Tourmaline

Tourmaline is not a single mineral but a group of closely related boron silicate minerals, and it occurs in a wider range of colours than almost any other gemstone. Most gem tourmaline belongs to the species elbaite, while black tourmaline (schorl) is the most common member of the group and brown tourmaline is usually dravite.

Many colour varieties have their own trade names: rubellite (pink to red), indicolite (blue), verdelite (green) and achroite (colourless). Watermelon tourmaline has a pink core and a green rim, and bi-coloured and multi-coloured crystals are popular with collectors. Paraiba tourmaline, first discovered in Brazil in the late 1980s, owes its intense neon blue-green colour to copper and is among the most valuable of all coloured gemstones.

The name comes from the Sinhalese word "toramalli", a term used in Sri Lanka for coloured gem gravels. Tourmaline was often confused with other gems until the 19th century, and some historical "rubies" have turned out to be red tourmaline. When heated or squeezed, tourmaline crystals develop an electrical charge (pyroelectric and piezoelectric effects), which is why Dutch traders called it the "Ceylonese magnet": it could attract and then repel ash from a pipe.

Tourmaline is strongly pleochroic, showing different shades or depths of colour when viewed from different directions. Some stones are heat-treated or irradiated to improve their colour. Black tourmaline is widely used for beads, and multicoloured tourmaline chips are popular for jewellery making.

Tourmaline at a glance

Caring for tourmaline

Tourmaline is hard (7 – 7.5 on the Mohs scale) and suitable for everyday jewellery, but it can be brittle and should be protected from hard knocks. Clean it with warm soapy water and a soft brush. Avoid ultrasonic and steam cleaners, especially for stones with inclusions or fractures, and avoid sudden temperature changes and high heat, which can damage or alter the stone.

In folklore

The beliefs below are traditional folklore, included for interest. They are not scientifically proven, and nothing here is medical advice.

Ancient legend in Egypt told that tourmaline travelled along a rainbow from the centre of the earth, gathering all of its colours on the way. Dutch traders used it to clean ash from their pipes, thanks to its ability to attract ash when warmed. The Empress Dowager Cixi of China loved pink tourmaline and bought large quantities from California in the early 1900s. Tourmaline is a birthstone for October in the American list and the traditional gift for an 8th wedding anniversary.

Tourmaline is traditionally considered a protective and balancing stone, with each colour given its own meaning. Black tourmaline is believed to shield the wearer from negative energy and to be grounding. Pink tourmaline is associated with love, compassion and emotional healing, and green tourmaline with vitality and nature. Crystal healing lore also holds that tourmaline relieves stress and promotes self-confidence.

Related stones

Varieties include schorl (black), dravite (brown), elbaite, rubellite, indicolite, verdelite, achroite, watermelon tourmaline and Paraiba tourmaline. Stones that can look similar include ruby, spinel, emerald, peridot, garnet, topaz and black onyx.

For the technically minded

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