 - The polished fluorite from the fair alongside the rough specimen from the RBA collection.

 

 ✨Video  (also on TikTok here, and slideshow post also here): 

 

 

7) Cinnabar (and mercury):  

And finally, I also got a small specimen of cinnabar with mercury (Figs. 40-43), from Almadén (Ciudad Real, Spain), featuring its characteristic rich deep red hue alongside some silvery grey-black parts, as well as a very pretty shimmer in the light due to the tiny native mercury drops present in the specimen. In my existing collection, I already had some mercury in a bottle (see Figs. 40 and 44), also from Almadén, which I got quite a few years ago (I don't think they sell native mercury as often now for safety reasons). 

Important note: Cinnabar and mercury are toxic minerals 😅. Collecting cinnabar specimens should be reasonably safe if handled correctly, but don't keep liquid mercury out of its bottle or container (it's dangerous to touch and especially to inhale). In contrast to native mercury, cinnabar is insoluble and more stable than native mercury, but it's a very good idea to wear gloves when handling cinnabar, and/or to wash one's hands after touching a cinnabar specimen (especially the specimens which include native mercury in them, typically those with a massive habit). Even though in the pictures I appear holding cinnabar bare-handed, it was for a very short period of time, and I washed my hands immediately afterwards! In fact, it's standard advice among the mineralogy collecting community to wash one's hands after handling *any* mineral, just in case (as well as keeping the minerals away from children and pets, not licking or ingesting them, and not inhaling any mineral powder). Finally, although some people display their cinnabar specimens more in the open in a display case or specimen cabinet with reasonable safety, I personally like to keep mine inside a closed box alongside other specimens, and only take it out for short periods of time when needed.

Scroll down this picture spam for a couple of videos showing both the red hue and glimmer of this cinnabar specimen, and how liquid mercury moves. And then we'll finish this post with some general information and trivia about cinnabar and mercury ✨:

Fig. 40 - Cinnabar in massive habit with native mercury (left), alongside native mercury (right).

Fig. 41 - Cinnabar with native mercury (front).

Fig. 42 - Cinnabar with native mercury (front and side).

Fig. 43 - Cinnabar with native mercury (back and side).

Fig. 44 - Native mercury in bottle.

 

✨Infographic video (also on TikTok here, and slideshow post also here):

 💎A bit about cinnabar and mercury: Source 1,  Source 2,  Source 3, Source 4, Source 5

 

Fig. 45 - Cinnabar infographic (Source)

- Cinnabar (also called cinnabarite) is a toxic mineral with a chemical composition of HgS (mercury(II) sulfide), the most important and common ore of elemental mercury (Hg). A hydrothermal mineral associated with recent volcanic activity, as well as hot springs and fumaroles, cinnabar typically precipitates at shallow depths as coatings on rock surfaces and as vein fillings from ascending hot vapors and waters moving through fractured rocks. 

 

Cinnabar is mostly associated with native mercury, as well as with other sulfide minerals, such as pyrite, realgar, marcasite and stibnite, and is typically found alongside gangue minerals (materials surrounding a deposit ore) which include quartz, barite, dolomite and calcite. The most important cinnabar deposit worldwide for centuries has been Almadén, in Ciudad Real (Spain), exploited since Roman times, from where both the specimens above originate.

Cinnabar typically ranges from bright scarlet to brick red in colour, and is generally found in a massive or granular habit, sometimes with small droplets of liquid mercury also present on or near the specimen (as is the case in my specimen). Sometimes, a silver colouration can also be seen on cinnabar, a product of colloidal mercury being formed on the crystal surface after photo-oxidation. Cinnabar can also occasionally occur as well-formed prismatic crystals with an adamantine luster, ressembling quartz in symmetry and exhibiting the phenomenon of birefringence, with the second highest refractive index of any mineral.

 

- Mercury (also known as quicksilver, with symbol Hg) is a heavy and silvery-white chemical element, the only metal which remains liquid at standard temperature and pressure. Extremely rare in Earth's crust as a native metal (although large liquid masses have been found in rock cavities), mercury typically occurs in volcanic regions and hot spring deposits worldwide mostly as cinnabar, and can be also associated with other ores, such as sphalerite and corderoite. In spite of being liquid, and thus not satisfying the normal criteria to be classified as a mineral (it only forms rhombohedral crystals at -40 degrees celsius), mercury is officially classed as a mineral species because of its distinctive chemical and physical properties, as well as for historical reasons.

 ✨Some interesting historical and STEM trivia about cinnabar and mercury:  

• The etymology of cinnabar: The origin of the name "cinnabar" comes from Ancient Greek κιννάβαρι (kinnàbari), cited by Theophrastus (c. 371 – c. 287 BC) in his treatise Περὶ λίθων (On Stones). The origin of this word is oriental in origin, associated with Persian zinjirfrah and Arabic zinjafr, "Dragon's blood".

• The etymology of mercury: The chemical symbol "Hg" is an abbreviation of hydrargyrum, a romanized form of the ancient Greek name for mercury, ὑδράργυρος (hydrargyros) "water-silver", from hydro "water" and argyros "silver" (so called, similarly to 'quicksilver' "living-silver", due to the element's liquid, shiny aspect). On the other hand, mercury is the only metal for which its alchemical planetary name survives as one of its current common names. In Medieval alchemy, the then seven known planets gave their name to the seven known metals (quicksilver, gold, silver, copper, iron, lead, tin). Quicksilver was associated with the fastest planet, Mercury, named after the Roman name for Hermes, the wing-sandaled messenger of the gods in Ancient Greece.
  

Fig. 46 - Apparatus for the distillation of mercury from cinnabar, Alchimia, anonymous, 1570.

• Cinnabar as a mercury ore:  Cinnabar has been mined for thousands of years, as far as the Neolithic Age, to obtain mercury. Liquid mercury was produced by crushing cinnabar and heating it in rotary furnaces (see Fig. 46 for an example in a 16th Century book). During the process, mercury separated from sulphur, escaping as a vapour that could be collected and condensed into liquid mercury.

• Decorative uses of cinnabar: Due to its bright red colour, many cultures have used cinnabar for decorative purposes for thousands of years, tracing back to Paleolithic cave paintings in Spain and France from 30,000 years ago. It is also one of the few minerals that have been in use by ancient people worldwide, from the European Mediterranean to the Middle East, Eastern Asia and the Mayan and Incan cultures in South America. Cinnabar was ground into a fine powder and used as a pigment for paints and cosmetics (cinnabar being the historic source of red pigments such as "vermillion" and "Chinese red"), as well as carved into ornaments and jewellery. Chinese lacquerware using cinnabar is especially famous (see Fig. 47 below for an example), a technique dating back to the Song dynasty (960–1279 AD). Due to the toxicity of cinnabar, however, its use in paints, decoration and cosmetics has been discontinued in present times, substituted by safer synthetic alternatives.

Fig. 47 - Chinese cinnabar lacquerware: A Yuan oval tray with people in a landscape. Source.

• Toxicity: Cinnabar is a highly toxic material due to its mercury content, and mercurialism due to overexposure to mercury (which can be both absorbed through the skin and inhaled as vapours) was a disease recognized historically as early as ancient Rome, where cinnabar was already being mined both for pigment and decorative purposes, and for its mercury content. The toxic properties of mercury were also known in other parts of the world, such as ancient South America, where cinnabar was also routinely used for similar purposes. Mining and processing cinnabar was (and is) very dangerous, and many of the workers in the (in)famous mine of Almadén (Spain) were enslaved people and convicts, as working there was regarded as pretty much death sentence, with a considerably shortened life expectancy for the miners, constantly exposed to toxic mercury fumes. Nowadays, there fortunately tend to be stricter protocols when it comes to safely handling mercury and its compounds in the cases when this element continues to be in use (see below), with specific cleaning procedures to avoid exposure in the event of potential mercury spills. Contamination of mercury in the environment (especially in the sea), however, continues to be a pressing problem.

• Mercury in history: Similarly to cinnabar, native mercury has been in use historically for thousands of years worldwide, having been found as far back as 1500 BC in both Egyptian tombs and Mesoamerican pyramids. Despite its high toxicity, it has been used repeteadly for cosmetics and supposed medicinal purposes in various cultures, from ancient Egypt, to ancient Greece and Rome, China and India. Throughout the European Middle Ages and Renaissance period, the use of mercury was still (quite wrongly) thought to maintain good health and promote longevity (on the contrary, exposure to mercury leads to severe adverse health effects 😬). Mercury was also routinely used in the mining industry to create amalgams, alloys of mercury with other metals, and alchemists additionally believed that the different metals could be obtained by varying the quantities of sulphur in mercury, with the ultimate goal of achieving the transmutation of several metals into gold.
  

• Uses of mercury: Despite the many applications of mercury, its high toxicity has resulted in its use being reduced or discontinued whenever possible due to health and safety regulations, and to replace it with less toxic and nontoxic substitutes. Mercury was formerly widely utilized in the manufacture of industrial chemicals and electrical and electronic applications, and has been famously used since the 18th century as a part of temperature- and pressure-measuring instruments such as thermometers and barometers. The use of these instruments declined in the early the 21st century and has been since banned in several countries and medical institutions. Mercury does still remain in use in several scientific research applications, however (for an Astrophysics example, see liquid mirror telescopes below), and gaseous mercury is still utilized in fluorescent lighting. Many more uses of mercury, past and present (many of them dangerous 😅), are listed here, from ancient divination practices, to mercury-filled pools as decoration, skincare products (yikes), gold prospecting and silver mining, as coolant for nuclear reactors, or as propellant for space engines.
  

Fig. 48 - The Liquid Mirror Telescope at the NASA Orbital Debris Observatory in Cloudcroft, New Mexico, operated from 1996 to 2000. Source.

•  🌟🪐Astrophysics fact! Liquid mirror telescopes: For some reflecting transit telescopes (mounted on a horizontal axis), liquid mirrors made out of mercury have been used as the primary mirror since the 1990s (see Fig. 48). These mirrors assume a concave paraboloidal shape by rotating the liquid and its container at a constant speed aroung a vertical axis. The main advantage of such a rotating liquid metal mirror is that they are vastly more affordable than conventional solid glass mirror telescopes, which typically account for at least 95% of the cost of the entire telescope. As for disadvantages, a liquid mirror cannot be tilted and thus always points straight up, which limits their use to zenith telescopes and astronomical fields of research which would remain unaffected by the fact that the mirror's view changes as the Earth rotates and cannot track physical objects (these research fields include long-term sky surveys, supernova searches and some cosmology studies). Another disadvantage is of course once again presented by the toxicity of mercury vapours (with the alternative less toxic metal gallium being considerably more expensive), resulting in the need to house the mirror and the human operators in separate, well-ventilated rooms, as well as placing the telescope in more isolated locations to reduce hazards to the area population.
  

And that's it for this haul! Stay tuned for more mineral content with a next installment of the RBA collection series (or perhaps, another haul) 😁!

Mineral collection: December 2023 haul

Fig. 1 - Small-to-medium-sized rough specimens from the haul: From left to right, top to bottom - Fluorite, lepidolite, blue apatite, and green zoisite with pargasite.

Fig. 2 - Small boxed specimens from the haul: From left to right, top to bottom - Aragonite, rhodonite, rock crystal, green tourmaline with quartz, and hematoid (red) quartz.

    Fifth post in my mineralogy series, talking about my mineral collection ✨💎! This time it's a new haul from December 2023 from a mineral stall at a local mall - Featuring four small to medium-sized pieces (see Fig. 1) - Fluorite, zoisite with pargasite, lepidolite, and blue apatite -, and five small specimens in cardboard boxes: Aragonite, rhodonite, rock crystal (clear quartz), hematoid (red) quartz, and green tourmaline in quartz (see Fig. 2). With this haul I got my first piece with tourmaline crystals; as well as another lepidolite added to my apparent mica subcollection xD; my first zoisite; my largest fluorite specimen so far (and it's a gorgeous one!); my first raw rhodonite; and more quartzs because you can never have too many quartzs, say I 😁👌!

Before an extensive image gallery with all of these new pieces, here are some pictures of the mineral stall ✨💎.  This stall offered quite a variety of minerals, from the most commonly found tumbled stones, quartz geodes and amethyst clusters, jewellery and decorative objects (from pyramids and towers, to trees and other carved objects), to a selection of small mineral specimens in collectors' cardboard boxes (which was a pleasant surprise, I love these), and also some larger rough pieces, including celestine, lepidolite, fluorite, zoisite (mislabelled as 'ruby zoisite', as we'll later see 😅), rose quartz, rock crystal, and blue apatite. The stall vendor was really nice too, letting us browse to our heart's content and giving us a freebie with our haul (the small blue apatite) 😊.

Fig. 3 - The mineral stall, featuring quite a lot of collectors' specimens in cardboard boxes, some rough and carved pieces at the back, and tumbles on the right.

Fig. 4 - Selecting a zoisite, fluorite and lepidolite at the stall!

Fig. 5 - Quite a variety of kinds of minerals at this stall - from small boxed specimens, to rough and carved pieces, pendants, and tumbled stones. Shame about the 'crystal healing' mumbo-jumbo, tho :S

   The only con that I would list about this stall, apart from the mislabelling problems (we'll get to that later), is the unfortunate ubiquitous presence of the 'crystal healing'/esoteric aspects, especially in the areas of the tumbled stones and some of the rough specimens, with labels indicating the supposed 'properties' of each mineral (see this post to see why 'crystal healing' pseudoscience is such a huge pet peeve of mine 😅). And it's such a pet peeve because it isn't just some harmless mumbo-jumbo that people may want to believe in, it can also effectively (and negatively) affect people's decisions regarding their health. While I was browsing, I overheard a couple of university-age women selecting which tumbles to buy, and they weren't deciding based on such harmless criteria as their collections or their preferences as to colour, shape or luster, no. They were chatting about 'crystal healing' pseudoscience as a statement of fact, and one of them was considering getting a hematite tumble because the label said that this iron ore 'helped with anemia' and she had anemia. Girl, please, forget about the hematite and take some iron supplements instead 😬.

 And now, here's for the hefty picture spam, which will be the main highlight of this post, apart from some brief descriptions of each piece 🤩💎. I typically expand on each of the minerals in my collection and show all specimens together in my National Geographic/RBA collection series in this blog (unless any haul minerals happen to not appear on that collection). So, in this case, I'll be expanding on zoisite here, while in future installments of this series I'll be writing in more detail about rock crystal, hematoid/red quartz, lepidolite, apatite, and green tourmaline (verdelite). The rest have already featured in existing posts of the RBA series, as follows:

✨Post 1: Quartz (general introduction), and fluorite.

✨Post 2: General info about the mica group, rhodonite. Also, a section about milky quartz and iron-coated quartz.

 So, let's being with the pic spam, first some pics with all the haul together 😃✨:

Fig. 6 - From left to right, top to bottom: Lepidolite, zoisite and pargasite, fluorite, and blue apatite.

Fig. 7 - The five new boxed specimens: From left to right, top to bottom - Rock crystal, hematoid (red) quartz, green tourmaline with quartz, rhodonite and aragonite. More minerals from my collection in the background, featuring malachite, vanadinite, citrine, amethyst, azurite+malachite, and celestine.

Fig. 8 - Same as Fig. 6, in direct sunlight.

Fig. 9 - One happy mineral collector with her new haul 🤩💎

Fig. 10 - Said haul 💎

Fig. 11 - The boxed minerals. More minerals from my collection in the background, featuring amethyst, lepidolite, labradorite, pyrite, smoky quartz, malachite, vanadinite, citrine, azurite+malachite, and celestine.

Fig. 12 - Same as Fig. 2, with flash.

 ✨Also, a couple of compilation videos with all of these new pieces together (also on TikTok here and here; bonus slideshow post here; and see longer videos for each of them below as well!):

And now for individual pictures of each of these, alongside a brief description ✨:

1) Fluorite: 

   Fluorite (calcium fluoride, CaF₂) is definitely one of my favourite minerals, especially because of its stunning array of colours, a result of impurities and exposure to radiation, tinting the transparent and colourless pure form of fluorite into transparent-to-translucent pieces with banding and/or zoning in various colours (where green, purple, blue and yellow are the most common). My fluorite pieces have (several shades of) green as their main colour, with purple, blue and light pink zoning, and they're especially beautiful to look at against the light, as the picture spam below will amply demonstrate ✨😍 xD. 

✨Read more about fluorite in this post from my RBA mineral collection series on this blog. 

   This is the largest specimen of fluorite in my collection so far (as seen in Fig. 17, alongside all my other fluorites), and it's mostly a translucent light green, alongside a couple of purple zones (especially a larger zone at one tip of the piece), and some cyan blue zoning and even some yellow also appear when looking at it against the light (see Figs. 13-19 below, and also Figs. 1, 4, 6, 8 and 10 above). The banding is not so prominent in this piece in contrast to my tumbled fluorites, but you can also see some more subtle purple and cyan banding patterns against the light. The characteristic vitreous luster of fluorite also creates an iridescent effect on the surface for this particular piece (a result of light reflecting and scattering through layers of crystallization or internal fractures, as seen, for example, in Fig. 15 and the videos below), and it's so pretty to look at! 

See below for pictures and a video showcasing the luster and beautiful colour zoning of this fluorite ✨:

Fig. 13 - The largest fluorite in my collection so far, mostly green with a distinct purple zone.

Fig. 14 - Green and purple fluorite against direct evening sunlight. The subtle cyan zoning in this piece is more noticeable here, close to the purple banding and zoning at the top.

Fig. 15 - This specimen of fluorite showcases a lovely vitreous luster, and also shows some iridescence on the surface at some angles, as a result of the scattering of the incident light by the translucent crystal layers.

Fig. 16 - Green and purple fluorite against direct evening sunlight. The purple banding and zoning at the top is more defined at this angle.

Fig. 17 - Green and purple fluorite against direct evening sunlight.

Fig. 18 - Green and purple fluorite against direct evening sunlight (featuring a rainbow lens flare on the right).

Fig. 19 - My new fluorite (left), alongside the rest of the fluorites in my collection.

✨Video ✨ (also on TikTok here; bonus slideshow post): 

2) Lepidolite: 

This purple mica is very rich in lithium (Li), and the fact that I keep bumping into lepidolite (I have three so far, as pictured in Fig. 19) is extremely funny to me, because my Astrophysics thesis revolved around studying stellar lithium to calibrate open clusters and estimate stellar ages. So every time I find a lepidolite or other mineral containing lithium, it's highly probable that I will get it (see Fig. 21), if only because of the inside joke 🤣. I also really like the colour purple (the book also, but no pun intended xD), so the range of purples of lepidolite (from lilac to grey-violet, a deeper purple or purplish pink) is another thing that I quite like about this mineral 💜.  Lepidolite will also feature in future installments of my RBA mineral collection series!

This is the third lepidolite in my collection (see Figs. 20-23 below, and also Figs. 1, 4, 6, 8 and 10 above), a medium(ish)-sized raw piece featuring a massive habit, its characteristic vitreous-to-pearly luster, and a purple shade that I would describe as lilac-grey, although it does change subtly depending on the lighting (as we can see in the photos, depending on whether there's direct or indirect sunlight, artificial lighting, or camera flash), from a slightly deeper lavender to rosier or more greyish hues.

 

  The video below (in direct sunlight) showcases the  vitreous and sparkly luster typical of this mica variety and the delicate lilac shade of this specific lepidolite, ranging to more greyish hues in the early afternoon Sun to rosier tones in late evening direct sunlight✨:

 

Fig. 20 - A raw lepidolite with a massive habit, here photographing as a rosy lilac-grey.

Fig. 21 - The new lepidolite alongside my other two specimens, featuring a smaller and very pale grey-lilac raw piece, and a deeper purple large slab in the scaly aggregate habit in which many micas are found.

Fig. 22 - More angles for this lepidolite. The very sparkly nature of this specimen doesn't show as well in photos as in video, but these pictures manage to capture it a bit.

Fig. 23 - Showing a deeper lavender in this lighting, with the other two specimens in the background.

✨Video (also on TikTok here; bonus slideshow post): 

3) Blue apatite: 

  I got this small raw specimen of blue apatite (a group of phosphate minerals) as a freebie for the other purchases! This is the second apatite in my collection (the other being the specimen from the RBA collection, see Fig. 25, in the background). It's rather more delicate than my other apatite, as I found out when several small pieces started to break off when I was minimally handling it to take pictures of it 😱 (at least that was a good moment to see the conchoidal to uneven fracture of apatite, I guess 😅 xD). It's still got a very interesting shape despite the breakage accident, though, and displays the characteristic luster that's a mix between vitreous and resinous. As for the colour, the typical peacock blue hue of blue apatite appears a bit more intensely in the RBA collection piece, but this specimen (as pictured in Figs. 24-26 below, as well as in Figs. 1, 6, 8 and 10 above) also showcases its bright blue, which is the highlight of blue apatite for me ✨.

✨Apatite will also feature in future installments of my RBA mineral collection series! Also see below for a video where we can see the luster, colour and shape of this blue apatite, in direct sunlight ✨:

Fig. 24 - A small blue apatite, showcasing its characteristic bright peacock blue hue.

Fig. 25 - The new blue apatite, alongside my other specimen from the RBA collection (in the background). The latter has a slightly brighter blue shade.

Fig. 26 - Different angles of this blue apatite, in direct sunlight.

✨Video (also on TikTok here; bonus slideshow post): 

4) Zoisite & pargasite: 

   This green zoisite (chrome-zoisite) with inclusions of black pargasite (see Figs. 27-28 and 31-33 below, as well as Figs. 1, 4, 6, 8 and 10 above) has a curious story about it. At the stall, it was sold as 'ruby zoisite' 🤔, and right off the bat it was quite clear that there was no ruby going on anywhere in any of these pieces, unless they're so tiny I would need a UV torchlight to identify the rubies via fluorescence, as red corundum aka ruby fluoresces very bright red under UV light (I later confirmed with my UV flashlight that there is, in fact, no ruby going on in this piece 😅). But even if this would've been the case, it would be hardly legit to label these pieces as 'ruby zoisite' (aka anyolite, as we'll see below), when, to the eye, it's 'just' a green mineral peppered with inclusions of another shiny black mineral (pargasite, also see below). So I thought (and I was initially right), well, this is just zoisite, and I got it because I didn't have any zoisite pieces in my collection as yet, and it was a very pretty specimen, disregardless of whether it had ruby in it or not. So that was that, it was added to the haul alongside the others!

Fig. 27 - A bright green chrome-zoisite with inclusions of black pargasite.

But before delving into the rather amusing identification journey for this piece 😅, I would like to point out that I don't know who was more at fault here with the mislabelling of these zoisites, whether it was the actual stall vendor (who was very sweet and helpful throughout, but also didn't strike me as someone who knew a whole lot about the minerals and pieces she was selling), or whether it was rather the vendor's supplier who sold these zoisites to her already labelled as 'ruby zoisite' (or maybe her boss, if the small business wasn't her own). Might have been one of the latter, but no idea. However it may have happened, it is more than obvious that 'ruby zoisite' catches the browsers' eyes much more effectively than just 'zoisite with pargasite', and it's quite possible that the label itself did not stem from ignorance, but was rather clearly meant to be an intentional clickbait 😬. Who doesn't want to buy a piece that includes rubies, one of the most famous gemstones, and for just 3-4€, no less? What a bargain!

   And so, it would be remiss of me not to mention that, even though I didn't care in the slightest about getting a zoisite with no ruby in it and bought it knowing with 99.9% surety that in the piece there were no rubies to be found, many people drawn to a mineral stall such as this one are often not mineralogy experts or long-time collectors who are able to keep honing their identification skills with practice (and we will talk about that honing later on xD). Which means that they may not be able to correctly identify the pieces they're buying and might readily accept the word of the vendors about their nature and origin, trusting in their supposed expertise on the matter (a level of actual expertise which is also relatively absent, in more cases than we would prefer 😬). Whether it might have been more out of amorality or out of ignorance in this particulat case, lack of transparency and unethical and fraudulent practices most certainly exist aplenty in the 'crystal industry', and an example of these practices is to mislabel a lower-value mineral as something that is higher-grade, more expensive or more showy, so as to catch the potential costumers' attention and interest more quickly. 

   This is done way more often than we'd like, not only by selling lower-grade minerals and gems as higher grade, but also coming in the form of dyed, irradiated and/or completely synthetic minerals (which can also be quite lovely, if only there was more transparency on the matter) being labelled as completely natural, often with the intention of selling them for a higher price because of their rarity in nature. Sigh. As another example of this in this stall, there were some blatantly fake 'emerald' and 'ruby' cabochons hailing from India, imitations which are already infamously known to the mineral community to a greater or lesser extent, but rather less to the passers-by 😬 (you can see some of these imitation 'emeralds' in Fig 5, in the right). It's also fair to say, however, that this stall wasn't really scamming costumers price-wise because all of the rough pieces and boxed specimens available (including the zoisites) were quite affordable (most of them were 3-4€ each, more than reasonable for their size and quality). But that doesn't cancel out the fact that the mislabelling of these pieces was misleading (a personal pet peeve), and effectively acting as a clickbait, all the same.

Fig. 28 - Fuchsite (left) and chrome-zoisite (right)

 So that's that on that respect. But not the end of the story on this zoisite, as I then embarked in an unexpected journey of identification doubts for this piece 😅, from thinking it was zoisite with hornblende (it is zoisite and pargasite xD), to zoisite with maybe included biotite instead of pargasite, to 'could it actually be fuchsite instead of zoisite 🤔??' (spoiler, it is not xD), to 'no, it is zoisite, and maybe biotite' again, to, finally, some identification tests and Reddit threads discussing zoisite later, I arrived at 'this is definitely zoisite with pargasite' 😅👍. Quite an annular structure in this journey, overall (all the LOTR and Hobbit puns have been unintended but welcome 🤣).

Me identifying this zoisite like xDD

So yeah. I left the stall fully convinced that I had a zoisite in my possession, and a quick research session into this mineral made me conclude that the black inclusions were probably hornblende (specifically, black pargasite), as zoisite is often accompanied by it. So far, so good! but I suppose that the 'ruby zoisite' mislabelling issue, accompanied by the fact that this is my first zoisite (and so I had nothing to compare it to), suddenly made me start to doubt whether this was actually zoisite or if the stall had mislabelled that too xD. To top it off, I then mixed up in my mind two different hardness tests that I had done on the same day with different pieces, which resulted in me wrongly thinking that this piece could be scratched with my nails 😅, and so it had to have a hardness of 2-3 on the Mohs scale (see Fig. 29). Meanwhile, zoisite has a hardness of 6-7, which is quite a leap on the scale xD. This supposed hardness test, alongside the fact that I was then already wondering whether the black pargasite inclusions could be black mica (biotite) instead, made me immediately leap to the wrong conclusion that the main material was of the mica group as well, specifically a green mica, a fuchsite. 

Fig. 29 - Mohs hardness scale (Source)

  I did redo the hardness test, thankfully, and found out that neither the green mineral nor the black inclusions got scratched with my nails by a long shot, that this piece scratched pieces such as apatite (5 on the Mohs scale) and other minerals up to hardness 6, that it also scratched glass (so it had to be higher on the scale than 5.5), and that quartz (7 on the Mohs scale) just barely managed to make the slightest mark. So this piece had a hardness of approximately 6.5 (between 6 and 7), which fits zoisite's listed hardness to a T, and my first call seemed to be about right. With the wrong hardness test results dispelled, however, the rest of the pieces began to click together as well: The difference in look, feel and luster between this zoisite and my fuchsite became apparent (see Fig. 28, where my small rough fuchsite specimen, mixed with silvery moscovite, showcases a more pearly luster and a characteristic cleavage than the zoisite lacks). 

Fig 30 - Hornblende (top) vs biotite mica (bottom)

  Finally, regarding the conundrum of pargasite vs biotite (see Fig. 30), the platy prismatic/tabular crystals of pargasite can be certainly confused to an extent with the characteristic platy sheets of mica, but the specimen also clearly showcases the difference in hardness between mica and hornblende (a mica, with a hardness of 2.5 on the Mohs scale, will flake easily when handled, leaving glittery specks on your fingers and strewn on your surfaces, while the pargasite crystals on the zoisite specimen, with a hardness of 5-6, don't even budge xD). And also the difference in luster, with both being vitreous, but pargasite also having a luster that is submetalic rather than pearly (mica). 

   So I guess that all of this means that 1) Mineral identification is a lot of fun, albeit hard and confusing at times 😅, and that 2) practice makes perfect (well, it makes better xD) when it comes to honing these skills, for sure.

 Seeing as zoisite doesn't feature on the RBA kiosc collection I'm organizing most of my mineral posts around (apart from hauls), I will now be talking with a bit more detail about zoisite (and also about pargasite, although hornblende in general will feature on the RBA series as well): And before that, now's the time, finally, for some more pictures and a video showcasing the bright green of this chrome-zoisite and the lovely vitreous luster of the combo of zoisite and pargasite in the Sun ✨:

Fig. 31 -  This chrome-zoisite has a bright green hue and presents inclusions of black pargasite.

Fig. 32 - Chrome-zoisite and pargasite in direct late evening sunlight.

Fig. 33 - Chrome-zoisite and pargasite. The lighting in these two photos makes the piece looks rather more reddish than it actually is, which can also lead to error. In real life it only presents a small area that seems to be slightly stained on the surface (although UV light might be needed to know if there are any ruby minute inclusions going on xD).

✨Video (also on TikTok here; bonus slideshow post): 

💎A bit about zoisite (and pargasite): Source 1,  Source 2, Source 3, Source 4, Source 5, Source 6, Source 7, Source 8, Source 9

- Zoisite (also known as saualpite) is a calcium aluminum hydroxy sorosilicate with the (lengthy xD) chemical formula Ca₂Al₃(SiO₄)(Si₂O₇)O(OH). Being the orthorhombic polymorph of clinozoisite (the two minerals are dimorphs, with the same chemical formula but different crystal structure, see Fig. 34), zoisite was formerly assigned to the epidote mineral group but is no longer considered to be a member of it. In spite of this distinction, both zoisite and clinozoisite have very similar physical properties and are often very difficult to distinguish.

 

Fig. 34 - Zoisite&clinozoisite infographic (Source)

  Zoisite (alongside clinozoisite) typically forms in metamorphic rocks in high-presssure and low-temperature conditions, and often through the metamorphic alteration of pre-existing igneous and sedimentary rocks, undergoing chemical changes and recrystallization. In these environments, it can occur in massive form (granular masses), and as prismatic crystals in pegmatites and in veins in schists and marbles. 

  This mineral is relatively hard, 6.5 to 7 on the Mohs scale, and exhibits a perfect conchoidal fracture. Zoisite may be colourless or instead occur in a wide range of colours, from green (chrome-zoisite) and blue to pink, yellow, grey and violet. Transparent blue (and violet) zoisite crystals, coloured by vanadium, are known as tanzanite, a rare variant that was discovered in the 1960s in Tanzania (most of it is nowadays produced and sold by heat treating brown zoisites, changing the oxidation state of vanadium to turn the colour to blue). Thulite (or rosalite) an opaque pink manganese-bearing variety, is also rare. 

  Finally, we have anyolite, or 'ruby zoisite', a rock composed of bright green chrome-zoisite and red corundum crystals (ruby), often also accented by inclusions of black pargasite (or tschermakite, see below). My larger zoisite specimen is pretty much an anyolite without the ruby, so technically not an anyolite at all 😅. Still very lovely, but as we've seen, also mislabelled in a problematic way by the vendors, and the difference between specimens such as mine and actual anyolite (see Fig. 34.1-5) are quite blatant when it comes to the red areas featuring ruby crystals:

Fig. 34.1 - Anyolite (ruby zoisite) with black pargasite (Tanzania). Very similar to my specimen except for the ruby xD (Source)

Fig. 34.2 - A ruby zoisite with black pargasite at Expominerales Madrid 2024.

As part of an April 2024 haul, I finally got my first piece of actual ruby zoisite (see Figs. 34.3-5), a small tumbled one which is quite lovely, with the green of the chrome-zoisite contrasting with the red ruby zones and the black of the hornblende. And the ruby areas in this tumbled anyolite fluoresce very bright red under my UV torchlight, which was also very cool to see. Also see below for a couple of videos of this anyolite in natural and UV light (on Tiktok here and here):

Fig. 34.3 - Tumbled ruby zoisite

Fig. 34.4 - Tumbled ruby zoisite

Fig. 34.5 - Tumbled ruby zoisite

- Pargasite (and also tschermakite), is a complex inosilicate mineral of the amphibole group, and a member of the extended hornblende group of minerals (specifically, part of the hornblende-ferroschermakite group), with the (even more lengthy xD) chemical formula NaCa₂[(Mg, Fe²⁺)₄Al](Si₆Al₂)O₂₂(OH)₂. Amphiboles as a group are inosilicates which typically contain calcium (Ca), aluminum (Al), iron (Fe) and/or magnesium (Mg) in their structures and form prismatic or needlelike crystals. Ferro- and mangano-pargasites (see the formula above) are isomorphs (same crystal structure, different chemical composition), in this case differing in their iron or magnesium content.  'Hornblende' as a term is commonly used informally to refer to any opaque amphiboles, typically dark green to black, which includes tschermakite and pargasite. All individual hornblende minerals have a very similar appearance, and can be practically indistinguishable without individual analysis.

Fig. 36 - Pargasite infographic (Source)

Pargasite is one of the most common amphiboles, typically forming in high-temperature metamorphic rocks, as well as in volcanic and ultramafic  igneous rocks. It occurs as granular masses and as opaque to transparent prismatic or tabular crystals, with a vitreous to submetallic luster (such as the ones featured in my zoisite), and includes not only opaque dark green and black varieties, but also transparent light-coloured ones, as in the case of the highly sought-out bright green transparent pargasite crystals. Some of these varieties are recognized as individual minerals, with pargasite actually being the principal member of its own complex mineral group with a total of 26 species.

✨Some interesting history and STEM trivia about zoisite and pargasite:  

• Zoisite was first described by Abraham Gottlob Werner in 1805, who named the mineral after Carniolan (a region that comprised parts of present-day Slovenia) naturalist Sigmund Zois (1747-1819), who financed  mineral-collecting expeditions. It had been Zois who had sent Werner specimens of the then unknown zoisite (found by mineral dealer Simon Prešern in 1804), from the locality of Saualpe in Carinthia (Austria). Thus its alternative name, saualpite.

• Pargasite is named after the Pargas Valley, a locality in Finland, where dark green to black specimens of this mineral were first found and described. This name was coined in 1814 by Count Fabian Gotthard von Steinheil.

• Uses of zoisite: Both zoisite and clinozoisite are typically found in small quantities, and thus historically these minerals have not been very well-known or widely used either for industrial purposes or in the gemstone market. In spite of this, transparent and/or colourful specimens, such as tanzanite, thulite and anyolite, have gained popularity and are currently highly valued as gemstones, and used for carvings. jewellery and other ornamental purposes. Its rarer varieties are highly sought-after by gemstone and mineral collectors. Albeit less commonly, zoisite has also several industrial applications: As an abrasive for cutting and polishing other materials, due to its hardness, or used in ceramics or as a filler for other composite materials.
  

• Pargasite acts as the main water-storage site in the Earth's upper mantle. Although it becomes unstable at depths greater than 90 km, the presence of pargasite in lherzolite-type ultramafic igneous rocks is also of great scientific value in order to study the temperature ranges at which rocks form in the uppermost levels of the mantle.

Finally,

💎 An infographic video on zoisite and pargasite, including and additional clip and featuring mineralogy facts and historical trivia (also on Tiktok here):

 

5) Aragonite:   

And now we come to the five small boxed minerals from this haul! First is a small pinecone aragonite cluster (see Figs. 37-39 below, as well as Figs. 2, 7, and 11-12 above), originating from Cuenca (Castilla la Mancha, Spain). In my collection, I already had larger pinecone aragonites, but this one is still probably in my top three favourites, with beautiful reddish-brown pseudo-hexagonal prismatic crystals grouped around a central axis (hence the alternative name 'aragonite star clusters').

✨Aragonite will also feature in the upcoming post 4 of my RBA mineral collection series! Also see below for a video showing the lovely crystals and the vitreous luster of this piece in direct sunlight ✨:

Fig. 37 - Pinecone aragonite, in its box.

Fig. 38 - Pinecone aragonite with lovely red-brown pseudo-hexagonal prismatic crystals. Also, look at that luster!

Fig. 39 -  Pinecone aragonite, more angles.

 

✨Video (also on TikTok here; bonus slideshow post): 

 

6) Rhodonite: 

  The second of the small boxed minerals is my first rough rhodonite, which joins my tumbled piece from the RBA collection (see Fig. 44).  Both of my rhodonite specimens are from South Africa, and this one (see Figs. 40-44 below, as well as Figs. 2, 7, and 11-12 above) is a raw piece, displaying the pink hue characteristic of rhodonite, as well as its typical vitreous luster, becoming more pearly on cleavage surfaces. This specimen is homogeneously pink and lacks the brown and black patches of my tumbled rhodonite (corresponding to manganese oxides), but instead includes a curious green patina at the top, which I tentatively guess as being a copper-based mineral(?), possibly malachite (or maybe conichalcite?). It is a curious combination that I personally hadn't seen before (green coatings in rhodonite specimens can be seen here: 1, 2, 3), but that's my best guess at the moment. The green coating doesn't look like epidote or tephroite, the only green minerals I had seen associated with rhodonite so far.

 

✨Read more about rhodonite in the second post in my RBA mineral collection series on this blog. Also see below the pictures for a video with this rough rhodonite in direct sunlight ✨:

Fig. 40 - Rough rhodonite, in its box.

Fig. 41 - This small rough rhodonite displays its characteristic pink colour, as well as a green patina on the top, possibly malachite or a copper-based mineral?

Fig. 42 - Rough rhodonite showcasing an homogeneous pink colour and a green patina of possibly malachite.

Fig. 43 - Rough rhodonite, view from the back.

Fig. 44 - Tumbled (left) and rough (right) rhodonites. The tumbled one shows black and brown patches as a result of manganese oxides.

 

✨Video (also on TikTok here; bonus slideshow post): 

6) Rock crystal: 

For our third mineral in this second half of the haul, we have a beautiful rock crystal (clear quartz) cluster (see Figs. 45-49 below, as well as Figs. 2, 7, and 11-12 above), originating from Brazil. In spite of its small size, this quartz cluster displays some gorgeous well-terminated pyramidal prismatic crystals, with some incredible transparency as well ✨.

✨Rock crystal will also feature in a future installment of my RBA mineral collection series! In the meantime, you can also read about quartz in general in post 1 of this series, and about milky quartz and quartz geodes in post 2. Also see below for a video where we can see the gorgeous crystals and the transparency and vitreous luster of this quartz specimen, in direct sunlight ✨:

Fig. 45 - Rock crystal cluster, in its box.

Fig. 46 - This rock crystal cluster has some gorgeous well-terminated crystals.

Fig. 47 - This rock crystal cluster has some gorgeous well-terminated crystals. I especially love the one at the top!

Fig. 48 - Rock crystal cluster, more angles.

Fig. 49 - Rock crystal cluster, more angles, featuring some really lovely shine on the tallest crystal.

✨Video (also on TikTok here; bonus slideshow post): 

7) Hematoid quartz: 

The fourth boxed mineral is another quartz, this time a red quartz aka hematoid/ferruginous quartz, originating from Morocco (see Figs. 50-53 below, as well as Figs. 2, 7, and 11-12 above). Coloured red by iron inclusions, this hematoid quartz cluster also displays some beautiful well-terminated pyramidal prismatic crystals, as well as a deep red hue and a lovely vitreous luster ✨.

✨Hematoid/red quartz will also feature in other hauls, as well as in a future installment of my RBA mineral collection series! In the meantime, you can also read about quartz in general in post 1 of this series, and about milky quartz, quartz geodes and iron-stained quartz in post 2. Also see below for a video where we can see the gorgeous crystals, vitreous luster and red colour of this quartz specimen, in direct sunlight ✨:

Fig. 50 - Red (hematoid) quartz, in its box.

Fig. 51 - Red quartz cluster, also showcasing some gorgeous pyramidal prismatic crystals.

Fig. 52 - Red quartz cluster, displaying a deep red colour due to iron inclusions, and a lovely luster.

Fig. 53 - Red quartz cluster,more angles.

✨Video (also on TikTok here; bonus slideshow post): 

8) Green tourmaline & quartz: 

And finally, we have a small specimen of green tourmaline (verdelite) crystals in a milky quartz matrix, a piece originating from Brazil (see Figs. 54-57 below, as well as Figs. 2, 7, and 11-12 above). I already have another verdelite as part of the RBA collection, but what I got was a very dark and rather lackluster raw piece that was visually way more similar to an (opaque) black tourmaline than anything else 😅. So I'm definitely happy to now have an specimen with actually greener crystals xD. Even though it's a small piece, there are several prismatic and columnar tourmaline crystals in this specimen (albeit incomplete and half-buried in the quartz matrix), and the combo between the crystals and the quartz matrix is quite lovely. The crystals also show characteristic striations along their long axis, especially when moving the piece to and fro in the light ✨. The main colour of these verdelite crystals is green, but one of them also seems to have a pink zone on the inside when looking at its cross-section (see, for example, Fig. 56). Could this be the closest I've come at the moment to having a watermelon tourmaline, the coveted pink and green bicolour variety? It seems so xD.

✨Tourmaline (both black tourmaline and verdelite) will also feature in future installments of my RBA mineral collection series! You can also read about quartz in general in post 1 of this series, and about milky quartz and quartz geodes in post 2. Also see below for a video where we can see the lovely vitreous shine of the green tourmaline crystals in its quartz matrix, in direct sunlight ✨:

Fig. 54 - Green tourmaline in quartz matrix, in its box.

Fig. 55 - Green tourmaline (verdelite) in quartz matrix, with some nice bright green crystals.

Fig. 56 - Green tourmaline in quartz matrix. One of the tourmaline crystals has a pink zone when looking at its crossection. The nearest I've come to a watermelon tourmaline so far xD!

Fig. 57 - Green tourmaline in quartz matrix, more angles.

✨Video (also on TikTok here; bonus slideshow post): 

And that's it for this haul! Stay tuned for more mineral content with a next installment of the RBA collection series 😁!