Oropimente
Oropimente is a mineral with formula As₂S₃, in the Sulfuros group. This specimen comes from Getchell Mine, Adam Peak, Humboldt County, Nevada, Estados Unidos and joined the Terrium collection in 2026.
Description
Exfoliated, scaly to platy orpiment, with the typical orange indicating admixture of realgar; almost solar highlights on the purer golden-yellow zones.
History of this specimen
My first trade at Deifontes, with Víctor, for a sampleite from Australia.
About Oropimente
Orpiment is, first and foremost, a toxic mineral: it contains arsenic and must be handled with care. It is also one of the most visually striking species, recognised for its golden-yellow, almost solar colour with orange variations, and for its silky, platy, layered structure. Seen close up, it commonly shows exfoliated crystals, delicate plates, or fibrous masses with a lustre between resinous, greasy and silky. One of its most surprising characteristics is its density: it weighs far more than it appears. The eye reads a scaly, bright, light material, yet in the hand the brain registers a discrepancy: it is heavy, almost twice the same volume of quartz. Another detail: the auripigmentum or "golden pigment" fascinated painters for centuries, but it had a serious problem beyond its toxicity. It was chemically incompatible with some colours. When mixed with lead-derived pigments, such as white lead, the paint ended up blackening. Many old paintings lost their golden or luminous details because of this chemical conflict between pigments.
About the locality
Getchell is a Carlin-type gold deposit where the metal is invisible to the naked eye because it is intermixed with minerals such as pyrite and arsenopyrite. Its extraction requires complex chemical processes with cyanide (the same compound with which Alan Turing committed suicide). In a sea of grey rock, miners knew that where the yellows, reds and fiery oranges of arsenicals appeared, gold was close.
Technical data
- Catalogue No.
- 0409
- Composition
- As₂S₃
- Name
- Oropimente
- Group
- Sulfuros
- Category
- Meritum Persé
- Mine
- Getchell Mine
- District / Municipality
- Adam Peak
- Province
- Humboldt County
- Region
- Nevada
- Country
- Estados Unidos
- Size (cm)
- 6 x 2.5 x 2.5
- Weight
- 46.1 g
- Acquired
- 2026
- Etymology
- From Latin "auripigmentum", "golden pigment", for its characteristic colour.
- Quality
- Buena
- Value trend
- Estable
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