Diamonds have fascinated people all over the world with their special allure and brilliance, with diamonds fetching amazing prices when cut and polished. Diamonds are valuable because of their rarity with only a handful of mines in the world producing diamonds.
Diamonds are crystals of carbon that have typically formed deep in the earth at depths of between 150 to 250 km. The diamonds are brought to the surface by volcanoes that have tapped deep enough into the earth to source the diamonds. Usually the volcanic rocks are composed of kimberlite or lamproite.
The Australian and Indian diamond mines of Argyle , Ellendale and Panna (respectively) are in lamproite rocks, whereas all of the other diamond mines in the world are found in kimberlite rocks. Diamonds that are washed out of these kimberlite and lamproite rocks by weathering and erosion are found in alluvial deposits. Some of the largest diamonds that have ever been found in the world have been mined from the alluvial deposits of India and Africa.
I have compiled information pages on some of my areas of interest and these can be followed in the following links
Argyle Diamond Mine