This is a small specimen of orpiment that is encrusted in elongated realgar crystals from Peru. The orpiment has a rich yellow-orange coloration, while the realgar crystals are candy-apple red. It measures 1.1" wide and would make an excellent addition to any mineral collection.
Orpiment a bright, orange to yellow arsenic sulfide mineral, whose 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, with the most pristine specimens being transparent with sharp crystals. The crystal structure is typically stubby and prismatic, with botryoidal and earthy clumps known to be possible formations 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 has especially been experienced in museums where consistent light exposure has caused specimens to crumble over time. However, periodic exposure to light shouldn't alter realgar specimens.
Realgar contains a significant amount of poisonous arsenic, making it somewhat toxic. Therefore, washing hands following handling of realgar specimens, is recommended.