Corundum Mineral Summary

Corundum is the third hardest natural mineral known to science, with diamond and moissanite being the only minerals with a greater hardness. It is is commonly known in its red and blue gem forms as ruby and sapphire, although the colour of conundrum is highly variable and can also be found in grey, clear, pink, yellow, brown and purple. Although corundum itself is fairly common, in its gem form it is quite rare hence why they are some of the most expensive gemstones in the world, and the oldest known to man. Its chemical formula is Al2O3 and is a naturally occurring aluminium oxide mineral. It crystallizes in a hexagonal system forming pyramidal or rounded barrel shapes. Due to its hardness and chemical resistance, corundum can be found deposited inside the earth long after other minerals have been destroyed. Over time when the mineral deposits become concentrated they become sources of rubies and sapphires which are found in a number of places in the world such as Burma, India, Afghanistan, Sri Lanka, Cambodia and other areas.

Even in the United States you can find huge deposits of corundum. Montana has huge deposits of ruby as well as parts of California. Corundum's hardness makes it makes it especially useful as an abrasive and is widely used in the manufacturing of sand papers, grinding wheels, cutting tools and polishing compounds. Rubies and sapphires are rarely mined from the rocks in which they form, instead they are more commonly found from stream sediments. Due to corundum's hardness and resistibility rubies and sapphires are able to survive the abrasive actions of streams. What makes rubies red is that the corundum is contaminated by traces of Chromium, whilst it's titanium and irons that contaminates chromium to appear blue to form sapphire. In its gemstone form it's so rare that the biggest piece ever found was about 2 feet long in a foot in diameter, which was found in Transvaal in South Africa. Corundum can be found in numerous locations in Southern Africa. Malawi and Mozambique are rich in Corundum. The Corundum Trader is involved in several mining exploits in Malawi and Mozambique where high quality blue corundum can be found.