One of nature’s most vivdly coloured gem treasures.
Not a particularly well known gemstone, Diopside (or sometimes known as Russian Diopside) was first described in the early 1800s and derives its name from the Greek words “dis and “opse”, meaning “two faced”, in reference to the two ways of orienting the gem before cutting (Diopside is unusual in that it has perfect cleavage in two directions).
Due to the presence of iron, the colours of the gem vary from yellow to pale green to dark bottle green. Two of the most popular varieties are Black Star Diopside (normally cabochon cut if the gem demonstrates chatoyancy or asterism) and Chrome Diopside which, as the name suggests, gets its vivid green colours from chromium.
Many people believed that this gem would only ever be found in a green colour. However, in Italy it has been found in very small deposits to be blue, where it is also referred to as Violan.
Diopside forms in metamorphic rocks and the crystals are short and columnar, with a square or 8-sided cross section. It has a hardness of 5 – 6 on the Mohs scale; though this is fairly soft when compared to other gems, it is extremely durable once set in jewellery.
The main deposits for Chrome Diopside are in Southern Siberia, Russia and many people in the trade now refer to it as "Russian Diopside" - after all, chrome is associated with old-fashioned car bumpers! The mines here are located in very remote areas where, due to snow and freezing conditions, miners can only gain access to the area for a few months each year. In 2010 fewer miners than normal returned to the area and as I write this piece I am still awaiting news as to what has happened this year. To make matters worse, Russian Diopside has become very popular in mainland China, so right now we are experiencing massive price rises for this gem as the supply has reduced whilst the demand has increased. The gem is also mined in very small quantities in Sweden, Germany and the USA.