Realgar
ID: 67
Realgar
Chemical Formula
AsS
Hardness (Mohs)
1.5 - 2
Crystal System
Monoclinic
Streak
Orange-red
Luster
Resinous to adamantine
Diaphaneity
Transparent to translucent
Color
Red to orange-red
Crystal Habit / Mode of Occurrence
Prismatic crystals, often short and stubby, can also be granular, massive, or as coatings. Sometimes found as well-formed crystals.
Fun Facts
Realgar is another arsenic sulfide mineral, like orpiment, and is also toxic. Its vibrant red color makes it quite striking. It has been used as a pigment and even in traditional medicine in some cultures, despite its toxicity. Due to its arsenic content, it will tarnish upon exposure to light, altering its color over time.