Friday, 16 December 2016

Goshenite

What is Goshenite?

Goshenite is the white to colourless variety of Beryl. Beryl is best known for its gem varieties Emerald and Aquamarine, as well as the lesser known Heliodor and Morganite, but the variety Goshenite less frequently used as a gemstone being that it lacks the colour appeal of the other varieties.
Since all these colour varieties are caused by impurities and pure beryl is colourless, it might be tempting to assume that goshenite is the purest variety of beryl. However, there are several elements that can act as inhibitors to colour in beryl and so this assumption may not always be true. The name goshenite has been said to be on its way to extinction and yet it is still commonly used in the gemstone markets. Goshenite is found to some extent in almost all beryl localities. In the past, goshenite was used for manufacturing eyeglasses and lenses owing to its transparency. Nowadays, it is most commonly used for gemstone purposes and also considered as a source of beryllium.
The gem value of goshenite is relatively low. However, goshenite can be coloured yellow, green, pink, blue and in intermediate colours by irradiating it with high-energy particles. The resulting colour depends on the content of Ca, Sc, Ti, V, Fe, and Co impurities.

History

Named for its major discovery in Goshen, Massachusetts, USA, Goshenite is the purest form of Beryl, containing fewer impurities than the coloured varieties. It is an aluminium beryllium silicate mineral that forms in prismatic or vertically striated crystals, sometimes terminated by small pyramidal faces. It is transparent to translucent, with a vitreous luster. Though the gem value is relatively low, it is most commonly used for gemstone or metaphysical purposes, and considered as a source of beryllium. 
While Goshenite is the colourless variety of Beryl, the Beryl family also forms in other colours used as gems, such as green Emerald, blue Aquamarine, yellow Heliodor and Golden Beryl, Red Beryl or Bixbite, and pink Morganite. Used in combination, Goshenite enhances the energies of all Beryls and increases their healing and transformative properties.
Goshenite was first discovered in the small town of Goshen, located in Hampshire County of Western Massachusetts. Today, goshenite and other deposits of beryl, can be found all around the world. Before the introduction of synthetic diamonds, goshenite was often used as a diamond alternative. By the placement of silver or green foil under the stone, goshenite can even be used as alternatives for emeralds and other precious coloured stones. The coloured foil enhances goshenite's colour similar to the way 'coating' can enhance mystic quartz or topaz.
Goshenite was once used for the manufacturing of eyeglasses, because of its excellent transparency. Goshenite is also considered an excellent source for beryllium. Goshenite, like all beryl, has excellent hardness, durability and toughness. It is very resistant to corrosive materials, but goshenite is considered to be quite brittle and sensitive to pressure.

Identifying Goshenite

There are a number of different gems that closely resemble goshenite, including quartz, white topaz, white zircon and white sapphire. However, beryl can usually be easily distinguished from other similar gems through basic testing. One of the easiest testing methods to identify goshenite is by testing for specific gravity (density) and hardness. Goshenite is significantly harder than quartz and feldspar, but slightly softer than topaz and sapphire. Beryl, topaz and sapphire all have very different crystal structures, making beryl quite distinct due to its unique six-sided hexagonal crystal formation.

Goshenite Origin and Gemstone Sources

Although goshenite is named after the small town of Goshen, Massachusetts, it can be found all over the world including North and South America, China, Canada, Russia, Mexico, Colombia, Brazil, Northern Europe, Africa and Asia. It is thought that the largest, cleanest and best quality material is found in Brazil.

Properties of Goshenite

Chemical FormulaBe3Al2SiO6
ColourWhite, Colorless
Hardness7.5 - 8.0
Crystal SystemHexagonal
Refractive Index1.57 - 1.58
SG2.6 - 2.8
TransparencyTransparent
Double Refraction.006
LusterVitreous
Cleavage3,1 - basal
Mineral ClassBeryl