Smoky Quartz
browngrayblack · Quartz family
| Also known as | Quartz (Quartz family) |
|---|---|
| Colour | Brown, Gray, Black |
| Mohs hardness | 7 – lower in impure varieties (defining mineral) |
| Lustre | Vitreous – waxy to dull when massive |
| Streak | White |
| Crystal system | α-quartz: trigonal trapezohedral class 3 2 β-quartz: hexagonal 622 |
| Transparency | Transparent to nearly opaque |
| Cleavage | {0110} none |
| Fracture | Conchoidal |
| Chemical formula | SiO 2 |
| Specific gravity | 2.65; variable 2.59–2.63 in impure varieties |
What is Smoky Quartz?
Smoky quartz is a brown to black, translucent variety of quartz. It ranges in clarity from almost complete transparency to almost-opaque black crystals. Smoky quartz is popular as a gemstone and as a collectible crystal.
How to identify Smoky Quartz
- Lustre: Vitreous – waxy to dull when massive.
- Hardness: Mohs 7 – lower in impure varieties (defining mineral) — hard enough to scratch glass.
- Streak: White.
- Habit: α-quartz: trigonal trapezohedral class 3 2 β-quartz: hexagonal 622 crystal system.
Smoky Quartz in different forms
Stones often confused with Smoky Quartz
Frequently asked questions
How hard is Smoky Quartz?
Smoky Quartz is Mohs 7 – lower in impure varieties (defining mineral) on the hardness scale.
What colour is Smoky Quartz?
Smoky Quartz is typically brown, gray, black (Brown, gray, black).