corundum

If the quartz can’t scratch the specimen, it might be beryl or corundum, which are harder than quartz.

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

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.

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

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