A gemstone is a mineral or rock that has been cut and polished for use in jewelry or other decorative purposes.

Natural Paraiba tourmaline, padparadscha sapphire, and alexandrite are some of the rarest and most desirable gemstones used in fine jewelry. Larger, precious gemstones like emeralds, sapphires, and rubies are also considered rare and highly sought after.

Diamond is the hardest gemstone, rating 10 on the Mohs hardness scale. Learn more in our Diamond Guide.

A professional gemologist can verify authenticity by examining factors like the stone’s color and clarity.

The cost of a gemstone can vary from a few dollars to millions per carat depending on market demand as well as its type, quality, and rarity.