Tourmaline - Properties and Source Countries

Joel A. Bartsch serves as CEO of the Houston Museum of Natural Science. In this role, Joel Bartsch oversees the museum’s permanent collections, including the Cullen Hall of Gems and Minerals. The exhibition features exquisite examples of polish and raw stones, including several varieties of tourmaline.

Tourmaline is a semi-precious silicone-based stone that contains traces of various metals and minerals. They are found across the world and naturally form crystalline towers. Polished tourmaline is a popular gem due to its status as the October birthstone. While these stones come in various colors, the most desirable include bright blue, caused by copper elements, and “watermelon” tourmaline, which features a pink interior and green exterior.

When tourmaline was first discovered by Europeans in the 1500s, it was classified as an emerald. Several centuries later, gemologists identified the stone as its own category and named it after the Sri Lankan word for similarly colored gems. Some of the largest deposits of tourmaline in the world are in North and South America. Mines in Afghanistan produce crimson-colored tourmaline, while Paraiba, Brazil, is best known for its cerulean blue gems.