mineral
Orpiment
Arsenic Trisulfide (As2S3)
AI-generated identification · may be incorrectMohs hardness of 1.5 to 2, vivid lemon-yellow to golden-orange color, resinous to pearly luster, monoclinic crystal system, and perfect cleavage in one direction.
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Physical properties
Mohs hardness of 1.5 to 2, vivid lemon-yellow to golden-orange color, resinous to pearly luster, monoclinic crystal system, and perfect cleavage in one direction.
Formation & geological history
Formed primarily in low-temperature hydrothermal veins and hot springs, often associated with realgar.
Uses & applications
Historically used as a pigment in paints and as a component in early fireworks, though largely abandoned due to high toxicity.
Geological facts
Orpiment contains high concentrations of arsenic and was famously used by ancient alchemists trying to transmute metals into gold.
Field identification & locations
Easily identified by its bright yellow color and low hardness, typically found in volcanic fumaroles and hydrothermal deposits worldwide.
