The Fine Jewellery, Watches and Silver Sale on 12th July will include some beautiful examples of Opal jewellery. Here we look a little closer at this fascinating stone.
An Opal and Diamond Cluster Ring (Estimate: £3,000-5,000 plus buyer's premium)
Opals are an incredible and unusual gemstone. The only gemstones capable of showing multiple hues of colour at the same time, they have carried the superstitious burden of being unlucky, but this fascinating gem deserves a better reputation! The ring pictured above is an unusually large jewel, the opal itself is approximately 23mm long, and it is estimated that there is over 6 carat in total diamond weight accentuating this impressive piece.
Opals are composed of a hardened silica gel, which contains up to 10% water. The fact that they are non-crystalline, unlike other gems, and have a high water content means that they can dry out and even crack. Some people believe that this is where the “unlucky” moniker may have originated.
An Opal and Diamond Cluster Brooch/Pendant on Chain (Estimate: £1,000-1,500 plus buyer's premium)
The mesmerising shifts of colours are created by the structure of the gem. Tiny silica spheres within the opal diffract light. Some opals look fairly white and opaque and do not exhibit much play-of-colour or iridescence, but when the aforementioned silica spheres are larger, more colours can be seen.
An Opal and Diamond Pendant on Chain (Estimate: £700-1,000 plus buyer's premium)
Red flashes in the iridescence are coveted, and the blue and green hued opals are more sought after than those with a white base colour. An Early 20th Century Opal and Diamond Bar Brooch displays some beautiful red flashes of colour, within what is a very colourful gem.
An Early 20th Century Opal and Diamond Bar Brooch (Estimate: £600-800 plus buyer's premium)
The nature of opal means that it suits a cabochon cut, which is polished and slightly domed. It is a soft stone, known for its sensitivity, so cutting or carving in a more traditional style is highly skilled work, but doesn’t always display the interesting colour effects that opals are known for. However, the opal, onyx and diamond ring features a cushion cut opal, to great effect.
An Opal, Onyx and Diamond Ring (Estimate: £2,000-3,000 plus buyer's premium)
As well as being a soft stone, and one that ideally should not be allowed to dry out in case it fractures, opals are also porous. Therefore, contact with liquids, hand soaps, creams, perfumes or chemicals of any sort should be avoided. The best way to clean an opal is with a soft dry or damp cloth, not with jewellery cleaners. Excessive heat or humidity could also affect the stone, either by causing damage, or a change in colour.
A 9 Carat Gold Opal Ring (Estimate: £2,000-3,000 plus buyer's premium)
