Topaz is a hard, transparent gemstone that comes in many colors, though it's most famous for its golden yellow and blue varieties. When cut and polished, topaz sparkles brilliantly, making it popular for rings, necklaces, and other jewelry.

Topaz forms deep underground when hot, mineral-rich fluids flow through cracks in rocks and slowly cool over millions of years. The different colors come from tiny amounts of other elements mixed into the crystal as it grows. Imperial topaz, a rich orange-gold variety, is especially prized. Blue topaz can be pale as a winter sky or deep as the ocean.

On the Mohs scale of hardness, topaz ranks 8 out of 10, harder than quartz but softer than sapphire or diamond. This hardness made topaz valuable for more than just beauty: jewelers once used it to test whether other gems were real, since topaz could scratch softer stones.

Topaz is the birthstone for November. Major deposits are found in Brazil, Pakistan, and Russia.