Amethyst
purple · Quartz family
| Also known as | Quartz (Quartz family) |
|---|---|
| Colour | Purple |
| Mohs hardness | 7 (lower in impure varieties) |
| Lustre | Vitreous/glassy |
| Streak | White |
| Crystal system | Trigonal |
| Transparency | Transparent to translucent |
| Cleavage | None |
| Fracture | Conchoidal |
| Chemical formula | Silica (silicon dioxide, SiO) |
| Specific gravity | 2.65 constant; variable in impure varieties |
What is Amethyst?
Amethyst is a violet variety of quartz. Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication. Amethyst, a semiprecious stone, is often used in jewelry. It occurs mostly in association with calcite, quartz, smoky quartz, hematite, pyrite, fluorite, goethite, agate, and chalcedony.
How to identify Amethyst
- Lustre: Vitreous/glassy.
- Hardness: Mohs 7 (lower in impure varieties) — hard enough to scratch glass.
- Streak: White.
- Habit: Trigonal crystal system.
Amethyst in different forms
Stones often confused with Amethyst
Frequently asked questions
How hard is Amethyst?
Amethyst is Mohs 7 (lower in impure varieties) on the hardness scale.
What colour is Amethyst?
Amethyst is typically purple (Purple, violet, dark purple).