• Tourmaline is a crystal made up of boron silicate, or “borosilicate.” During formation, borosilicates are capable of joining with a whopping 35 other minerals in various combinations. Therefore, tourmaline is not a single mineral, but a group of minerals.
• The presence of other minerals results in a rainbow of colors, giving tourmaline a wider range of colors than any other gemstone. There are over 100 different colors of tourmaline including white, clear, and black. Tourmaline can even display two or more colors in a single crystal. A crystal can be one color on one end, and a different color on the opposite end, or it can be one color inside the crystal and a different color outside. It was chosen as one of October’s birthstones.
• Because the crystals are prismatic in structure with long striated columns, some can even change color when held at different angles.
• Tourmaline is formed when mineral-laden water vapor, heated by hydrothermal activity, filters into cavities in surrounding rock where it cools into crystals. Later, other vapors carrying different minerals may enter the same crevice, resulting in layers of diverse colors.
• There are tourmalines that encase water in their centers, and quartz crystals that encase tourmaline.
• The word tourmaline springs from the Sri Lankan phrase “tura mali” meaning “unknown gemstones of mixed colors.”
• Pink and red tourmaline are rarer than rubies. One type that’s pink inside and green outside is called “watermelon tourmaline.”
• Tourmaline crystals vary in size from microscopic to over a foot in length. The largest prisms top out at over 220 lbs. (100 kg). The biggest cut and polished tourmaline comes in at just under 200 carats.
• Brazil was the world’s leading source of tourmaline for nearly 500 years, though they were thought to be sapphires and emeralds at first. It was not recognized as a distinct mineral until 1793. Today it’s mined all over the planet, but the only two places in the U.S. where they are found in California and Maine.
• Tourmaline was found in the U.S. for the first time in Paris, Maine in 1821. Since then, many mines have opened throughout the state, and tourmaline is Maine’s state mineral.
• Bigger deposits of tourmaline were found in California in the late 1800s. Since then, tourmaline has surpassed every gemstone in the state in terms of cumulative dollar value.
• The molecular structure of tourmaline results in a feature where the crystals become electrically charged when heated (“pyroelectric”) or from friction when rubbed (“piezoelectric”). Both of these methods result in a negative charge at one end and a positive charge at the other. This make tourmaline handy for use in devices such as sonar instrumentation, pressure gauges, depth gauges, and other scientific equipment.
• Tzu Hsi, the Dowager Empress of China, was the last ruler of the Ch’ing Dynasty, reining from 1860 until she died in 1908. She had a particular fondness for pink tourmaline and secured most of her supply from mines in California. It was distributed among royalty of the court, often being carved into snuff bottles, buttons, carvings, and jewelry. So prodigious were her purchases that the money she spent provided the financial foundation for the bank that eventually became Chase National, which became Chase Manhattan. When she died, she was buried with her head upon a pink tourmaline pillow. Just four years later, the Chinese government collapsed, taking the market for tourmaline down with it.