The birthstone associated with October is the beautiful and unique opal.
Opal is famous for its shimmering display of rainbow colours. This is due to its structure: opal is formed of a mass of sub-microscopic spheres with tiny gaps between them. As rays of light hit the gaps they are split slightly. This process, occurring multiple times across the entire stone, means that we see distinct colours across the surface. This effect, known as ‘play-of-colour’, does not occur in all opals; it is particular to the variety called precious opal. Other varieties include the beautiful transparent fire opal, named for its burning yellow to orange-red hues, and common opal; an opaque stone that is popular in pastel shades of blue, green and pink.
Until the late nineteenth century opal was sourced from central Europe, but the discovery of the extensive opal fields in Australia brought more of it to the market. Australia quickly became the world’s largest supplier of opals, and remains so to this day, although since 2008 beautiful stones have also been available from Ethiopia.
Opals have an interesting history: we are often told that they are bad luck, but for many centuries they were regarded as the luckiest of all gemstones. Their ability to display a beautiful rainbow of colours meant they were thought to possess all the virtues of the various coloured gems in a single stone. Most sources trace the association with bad luck to the novel ‘Anne of Geierstein’ by Sir Walter Scott. Published in 1829, the novel was a bestseller in its day. It featured an opal talisman said to have supernatural powers. The stone lost its colour on contact with holy water, and soon after its owner died. Within a year of the novel’s publication opal sales across Europe had fallen by 50%, and took decades to recover!
Whether you believe in the superstitions surrounding opal or not, it is worth bearing in mind that it is more delicate than many other popular gems. It is relatively soft and is susceptible to damage from acidic substances such as cleaning products or cosmetics, so we would recommend removing your opal jewellery during housework or gardening. Because it is fragile, opal is often set as composite pieces with additional protective materials covering the opal at the front and back; these are known as doublets or triplets depending on how many layers are used. If you would like to know more about this, or how to care for your opal jewellery, our experienced team of gemmologists will be happy to help you.
We stock a range of opal jewellery in our showroom. Unfortunately, its complex colours mean it does not photograph well, but a small selection is available to browse on our website.