The Colours of Tourmaline, Part 1: What is Tourmaline?

By Yaĝé Enigmus

Tourmaline is an exceptionally beautiful gemstone that comes in numerous shades and hues. This gem of many faces has been valued since ancient times, and today tourmaline is among the stones most sought after by gemstone enthusiasts from all over the world. Tourmaline is a wonderful addition to almost any piece of custom jewellery and provides countless options from which to choose.

What many people may not know is that tourmaline is actually the name for a group of cyclosilicate minerals and does not refer to a single stone. The word “tourmaline” is derived from the Sinhalese word “toramalli” which was used to refer to a number of different brightly coloured stones in ancient times. During the 19th century, gem crystals were brought to Europe by traders, and further scientific study revealed more about their properties. European scientists marvelled at the ability of the crystals to polarize light and the pyroelectric properties of the mysterious stones, famously attracting ash particles when heated due to electromagnetic discharge. These brightly coloured crystals were found to share a geometric structure and from that point forward Western scientists referred to them as “tourmaline”. 

Watermelon Tourmaline. Image: Rick Dalrymple on mindat.org.

With additional study, it was revealed that not all tourmaline is created equal, and the gem was found to be a group of minerals that each have slightly different chemistry and may even grow together in series. There is a vast array of tourmaline minerals, but the stones most commonly seen in jewellery are elbaite tourmaline, schorl tourmaline, and dravite tourmaline, with small amounts of uvite tourmaline and liddicoatite tourmaline occasionally appearing on the market. These tourmaline minerals can grow side by side in the same location and can even mix within a crystal, so when used as gemstones they are often referred to as just “tourmaline” without specification of species. Many tourmaline minerals are capable of displaying multiple colours, which makes identifying them with the naked eye that much more difficult, but some tourmaline species are more easily spotted, such as schorl which is always black. 

Parti-colored tourmaline from Madagascar is fashioned into dramatic step cuts and freeform polished stones. Despite the similarities in their appearance, electron-microprobe data from the samples revealed that two were elbaite, three were liddicoatite, and three contained zones of both species (e.g., the kite-shaped stone on the bottom right). Image courtesy of Allerton Cushman & Co. via gia.edu; photo by Maha Tannous.

The complex structure of tourmaline gives all members of this mineral group a fair degree of hardness and high impact resistance making them that much more versatile in jewellery, and tourmaline’s varied appearance provides a nearly endless array of colours to utilize in bespoke designs. One tourmaline mineral is seen in jewellery more often than the others however, and that is elbaite tourmaline.

Elbaite tourmaline gemstones from Maine, USA. Image: ICA/ Boston Findings Co./ Gemological Institute of America

Learn more about elbaite tourmaline and its many colours in the next part of this series.

Tourmaline is the perfect choice for custom jewellery:

102.6 ct Peacock Carving Pink Tourmaline Matching Pair

2.49ct Lagoon Blue Tourmaline IGI Certified & 0.50ct Diamond Charm Ring in 14kt Yellow Gold

3.02ct Yellow Tourmaline Oval

 

© Yaĝé Enigmus