Opal, October’s Birthstone: The Unlucky Myth, and Everything Else Worth Knowing
If sapphire is the sensible one, opal is the stone that gets talked about in whispers. Unlucky, fragile, only for people born in October. Some of that is nonsense, some of it is half-true, and the rest is the reason opal has quietly become one of the most asked-about stones in the shop. Here is what we actually tell people.
1. The bad luck story is a nineteenth-century novel
For most of history opal was considered the luckiest stone going, because it seemed to contain the colours of every other gem at once. The Romans prized it above almost everything. The reputation collapsed in 1829 when Sir Walter Scott published Anne of Geierstein, in which a character wearing an enchanted opal comes to a bad end. Sales of opal in Europe reportedly halved within a year. Queen Victoria did her best to reverse the damage by giving opals to her daughters, but the superstition stuck, and you still hear it today. It has no basis beyond a plot device.
2. It isn’t a crystal at all
Most gemstones are crystals, with atoms arranged in a repeating pattern. Opal is different. It is hydrated silica, formed when silica-rich water seeped into cracks in rock and slowly dried, leaving behind tiny spheres of silica stacked together. In precious opal those spheres are all roughly the same size and neatly arranged, and it is the gaps between them that diffract light into the flashes of colour known as play-of-colour. Common opal, where the spheres are jumbled, has no flash and is far less valuable.
3. Water is part of the stone
Opal contains anywhere from three to twenty per cent water by weight. That is why it is softer and more delicate than most gems, and why the old advice about opal drying out and cracking has a grain of truth in it. Good quality Australian opal is stable and will happily last a lifetime. Some Ethiopian opal is hydrophane, meaning it absorbs water and can temporarily lose its colour or go cloudy when wet, then recover as it dries. It is worth knowing which you have.
4. Australia produces most of it, and Lightning Ridge produces the best
Around ninety per cent of the world’s precious opal comes from Australia. White and crystal opal comes largely from Coober Pedy in South Australia. Boulder opal, where a thin layer of colour sits on its natural ironstone backing, comes from Queensland. And the prized black opal, with its dark body tone that makes the colours blaze, comes almost entirely from Lightning Ridge in New South Wales. Fine black opal is genuinely rare and priced accordingly.
5. Ethiopia changed the market
Until the 2008 discovery at Wegel Tena in Ethiopia, opal was an Australian story. Ethiopian opal is now everywhere, and much of it is beautiful and good value. Two things to know: it is often hydrophane, as above, and it is sometimes treated, either smoked to darken the body or dyed. Neither is a problem if it is disclosed. Ask.
6. Doublets and triplets are not the same as solid opal
A doublet is a thin slice of precious opal glued to a dark backing. A triplet adds a clear dome of quartz or glass on top. Both are legitimate and much cheaper than a solid stone of the same appearance, but they should be sold as what they are, and a triplet in particular should never go anywhere near an ultrasonic cleaner, because the layers can separate. Look at the stone from the side: a solid opal shows colour through its depth, a doublet shows a flat straight line where the backing starts.
7. Hardness is around 5.5 to 6.5, so treat it accordingly
Opal will scratch if you are careless with it, and it will chip if knocked hard on an edge. That does not make it unwearable, but it does make it a stone for rings you take off to garden, wash up or go to the gym. Bezel settings, where a rim of metal wraps the edge of the stone, protect opal far better than claws. Pendants and earrings are the easiest homes for it.
8. Cleaning is simple, as long as you keep it simple
Warm water, a drop of mild soap, a soft cloth or very soft brush, and dry it gently. That is the whole routine. No ultrasonic, no steam, no household cleaners, no bleach. If an opal ring needs work done to the setting, tell the jeweller it is opal before they start, because the stone is usually removed before any soldering or heat goes near it.
9. Storage myths, and what actually helps
You will read that opal must be kept in water or oil. Please don’t. Stable Australian opal needs nothing more than a soft pouch away from direct heat. A locked car on a summer’s day, or a spot on a radiator shelf, is worse for opal than years of ordinary wear. If you own hydrophane Ethiopian opal, keep it away from perfume, lotions and soapy water, which can be absorbed and discolour the stone.
10. Why it is having a moment
Opal has spent the last few years turning up on red carpets and in serious auction results, and demand for it has followed. Part of that is the sheer individuality of the stone: no two are alike, and buyers who want something that is not a diamond have discovered that. Part of it is antique opal, which was hugely popular in the late Victorian and Edwardian periods and Art Nouveau jewellery, so there is a lot of lovely old material about. It is very much a stone that rewards seeing in person, under different light, in the hand.
Looking for an opal this October
We usually have opal in the shop across rings, pendants and earrings, including antique and second-hand pieces, and we are always happy to talk through solid versus doublet, Australian versus Ethiopian, and which settings will look after the stone. Come and see them move in the light.