Arsenic Family Minerals: Parts I and II

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PinkDiamond
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Arsenic Family Minerals: Parts I and II

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I've always wondered why people want to collect toxic minerals, but people do, and I've seen jewelry with realgar that made me wonder if the cutter suffered any ill effects from cutting them. Do any of you collect minerals containing toxic elements? :?:

Arsenic Family Minerals Part I: Liroconite, Clinoclase, Olivenite and Chalcophyllite
By Admin -
November 1, 201


Image
This arsenopyrite specimen from the Panasquiera mine, in Portugal, features a natural and unusual iridescence. (Photo courtesy irocks.com)

Story by Bob Jones


"Arsenic is a lethal poison, but nature uses it to create some very beautiful minerals. We are all familiar with the more important arsenides, like primary arsenopyrite, and secondary arsenates like adamite and legrandite are very well known and frequently discussed. These are the subjects of a later article.

That leaves a large suite of arsenic species that may be less widely known, but certainly eagerly sought by collectors. Others are so uncommon or rare that they do not lend themselves to the collector market.

Uncommon And In Demand

Quite uncommon species that are still well worth describing because they are in demand among collectors are arsenic species like liroconite, clinoclase, olivenite and chalcophyllite, which are very attractive and have been found in well-crystallized specimens.

The mines of Cornwall, England, which produced arsenopyrite as one of their major ores, are well-known sources of these four secondary species. Arsenic, a semimetal, and the metals copper and tin were abundant enough to be mined and processed there.

The element arsenic has been recognized for centuries. It was among a small group of native elements long known to the ancients who dabbled in alchemy, the pseudo-science of the Dark Ages. Researchers doubt pure, or native, arsenic was well known in those ancient times, as it has always been a very rare natural element.

What the alchemists called arsenic was more likely ... "

https://www.rockngem.com/arsenic-family ... ophyllite/



Arsenic Family Minerals: Part II — Erythrite, Realgar, Orpiment and Scorodite
By Admin -
November 11, 2018


Image
In this specimen from the Schneeberg district of Saxony, 4-cm-long crystals of erythrite rise from a shard of quartz. (Daniel mine) (Photo courtesy The Arkenstone/www.irocks.com)

Story by Bob Jones

"There’s a large number of minerals whose chemistry includes arsenic combined with oxygen: the arsenides. Many of them are very rare or come from some obscure locality that has not produced enough specimens to add significantly to the collector market.

Fortunately, however, there are a significant number that are readily available in quantity to please all collectors. These include adamite, legrandite and mimetite, which have been described in the literature often enough for information on them to be readily available.

Cornwall Suite of Species

Historically, a lovely suite of arsenic species was commonly collected in Cornwall, England. Several of them were new species at the time, and enough specimens were found to supply the collector and scientific markets. Some of these specimens still survive today.

Image
This specimen of orpiment crystals shows some alteration of the orpiment. (Shimen mine, China) (Photo courtesy The Arkenstone/www.irocks.com)

The suite includes clinoclase, liroconite, chalcophyllite and olivenite, which were
described in Part I of this series. A serious collector should keep an eye out for them, as they add a historical dimension to a collection. Even today, specimens of these arsenic species can be seen on display, and they may even show up for sale.

This leaves us with a suite of very colorful arsenides that is available in quantity today. The group includes such beauties as erythrite, realgar, orpiment, and very interesting, but uncommon, scorodite. The first three of these minerals are certainly common enough and are intensely colorful. Scorodite is not as common as the other three, but is found in several noted specimen localities, and this iron arsenate shows a curious color phenomenon.

There is some resistance to collecting realgar and orpiment because of the fear of handling arsenic minerals. ... "

https://www.rockngem.com/arsenic-family ... scorodite/
PinkDiamond
ISG Registered Gemologist


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