corundum

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

A. Both rubies and sapphires are mostly the same clear mineral: aluminum oxide, in a crystalline form called corundum.

From New York Times

After all, sapphires and rubies are built of the same basic mineral, corundum, a crystallized collaboration of aluminum and oxygen that would be transparent and colorless if not for some artful chemical doping.

From New York Times

I was not sure if it was a diamond or corundum, a sparkling stone that has little value.

From BBC

The Bronco mane and eyeball were created from orange sapphires while the head features pave-set diamonds and custom-cut corundum blue stone.

From Washington Times

Unlike blue sapphires, which have complete clarity of colour, blue star sapphires, a form of corundum, are opaque – but when placed under light reveal a six-line star.

From The Guardian