The tourmaline Mineral Group





Elbaite, Schorl, and Dravite. Other lesser known members include Uvite, Liddicoatite and Buergerite. There are yet more members of the Tourmaline group, but these are extremely rare and not discussed in this guide.



Tourmaline is extremely popular among collectors and is a well-known gemstone. It is the most multicolored mineral type known, occurring in virtually every color of the spectrum. Individual stones are often multicolored and are unsurpassed in their beauty.



The color of some Tourmaline can be enhanced through



Tourmaline has many interesting optical properties. Many green and blue specimens are strongly



Tourmaline is both



For additional information, see the gemstone section on Tourmaline.

Tourmaline is not a single mineral, but a group of several closely related minerals. The three most well-known members are, and. Other lesser known members includeand. There are yet more members of the Tourmaline group, but these are extremely rare and not discussed in this guide.Tourmaline is extremely popular among collectors and is a well-known gemstone. It is the most multicolored mineral type known, occurring in virtually every color of the spectrum. Individual stones are often multicolored and are unsurpassed in their beauty.The color of some Tourmaline can be enhanced through heat treatment . Some greenish stones can be made deep green, some brownish-red stones can be made red, and some light pink stones can be made colorless through heating.Tourmaline has many interesting optical properties. Many green and blue specimens are strongly pleochroic . When viewed through their vertical axis , such specimens appear darker in color than when seen through their horizontal axis. In other Tourmalines, the color may actually be different when viewed at different angles because of the pleochroism . Certain Tourmalines exhibit a cat's eye effect when polished into cabochon s.Tourmaline is both pyroelectric and piezoelectric . If a specimen is put under a pressure or temperature change, it will generate an electrical charge. When this happens, dust particles become attached to the crystal ends.