Geology Home Page
Roger Weller, geology instructor
Chemical Group: sulfide
Chemical Formula: As2S3
Color: lemon-yellow to brownish yellow Streak: pale yellow
Luster: pearly, resinous Transparency: transparent
Hardness: 1.5 to 2 Specific Gravity:
Cleavage: one direction Tenacity: brittle
Crystal Forms and Habits:
Crystals are usually small.
Orpiment often occurs in foliated, columnar, or fibrous masses.
Mineral Associations: Commonly occurs with realgar, stibnite, calcite, gypsum, barite.
Uses: arsenic ore
Toxicity: when-swallowed- very high when inhaled- very high