Realgar
| Colour | Red, Orange, Yellow, Gray |
|---|---|
| Mohs hardness | 1.5–2 |
| Lustre | Resinous to greasy |
| Streak | Red-orange to red |
| Crystal system | Monoclinic |
| Transparency | Transparent |
| Cleavage | Good on {010}; less so on {101}, {100}, {120}, and {110} |
| Chemical formula | or AsS |
| Specific gravity | 3.56 |
What is Realgar?
Realgar, also known as arsenic blende, ruby sulphur or ruby of arsenic, is an arsenic sulfide mineral with the chemical formula α-As4S4. It is a soft mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in association with the related mineral, orpiment. It is orange-red in color, and burns with a bluish flame releasing fumes of arsenic and sulfur. It is trimorphous with pararealgar and bonazziite.
How to identify Realgar
- Lustre: Resinous to greasy.
- Hardness: Mohs 1.5–2 — soft; a knife will scratch it.
- Streak: Red-orange to red.
- Habit: Monoclinic crystal system.
Realgar in different forms
Stones often confused with Realgar
Frequently asked questions
How hard is Realgar?
Realgar is Mohs 1.5–2 on the hardness scale.
What colour is Realgar?
Realgar is typically red, orange, yellow, gray (Red to yellow-orange; in polished section, pale gray, with abundant yellow to red internal reflections).