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. 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) 😁!