The opal gemstone is considered to be the birthstone for people born in the month of October.
Considered a delicate, soft stone, each opal is unique, either classified as a common opal, or precious opal, depending on the shape, size and arrangement of the silicate spheres within the stone. The colour of an opal will also depend on the angle of the spheres, and as well as colourless, opals may be black, yellow, red, green or blue.
Fire opals, often translucent, are found in a variety of colours, from pale yellow to deep red, mined mostly in Mexico; the darker the colour of the stone, the more valuable the fire opal. Black opals, said to represent harmony, are incredibly rare and are only found in Australia.
The word opal is thought to derive from the Sanskrit word upala, meaning precious stone and the Greek word Opallios, which means a change in colour. The Romans would carry opals with them as a lucky talisman, as they bore the colours of the rainbow. Additionally, since 1993, the opal is the national gemstone of Australia as it is believed to have been born from rainbows, and Australia mines more opals than anywhere else in the world. The most expensive opal is the 1956 Olympic Australis, named because of the Olympic Games which were taking place in Melbourne at the time. The 17,000-carat stone is estimated to be worth $1.9 million. Thanks to the array of colours, the opal is believed to be good for creativity. It also symbolises hope and truth. Favoured for its unique unpredictability, it can take up to six millions years for 1cm of opal to develop.
To celebrate 14 years of marriage an opal is the gemstone which is traditionally given as a gift, perhaps either in the form of a statement necklace or a ring, set in a silver, white gold or platinum.