Crystaline aluminium oxide (Al3O2) with some impurities added (that's right, they're made out of aluminium and air).. The actual mineral (Al3O2) is called corundum. This is clear if entirely pure, but can take on various colours due to impurities. If the stone is any shade of red (even if also slightly orange, brown, or even purple) then it's called a ruby. If it's any other colour (including pink), it's a called a sapphire.
The name corundum comes from Hindi ("kurand").
Rubies are the 3rd most valuable gemstone, after diamonds and emeralds. The most valuable rubies are rare specimens that reflect either a star-like structure or different shades of red from different angles. Along with sapphires, rubies are the second hardest stone, only after diamonds. This is because of the densely packed crystalline structure.
Artifical rubies are made using a flame fusion process. Synthetic rubies are arguably more ethical to wear, given that the extraction of naturally occuring gemstones may have negative environmental, social and economic consequences.
The name corundum comes from Hindi ("kurand").
Rubies are the 3rd most valuable gemstone, after diamonds and emeralds. The most valuable rubies are rare specimens that reflect either a star-like structure or different shades of red from different angles. Along with sapphires, rubies are the second hardest stone, only after diamonds. This is because of the densely packed crystalline structure.
Artifical rubies are made using a flame fusion process. Synthetic rubies are arguably more ethical to wear, given that the extraction of naturally occuring gemstones may have negative environmental, social and economic consequences.
