Ruby
Colour and clarity drive a ruby's value, and treatment history matters as much as either. We disclose both.
In short
Rubies are washed from gravels or cut from marble, graded by colour and clarity, and sold with any treatment disclosed.
- Formula
- Al₂O₃ (Cr)
- Density
- 4.0 g/cm³
- Hardness
- 9 Mohs
- Priced in
- Per carat or per lot
What it is
Ruby is the red form of the mineral corundum (aluminium oxide), coloured by chromium. Only diamond is harder. The most valued rubies are a strong, slightly purplish red. Many rubies are heat-treated to improve colour, which must be disclosed.
Supplied as
- Rough
- Calibrated lots
- Specimens
Who buys it
- Fine jewellery
- Collector specimens
- Industrial corundum (lower grades)
What we check before we sell
- 01Gemmological lab report where requested
- 02Heat and treatment disclosure
- 03Origin documentation
From raw to refined
How ruby becomesa set ruby.
Follow ruby through 7 stages, from the moment it leaves the ground to the finished piece. Keep scrolling: each step has its own photograph or film.
Mine · Ruby mining district
Gem country
Rubies are mined from marble and from the river gravels below it. Many workings are small, dug by hand or with simple machinery.
Next commodity
Red garnet