About this object

Sapphire is a gem variety of the mineral corundum.  Pure corundum is colorless, but small amounts of impurities in the crystal structure can produce a range of vivid colors.  A few atoms of chromium tint corundum the deep red color of ruby, the most prized corundum gem.  Iron and titanium, on the other hand, are responsible for the deep blue color of sapphire.  Other impurity atoms can color corundum crystals a range of hues, from pink, yellow, and orange to purple, green, and even black.  Corundum gems other than red or blue are called fancy colored sapphires. The fancy colored sapphires pictured here range in size from 10.3 to 92.6 carats.  The green and large yellow sapphires are from Burma; the others are from Sri Lanka.