Orpiment

Orpiment – As2S3
Elements: Arsenic, Sulfur
Class: Sulfides
Crystal System: Monoclinic
Hardness: 1.5-2
Gypsum
Talc (1)Diamond (10)
Very soft. A fingernail scratches it easily.
Origin: Twin Creeks Mine, Nevada – Usa
Did you know?

Orpiment's brilliant gold-yellow made it a prized painter's pigment for centuries, known as King's yellow, long before anyone worried that it is an arsenic mineral.