Tourmaline

About Tourmaline

The most colorful gemstone family - it occurs in every color of the spectrum. Bi-colored and tri-colored specimens exist (watermelon tourmaline has green outside and pink inside). Paraiba tourmaline from Brazil can sell for $10,000+ per carat - its neon blue-green color is caused by copper. It is pyroelectric and piezoelectric - it generates an electric charge when heated or squeezed. Dutch traders used it to clean pipes by attracting ash (they called it aschentrekker, ash puller). Over 30 species exist. It was often confused with other gems throughout history - the last Russian Empress Catherine the Great had a large collection misidentified as rubies.