Tourmaline’s name comes from the Sinhalese words tura mali, which mean “stone of mixed colors.” It has this name as it can be found in many colors. It is not made of one mineral but a complex group of minerals with different chemical compositions and physical properties. The gem falls under different sub-categories depending on what trace elements are present.
Some varieties include:
- Elbait which comes in three subtypes: Black tourmaline, known as “schorl” is rich in iron and produces dark shades from deep brown to bluish black. This the most common variety. Dravite or brown tourmaline is rich in magnesium and produces colors ranging from brown to yellow. Fluor-liddicoatite has a high concentration of Calcium but can be smoky brown, but also pink, red, green, blue, or rarely, white. These gems can have multiple colors within one gem, this is due to changes in the solution during crystal growth.
- Rubellite, or Red Tourmaline, has a high concentration of Manganese which gives it a reddish color. If the color is less vibrant in different types of light, it may be called pink tourmaline.
- Indicolite, or blue tourmaline, can have a purplish blue or bluish green hue, depending on the amount of iron and titanium contained within.
- Verdelite, or green tourmaline, sometimes resembles emerald. If it has chrome and vanadium in it, it’s called a chrome tourmaline instead.
- Achroite or colorless tourmaline is rare.
- One of October’s birthstones.
- It can become electrically charged through heat (pyroelectricity) and through pressure (piezoelectricity).
- Chemistry: Has many possible mineral makeups.
- Sources: GIA.edu, AmericanGemSociety.org, Wikipedia.org