Tourmaline" is the name of a large group of boron silicate minerals. These minerals share a common crystal structure and similar physical properties - but vary tremendously in chemical composition. The wide range of compositions and color zoning within crystals causes tourmaline to occur in more colors and color combinations than any other mineral group.

Tourmaline is one of the world's most popular gemstones and it serves as a birthstone for the month of October. Because of its popularity, tourmaline is easy to find in jewelry stores. Well-formed tourmaline crystals are also valued by mineral specimen collectors. Specimens with attractive colors and crystal forms can sell for thousands of dollars.