4.1" Vibrant Orange Orpiment Formation - Peru

Orpiment is a bright orange to yellow arsenic sulfide mineral. Its name is derived from the latin phrase auripigmentum, meaning “gold pigment”. It is frequently found as a decay byproduct and in association with another arsenic mineral, realgar. Orpiment crystals are commonly found in dense groupings containing small, prismatic crystals, often with chisel-shaped or triangular pyramidal terminations.

Orpiment contains a significant amount of the poisonous mineral arsenic. While it’s not going to pose a health hazard sitting on a shelf, it’s recommended that you wash your hands after handling it.

Realgar is an arsenic sulfide mineral with the chemical formula of AsS. Realgar is known for its lustrous red hue, and pristine specimens can be transparent with sharp crystals. The crystal structure is typically stubby and prismatic, though botryoidal and earthy clumps can form as well.

Following prolonged/repeated periods of time under light, realgar will alter to pararealgar. If further left exposed, the pararealgar will crumble to a yellow dust. This mineral instability is particularly troublesome for museums where consistent light exposure has caused specimens to crumble over time. However, short, periodic exposure to light shouldn't alter realgar specimens.

Realgar contains a significant amount of poisonous arsenic, making it somewhat toxic. Therefore, we recommend washing your hands following handling.