Afgan Tourmaline lot 298.25cts
Originally uploaded by facetssrilanka.
Tourmaline belongs to the trigonal crystal system and occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section. Interestingly, the style of termination at the ends of crystals is asymmetrical, called hemimorphism. Small slender prismatic crystals are common in a fine-grained granite called aplite, often forming radial daisy-like patterns. Tourmaline is distinguished by its three-sided prisms; no other common mineral has three sides. Prisms faces often have heavy vertical striations that produce a rounded triangular effect. Tourmaline is rarely perfectly euhedral. The word tourmaline is a corruption of the Sinhalese word turamali, meaning “stone attracting ash” a reference to its pyroelectric properties.
Tourmalines are found almost all over the world. There are major deposits in Brazil, Sri Lanka and South and south-west Africa. Other finds have been made in Nigeria, Zimbabwe, Kenya, Tanzania, Mozambique, Madagascar, Pakistan and Afghanistan. Tourmalines are also found in the USA, mainly in Maine and Utah.
In the Treasure’s Trove of gemstones, the tourmaline is very special. Its high availability and its incomparable colour spectrum make it one of the most popular gemstones in the world.
