The birthstone for the month of October, tourmaline is a stunning gemstone that is found in more hues than any other gem. The name tourmaline comes from “turmali,” the Sinhalese (Sri Lanka) word for “more colors.” Ancient legend says that tourmaline is found in all colors because it travelled along a rainbow, and along the way, gathered all the color’s of the rainbow. Over the centuries, people of royalty have adorned themselves with this unique gemstone. Often times tourmaline will be bi or even tri-colored. A tourmaline that is considered “watermelon,” is green on the outer edges, and pink in the center.
Tourmaline is found in several geological settings, most often in granite pegmatites and their host rocks. This pegmatic tourmaline is generally black in color. It is also found in eluvial and aluvial deposits, due to its relatively high hardness and specific gravity. Tourmaline has also been found in hydrothermal veins of quartz.
Tourmaline is a very complex aluminum borosilicate, there are eleven distinct mineral species of tourmaline based on chemical composition: buergerite, chromdravite, dravite, elbaite, feruvite, foitite, liddicoatite, olenite, povondraite, schorl and uvite. The color seen in tourmaline is from the presence of metal ions (Fe, Mn, Cr, V, Ti and Cu) in its crystal structure. Indicolite is a common name given to blue tourmaline, and Rubellite for deep pink-red tourmaline. The most expensive tourmalines are rich blue in color and rubellite.
Tourmaline are mined in: Africa, Afghanistan, Australia, Brazil, Kenya, Madagascar, Mozambique, Nigeria, Pakistan, Siberia, Sri Lanka, Tanzania, the United States, and Zimbabwe.
Properties, Treatments & Lab Created
Tourmaline is rated a 7 – 7.5 on the Mohs scale.
Heat treatment is sometimes used on tourmaline to lighten dark pieces or to make white and pale pink tourmaline become a richer pink in color. When lightened a dark gray or steel tourmaline will generally become minty green or neon blue.
There is currently no lab created tourmaline, but people often use simulants to imitate tourmaline such as lab created spinel and quartz.