monoclinic Sulfides
Realgar
Formula As4S4
Crystal Structure
#! Species: Realgar
#! System: Monoclinic (2/m)
#! Habit: Short prismatic with multiple dome forms
monoclinic[2/m]:{110}@1.0 + {010}@0.8 + {120}@0.6 + {011}@0.5 + {101}@0.4
monoclinic
2/m
{110} {010} {120} {011} {101}
Quick Facts
Hardness
1.5
Specific Gravity
3.52
Refractive Index
2.538
Optical Character
Biaxial -
Physical Properties
- Crystal System
- monoclinic
- Hardness (Mohs)
- 1.5
- Specific Gravity
- 3.52
- Cleavage
- Good {010}
- Fracture
- Conchoidal
- Lustre
- Resinous to adamantine
Optical Properties
- Refractive Index
- 2.538
- Birefringence
- 0.166
- Optical Character
- Biaxial -
- Pleochroism
- Strong (red to orange-red shades)
Characteristics
Colours
RedOrange-redVermilionDeep red
Localities
China (Hunan, Yunnan)Romania (Baia Sprie)Nevada (USA - Getchell Mine)North MacedoniaSwitzerland (Lengenbach)Washington (USA)
Crystal Forms
prismpinacoidstriated crystals
Notes
CAUTION - contains arsenic; degrades to pararealgar in light; store in darkness; wash hands after handling
Related Minerals
Other minerals in the monoclinic system
