Birthstone
Spinel
Usually described as red through blue.
- Colour
- red through blue
- Month
- August
- Status
- Added laterSpinel was added to August in 2016 by the American Gem Trade Association and Jewelers of America. The two lists compared.
Name and history
The name is the French spinelle, perhaps from the Latin spina, a thorn, for its pointed crystals. For most of its history red spinel went by other names: the transparent red stones were called spinel rubies or balas rubies, after Balascia, the old name for Badakhshan, whose mines were their main historic source, and it was not until 1783 that a mineralogist identified spinel as a mineral distinct from ruby. The Black Prince's Ruby, a fourteenth-century stone set in the Imperial State Crown, is in fact a red spinel.
What it actually is
| Species | Spinel |
|---|---|
| Composition | MgAl₂O₄ |
| Crystal system | cubic |
| Hardness | 8 on the Mohs scale. Hard enough for daily wear; dust will not scratch it. |
| Cleavage | none; indistinct octahedral parting |
| What makes the colour | chromium (Cr³⁺) for red and hot pink, iron for most blues, greys and mauves, and traces of cobalt for the rare vivid blue |
| Mined in | Myanmar, Tanzania, Sri Lanka, Vietnam, Tajikistan |
Hardness, composition and crystal system are standard mineralogical values. Where published sources disagree, the range given covers them.
How it gets damaged
Hard, singly refractive and with no cleavage, so it is among the more forgiving gems to wear and clean; it is nonetheless brittle enough to chip on a sharp blow, and fracture-filled stones should not go in an ultrasonic bath.
This describes the physical stone. Nothing on this site claims a gemstone has any therapeutic or healing effect — see the disclaimer.
Which list it is on
| Month | The 1912 list | Today's list |
|---|---|---|
| August | — | Yes |