Birthstone
Diamond
Usually described as colourless.
- Colour
- colourless
- Month
- April
- Status
- 1912 and todayOn the list adopted in 1912, as a birth-stone, and still on today's. The two lists compared.
Name and history
The word came through Old French diamant and Medieval Latin diamantem from the Latin adamantem, which first meant the hardest metal and later the diamond, and from the Greek adamas, unbreakable or inflexible, the same source as the English adamant. The change from ada- to dia- happened in Vulgar Latin, where the word was reshaped by the many Greek words that begin with dia-. The largest gem-quality rough diamond ever found, the Cullinan, was discovered at the Premier mine in Cullinan, east of Pretoria, in January 1905, and weighed 3,106 carats.
What it actually is
| Species | Diamond (native element, carbon) |
|---|---|
| Composition | C |
| Crystal system | cubic |
| Hardness | 10 on the Mohs scale. Harder than anything it is likely to meet. |
| Cleavage | perfect in four directions (octahedral, {111}) |
| What makes the colour | pure diamond is colourless; nitrogen impurities give yellow to brown, boron gives blue, and plastic deformation of the lattice gives pink, red and much brown, while green comes from natural irradiation |
| Mined in | Russia, Botswana, Canada, Democratic Republic of the Congo, South Africa |
Hardness, composition and crystal system are standard mineralogical values. Where published sources disagree, the range given covers them.
How it gets damaged
The hardest natural material but not the toughest — four perfect cleavage directions mean a sharp blow on the right plane will split it cleanly, and it burns in air above about 700 °C, so it is vulnerable to a jeweller's torch.
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 |
|---|---|---|
| April | Birth-stone | Yes |