Proustite
Species
Rare · Ag₃AsS₃
Light ruby silver: scarlet vermilion crystals of silver arsenic sulfide with an adamantine lustre, dulling to black on exposure to light. Proust told it apart from its antimony twin pyrargyrite by analysis in 1804. A late mineral of silver veins, found at many mines but seldom an important ore alone; Chañarcillo in Chile gave magnificent groups, Freiberg and Joachimsthal fine ones.
Identity
- Formula
- Ag₃AsS₃
- Chemical class
- Sulfide
- Also known as
- Light ruby silver, Light red silver ore, Ruby silver
- Ore of
- Silver
Crystallography
- Crystal system
- Trigonal
- Habits
- Prismatic, Rhombohedral, Scalenohedral, Massive
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 2
- Density
- 5.57 g/cm³
- Luster
- Adamantine
- Colors
- red, orange-red
- Streak
- vermilion
- Transparency
- Translucent
Geology
- Origins
- Hydrothermal
- Host rocks
- Granite
- Associated minerals
- Silver, Acanthite, Tetrahedrite, Chlorargyrite
- Found in
- Hydrothermal vein (lode)
- Geography
- Chile (Chañarcillo), Germany (Freiberg, Marienberg, Niederschlema), Czech Republic (Jáchymov, Příbram), France (Sainte-Marie-aux-Mines), Mexico (Batopilas), USA (Poorman mine, Idaho)
Classification
- Rarity
- Rare
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Proustite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Proustite. Wikipedia.
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