Quantcast

Mohs scale of mineral hardness Reference Libraries

Page 1 of about 1 Articles
Corundum
2005-05-26 11:05:25

Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. Corundum is naturally clear, but can have different colors when impurities are added. Transparent specimens are used as gems, called ruby if red, while all other colors are called sapphire. The word corundum comes from the Hindi kurand. The oxygen atoms in corundum are arranged in a hexagonal...

Word of the Day
aphotic
  • Having no light.
  • Of or relating to the region of a body of water that is not reached by sunlight and in which photosynthesis is unable to occur.
The word 'aphotic' comes from Greek roots meaning 'without' and 'light'.
Related