Gemologist Lucy Reynaud, FGA DG GIA, explains why October has two birthstones, and why Opals have more to them than meets the eye.
October people are lucky and obviously deserving of many gemstones, because they have not one but two birthstones – Opals and pink Tourmalines.
I have a feeling that the reason for this doubling up on the birthstones for October is because the traditional birthstone, Opal, is one of those gemstones that people either love-love-love or really can’t stand. I use to be in the second category, until I learnt that there is far more to them than meets the eye, quite literally!
In reality though, throughout history, accepted birthstones rotated in and out, with style and availability sometimes determining which stones would reign. In 1912, the National Association of Jewellers standardized the list, and at that time Opal was the only birthstone for October.
The birthstone list was, however, updated in 1952 by the Jewellery Industry Council of America who added pink Tourmaline for October. The reason behind this thinking was that opals are technically a mineral, so an actual gemstone was needed too.
Despite the way Opals present, with random flashes of colour throughout the stone, these stones are incredibly structured gems. Under a microscope we can see that they are made up of billions of tiny silica spheres of different sizes, all stacked tidily one on top of the other. The seemingly random flashes of colour that we see some from the size of these spheres, and how they refract the light.
What is refraction, you ask? Well – the dictionary says that “the fact or phenomenon of light, radio waves, etc. being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density”.
What this actually describes is the way we see a rainbow when the sun shines through a piece of crystal – the white light goes into the crystal and is broken into separate waves of colour when it comes out again. The “Play of Colour” seen in Opals is the same thing – light goes into the gemstone, bounces off the miniscule silica balls and comes back to our eye as different colours of the rainbow – the colour we see depends on the size of the silica spheres within the opal. And if the spheres aren’t the right size then we won’t see any colour at all.
The amazing colours present in Opals have been praised since the beginning of written time – in fact as early as 75AD the roman scholar Pliny summed up opals by writing “Some opal carry such a play within them that they equal the deepest and richest colours of painters. Others … simulate the flaming fire of burning sulphur and even the bright blaze of burning oil.”
He marvelled that this kaleidoscopic gem, encompassing the red of ruby, the green of emerald, the yellow of topaz, the blue of sapphire, and the purple of amethyst. Since that time, Opal has routinely been called ‘The Queen of Gems’.
Australian black ‘Fireworks’ opal
In fact, the world Opal comes from Opallios, the Greek word meaning “to see a change of colour”. The ancient Greeks believed that opals were formed from the tears of joy wept by Zeus when he defeated the Titans… which isn’t too far from the truth, as Opals are actually formed when rainwater seeps down into crevasses in the rock. Once the water evaporates, the silica that is left behind dries out and hardens into precious Opal.
The most famous Opals come from Australia; in fact 95% of the world’s Opals are mined there. Other countries that also have Opals are Peru, Mexico, Ethiopia and Brazil. Opals from Mexico have recently started to be used more in jewellery too – they have a very different look to the Australian Opals, as instead of showing bright flashes of colour, they exude an orangey glow.
Mexican Fire Opal
Australian Opals are prized depending first on their background colour – many connoisseurs prefer a black background, as it shows the play-of-colour more vividly. The preferred play-of-colour is one that displays a wide range of colours. An Opal showing red, orange or green is technically a higher quality, although of course preferred colours also depend on the owner of the stone.
Opals are slightly fragile gems, with a Mohs hardness of 6. This means that if they are worn everyday in a ring, they will soon be covered in miniscule scratches and lose their polish. However, as a pendant, brooch or an occasional wear ring, they are stunning. Opals should not be stored in air tight containers, e.g. lock boxes or safety deposit boxes, as if they lose moisture, they will craze in a fine network of cracks that resembles a spider’s web.
These magical stones, with their kaleidoscope of colours, have been said to aid their wearer in seeing limitless possibilities.
Here at The Jewel Box, we would love to help you dream up limitless ways to create beautiful Opal jewellery. Call us on +65 6733 4100 to make an appointment.
Read more about the importance of choosing the right gemstone in our story: The story of our gemstones and how you should choose the right one.