Opal occurs in many forms, the most common of which are referred to as precious opal (intense plays of different colours), fire opal (named after its orange colour and often displaying a “fire” of other colours), and common opal, (usually opaque and showing no other play of colours). The stone is actually a hardened silica gel containing 5-10% of water. The often, startling iridescence of precious opal, the least crystalline of the opals, is caused by the difraction of light on a regular arrangement of tiny, transparent , silica spheres with water in the intervening spaces. The larger the silica spheres, the greater the range of colour in the stone.
95% of the worlds best opals now come from the minefields of Australia. Lightning Ridge, White Cliffs, Coober Pedy and Andamooka have some of the most famous deposits. Previous to the Australian discoveries, Slovakia supplied the best quality opals. Today they are also found in Brazil, Guatemala, Mexico, Indonesia and Russia.
Known since antiquity, opal derives its name from the Roman word “opalus”, a Latinized version of the old Sanskrit “upala”, meaning precious stone. There are many legends and tales that surround this colourful gemstone full of fire and lightning. Back before memory itself, in the Ancient Dreamtime of the Australian Aborigine, it was told that the creator came down to earth on a rainbow, bringing a message of peace to all mankind. At the spot where his foot touched the ground, the stones became alive and began to sparkle with all the colours of the rainbow. And, so were opals born. Until the discovery of the Australian opal fields in the 19th century, opals were a relatively rare stone, although, they were known and used by the Romans. They only became widely used however, with the New World discoveries, the Art Deco movement and the mass cutting of the stone by the Iber Oberstein stone cutters in the first part of the 20th century. Given the sometimes fragile nature of the structure of the opal (it is not the hardest of stones and given its water content and crystalline nature it can dry out and possibly crack under certain conditions), attempts have been made to strengthen the stone by making doublets and triplets. The former have a layer of natural opal attached to a strengthening piece of black onyx or other tougher stone, and the latter is a sandwiched piece of natural opal between a piece of black onyx on the bottom and a transparent piece of rock crystal on the top. In our birthstone jewellery range we use AA grade opal triplets from Australia.
Opals have always been attributed with healing powers. They are said to be able to cure depression and to help the wearer find true love! Opal is the birthstone for October.