Judging quality
Very soft, flexible cleavage flakes, unmistakable orange-gold. Sulfur is brittle and paler; gold is metallic and heavy.
Sulfide
Orpiment
Arsenic trisulfide in sheaves of golden foliated blades with a resinous to pearly flash. It usually grows alongside realgar, the pair making one of the most striking red-and-gold associations in mineralogy.
Care
Toxic and light-sensitive, like realgar. Dark storage, closed case, wash hands.
History & lore
The name is from the Latin auripigmentum, gold pigment — the yellow of medieval manuscripts before safer alternatives arrived.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Orpiment
- What is Orpiment?
- Arsenic trisulfide in sheaves of golden foliated blades with a resinous to pearly flash. It usually grows alongside realgar, the pair making one of the most striking red-and-gold associations in mineralogy.
- How hard is Orpiment and what is it made of?
- Orpiment is a Sulfide-family mineral with the composition As2S3. It crystallizes in the monoclinic system and rates 1.5-2 on the Mohs hardness scale. It occurs in golden, yellow, amber.
- Where does Orpiment come from?
- Notable localities for Orpiment include Peru (Quiruvilca), Hunan, China, Nevada, USA, Russia.
- How do you tell good Orpiment from filler?
- Very soft, flexible cleavage flakes, unmistakable orange-gold. Sulfur is brittle and paler; gold is metallic and heavy.
- How do you care for Orpiment?
- Toxic and light-sensitive, like realgar. Dark storage, closed case, wash hands.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.