Precious gemstone:

 The true sapphire is deep blue, yellow corundum is called yellow sapphire or Oriental topaz.

Pale pink stones are called pink sapphire.

Excellent sapphires occur in alluvial deposits of sand and gravel in Sri Lanka.

Other important sources of the stones are Thailand, India, Afghanistan, China, the Ural Mountains and elsewhere in the former Soviet Union, and Queensland, Australia.

In the United States sapphires are found in North Carolina, and near Helena, Montana.

Sapphires and rubies are used as hard bearings in watches and scientific apparatus.