Tourmaline (Green)

Green Tourmaline (Verdeltia) Green tourmaline is also known as verdeltia “greenstone”: all shades of green. Tourmaline has both pyroelectric and piezoelectric properties. This means that opposite charges accumulate both under pressure and when heated. Tourmalines were introduced in western and central Europe in 1703 by the Dutch who imported it from Ceylon. The biggest admirer of the tourmalines was Tzu Hsi[wiki], a widow empress who ruled China from 1860 to 1908.

The empress used the stone as a notch, on watch chain pins, or on the jacket buttons of the Imperial Court. It usually polychromy within the same mineral, usually in longitudinal form and its colors vary according to the presence of different elements. Its transparency varies in different degrees until it reaches the opaque. It is of little or no exfoliation, which is the property of splitting or separating into crystals of similar faces. Tourmaline has piezoelectric properties, which make it a mineral with various uses in the industry.

It is of magmatic origin – to a lesser extent in igneous rocks – and we usually find it in rocks called plutonic. Tourmaline is the only mineral capable of generating electricity and this capacity has a lot to do with the shape of its crystals. Its elongated and prismatic shape of the hexahedral type allows two crystals, the negative and the positive, to form in its crystals. When subjected to some pressure, for example, heat, the ions distributed throughout the mineral are sorted at the poles, at one end the positive and at the other the negative. This exclusive property has another peculiarity: this electricity generation occurs in two moments, when we apply pressure or when we remove it, that is to say, that the sudden changes in temperature trigger this property in the tourmaline.

It has been proven that by dividing the tourmaline crystals their piezoelectric properties remain unchanged.