Gossamer Beauty: Opals

Beautiful, mysterious opals... these very unique gems are top of the scale when it comes to superstitions associated with precious stones. They are traditionally the birthstone for October and their multi colour light refracting properties have inspired devotion and irrational fear in equal measure through the ages.
First, the science bit... Opal is formed by minute crystals of hydrated silica. Silica gel fills crevices in rocks; the water then evaporates and leaves behind a crystal structure of miniscule silica spheres which diffract the light into many different colours. This is why opals are always cut en cabochon, as it is the only cut which can fully show this rainbow display of light to its full advantage. The orange variety of opal, called fire opal, is mainly orange and does not exhibit the play of colour of other opals, except with the occasional green flash, so I am sticking to the rainbow variety for this article. Because of the way they are formed, they can contain up to 20% water. I once saw a fascinating stone at a gem fair containing an unchrystalised bubble of water.
Experts consider black opals to be the finest- against the dark background, the play of colour is much more prominent and therefore a more opaque stone is more highly prized. With white opals, more transparency adds more value, as the rainbow effect through the translucence of the stone renders the gem almost dreamlike. As with other gemstones, good quality ones should be blemish and inclusion free and show no sign of the host material. Exceptional stones should also be symmetrically cut. The finest stones in the world famously originate from Australia, which produces some 95% of the world’s gem quality opals.
If you are considering buying one, beware of doublets or triplets: this is where a very thin slice of the gem has been backed with something more commonplace and sometimes topped with clear varnish. It is easy to observe just by turning the stone sideways and seeing the layers. Opals are also quite fragile. On the Moh’s scale, they only measure 5-6.5 hardness, the same as emerald. This fissile quality has done little to dispel the unlucky reputation around them.
This brings us to the superstition bit... the Romans prized opal above all precious stones as they contain all the colours of the rainbow. This reverence remained through to the Middle Ages and beyond, as opals were believed to convey the properties of all the stones whose colour was represented in the opaline spectrum. The unlucky bit came in the Victorian era and was entirely due to Walter Scott’s novel ‘Anne of Geierstein’ in which the gem plays a sinister part. Opal sales dropped 50% in the year after its publication and remained low for some time after that.
They had a major resurgence in the 1890s with the coming of Art Nouveau. The movement appreciated materials for their artistic rather than intrinsic value. Artist jewellers such as Henry Vever and René Lalique were highly preoccupied with rendering nature with their pieces and opal’s translucence and play of light were ideal in the representation of gossamer like insect wings, feathers, water patterns and flower petals. In conjunction with the opalescent qualities of enamel, moonstone and labradorite it was a winning combination and a refreshing antidote to the platinum and diamonds of the Garland Style of the Belle Epoque.
Opals fell out of favour again, but with the resurgence the new naturalistic movement in jewellery in the last 10 years, they have found favour with established maisons and artist jewellers alike. Boodles produced a stunning peacock feather necklace recently with an important black opal set in the eye of the feather with an important black opal set in the eye of the feather and Van Cleef and Arpels used them extensively in their Atlantide collection; Wallace Chan finds them the perfect material for some of his more dreamlike creations. I hope that their new found popularity goes a long way in dispelling the unfair reputation of this misunderstood stone.