Orpiment
Species
Uncommon · As₂S₃
Arsenic trisulfide of low-temperature hydrothermal veins, hot springs and fumaroles, and a common alteration product of realgar. Its golden colour made it a prized pigment, though its arsenic made it a hazard to painters.
Identity
- Formula
- As₂S₃
- Chemical class
- Sulfide
- Also known as
- King's yellow, Yellow arsenic
Crystallography
- Crystal system
- Monoclinic
- Habits
- Foliated, Massive, Prismatic
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 1.5
- Density
- 3.49 g/cm³
- Luster
- Resinous, Pearly
- Colors
- yellow, orange-yellow, golden yellow
- Streak
- pale yellow
- Transparency
- Transparent, Translucent
Geology
- Origins
- Volcanic, Hydrothermal
- Host rocks
- Volcanic rock
- Associated minerals
- Realgar, Stibnite, Calcite, Barite
- Geography
- Turkey, China, USA (Nevada), Peru, Iran
Classification
- Rarity
- Uncommon
- Gem quality
- No
Arcane properties
- Affinity
- Shadow, Arcane
- Effects
- Illusion, Warding
- Planar origin
- Material Plane
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, Orpiment. Mineral Data Publishing, Handbook of Mineralogy, 2001.
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