Ruby
red · Corundum family
| Also known as | Corundum (Corundum family) |
|---|---|
| Colour | Red |
| Mohs hardness | 9.0 |
| Lustre | Subadamantine, vitreous, pearly (on partings) |
| Streak | White |
| Crystal system | Trigonal |
| Transparency | Transparent, translucent |
| Cleavage | No true cleavage |
| Fracture | Conchoidal, splintery |
| Chemical formula | Aluminum oxide with chromium, AlO:Cr |
| Specific gravity | 3.97–4.05 |
What is Ruby?
Ruby is a pinkish-red to blood-red-colored gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires, and rubies are also sometimes referred to as "red sapphires".
How to identify Ruby
- Lustre: Subadamantine, vitreous, pearly (on partings).
- Hardness: Mohs 9.0 — hard enough to scratch glass.
- Streak: White.
- Habit: Trigonal crystal system.
Ruby in different forms
Stones often confused with Ruby
Frequently asked questions
How hard is Ruby?
Ruby is Mohs 9.0 on the hardness scale.
What colour is Ruby?
Ruby is typically red (Orangy red through strongly purplish red).