Corundum Tumbled

The corundum family of gemstones consists of ruby and sapphire. Corundum is very compact, dense, and lacks gemstone cleavage. It's also the second hardest natural mineral after diamond. Gem-quality corundum is also quite rare. ... All other colors of corundum, including colorless, are called sapphires.

Corundum is a mineral species that includes two world's most precious gemstones, ruby and sapphire. Since they are the same mineral, sapphire and ruby are often found together. Sapphire is far more common variety, as ruby requires a specific element and an appropriate host rock to supply its essential chromium.

1 inch to 1 1/2 inches +/- in diameter.