What is Tourmaline
Tourmaline is a kind of semi-precious stone which has a Mohs hardness of 7 to 7.5. Its name means mixed gemstone in Sinhalese. Tourmaline has properties of piezoelectricity and pyroelectricity; it can obtain slight electricity through electrostatic effect. Tourmaline has lots of colors, sometimes it even gets two or more colors on the same crystal; the color of Tourmaline mainly caused by types of metal elements inside it.
Types of Tourmaline
The Tourmaline we commonly encounter can be divided into three types:
SchorlIt contains sodium and iron and appears in black and brown. Schorl is the most common Tourmaline.
DraviteThe color of this kind of Tourmaline is dark yellow to brown with sodium and magnesium in it, some Dravite are green. Brown tourmaline is another name for Dravite.
ElbaiteElbaite contains lithium, sodium, and aluminium; the color are red, blue or even colorless. If red and green appear on the same crystal, there is a special name for it called Watermelon Tourmaline.
History and Legend of Tourmaline
- In the year 1703, some children in Amsterdam were playing with the stones that brought back from sailors. They observed the stones not only seemed colorful under the sun but also attracted or repelled small things like dust and weed, due to this phenomenon Dutch people named the stone as ash-drawers. Later, scientists discovered that ash-drawer became charged once it was heated or be rubbed, with this discovery, Tourmaline got another name called electricity stone in Chinese.
- The usage of Tourmaline in China can be traced back to Tang dynasty, Emperor Taizong of Tang made his imperial seal out of Tourmaline. Empress Dowager Cixi had a great passion for Tourmaline, she had lots of Tourmaline jewelries and Tourmaline can also be found in her mortuary objects, some of her jewelries can be seen in National Palace Museum in Taipei.
Application of Tourmaline
Since the properties of Tourmaline were found, Tourmaline was used in different ways other than just jewelries. During World War II, Tourmaline was utilized as a tool to detect the pressure of nuclear explosion, nowadays we make manometers with Tourmaline due to its piezoelectricity. People study Tourmaline to make clothes, makeups, skin care masks and other products, commodities that contain Tourmaline can be found on the market, too.