We know opals as one of the October birthstones and as intrinsically Australian - so much so that it is our official national gemstone. Whilst other countries produce opal of varying quality and colour, Australian stones are the most desirable and make up approximately 95 per cent of the opal found today.

Gem quality opal consists of tiny silica spheres packed tightly together. Opal’s play of colour is due to the arrangement of these spheres breaking white light into separate colours. Some of the prettiest opals resemble Impressionist landscapes, and whilst all colours are beautiful, an opal displaying red flashes is most highly prized.

Mined in Australia, from the mid to late nineteenth century, are the white or light precious opals from Coober Pedy and Andemooka. With a milky appearance overall, they exhibit stunning patches of colour from violet to blue through to green, yellow, orange and red.

Lightning Ridge is best known for its black precious opal, first discovered at the beginning of the twentieth century, which can be valued as much as the best diamonds and rubies. The colour play in a black opal is greatly enhanced by the dark background. Both black and white opals are most often cut as cabochons, with a domed top.

Fossils of Lightning Ridge above.

Also sought after is the Queensland boulder opal which has a layer of solid brown ironstone remaining on the back of the opal. Veins of colourful opal form in the cracks of large boulders under the ground. Boulder opals can display any colour of the rainbow. Due to the layers of opal being thin, most boulder opals are cut and polished with flat tops.

Opal can be found in antique jewellery from the Victorian and Edwardian eras through to Art Nouveau and Art Deco pieces. Queen Victoria enjoyed wearing opals and was known to gift them to family and friends. Small round and oval cabochons were used as accents in pretty, nature-inspired brooches and pendants, highlighting details such as a bird’s eye or a flower stamen. An opal three or five stone Victorian half hoop ring is a classic piece still being worn and in demand to this day.

The famous French artist and jeweller, René Lalique, featured opal in some of his most well-known masterpieces of the Art Nouveau period. He combined enamelling and other precious stones, with opal, to bring his dragonflies, nymphs and flora to life.

A "Carnation Brooch" by René Lalique, circa 1900-1902 to the left and a René Lalique gold, carved opal, enamel and aquamarine dragonfly bracelet to the right.