Overview
About Tourmaline
Tourmaline’s colours have many different causes. It’s generally agreed that traces of iron, and possibly titanium, induce green and blue colours. Manganese produces reds and pinks, and possibly yellows. Some pink and yellow tourmalines might owe their hues to colour centres caused by radiation, which can be natural or laboratory-induced.
Birthstones & Anniversaries
Tourmaline is a birthstone for October, along with opal. Tourmaline is also the gem of the eighth anniversary.
1554
Francisco Spinoza’s expedition discovers “Brazilian emerald”: the first recorded green tourmaline crystal.
Pyroelectric
Tourmaline becomes electrically charged when heated. Also when squeezed: it’s piezoelectric too.
Paraiba
Brazilian source famous for vivid blue to green tourmalines coloured by copper.
Facts
-
Mineral:
Tourmaline
Chemistry
Treatments
There are a number of processes used to alter the colour or apparent clarity, or to improve the durability of gems.
Learn MoreSynthetics
Some gemstones have synthetic counterparts that have essentially the same chemical, physical and optical properties, but are grown by man in a laboratory.
Learn MoreImitations
Any gem can be imitated – sometimes by man-made materials or by natural materials chosen by man to impersonate a particular gem.
Learn More
Why We Love This Gemstone
Trigonal System
Tourmaline crystallizes in the trigonal system; no other common mineral has three-sided prisms.
Watermelon Variety
Watermelon tourmaline is green on the outside and a delicious pink on the inside.
Liddicoatite
Liddicoatite tourmaline was named for beloved former GIA President Richard T. Liddicoat.
Quality Factors
Tourmaline’s varieties have a wide range of quality factors considerations.
Colour
Tourmaline's rainbow colours have a wide range of colour intensity and tone.
Clarity
Pink to red tourmaline often has more visible inclusions than green to blue varieties.
Cut
Tourmaline crystals are often long, leading cutters to cut slender finished stones.
Carat Weight
Tourmalines come in all shapes and sizes. The value change for size varies with the variety.
Tourmaline Quality Factors: The Comprehensive Guide
Research
Explore sources, gemmological research and the role of gems in history.
Expedition to the Cruzeiro Tourmaline Mine in Minas Gerais, Brazil
Andrew Lucas, Duncan Pay, Tao Hsu, Shane McClure, and Pedro Padua , Nov 7, 2014 Read ArticleSolution-Generated Pink Colour Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines from Mozambique
John I. Koivula, Kevin Nagle, Andy Hsi-Tien Shen, and Philip Owens Read more in English
