October Birthstone: Our Exclusive Guide To Opal

Opal is a beautiful, rare and colourful gemstone that is the birthstone of those lucky enough to be born in the month of October, and also those under the astrological star sign Libra.

This one-of-a-kind October birthstone is found mainly in Australia, with the rarest type - the black opal - ethically sourced by small teams of opal miners deep underground in the outback town Lightning Ridge .

Australian opal is one of the most captivating gemstones in the world. From its mesmerising spectrum of vivid colours to its iridescence and ethereal properties, it is the most popular of all opals.

Here in our ultimate guide to opal, explore the fascinating world of this remarkable gem, its history and properties, and also celebrate those born in the month of October who are lucky enough to have an opal birthstone.


The word 'opal' is steeped in ancient history, originally deriving from the Sanskrit word upala meaning 'precious stone'. It is also said to originate from the Greek word opallios which translates to 'seeing a change of colour' - absolutely fitting for this amazing gemstone that is renowned for its 'play of colour'. Even the Romans had a word resembling opal - opalus - which means ‘to see a change of colour’.


Being October's traditional birthstone, opal is a highly symbolic, spiritually significant, positive and healing gemstone. And its properties are fascinating! Traditionally, and culturally, opal is said to be a symbol of good luck, love, passion, desire, fidelity, harmony and seduction. Folklore often says to wear an opal to enhance your optimism in life. For those born under the star sign Libra, it also represents purity and sincerity.

Opal is also said to be a stone of protection, giving the wearer cover against dangerous places, fevers and infections. It is believed to amplify existing traits, enhance self confidence, and help the owner realise their full potential. Also a stone of creativity, opals help stimulate originality and bring out the wearer’s inner light and spontaneity. October babies should feel special about being associated with such an amazing gem.

Wearing your birthstone is believed to bring luck and good fortune, so by wearing opal jewellery or carrying opal, October-borns can tap into amazingly positive energy, and feel secure, strong and empowered. Own your opal!

A range of opal jewellery from Black Star Opal


Opal is an ancient gemstone, formed millions of years ago when rain soaked the earth in desert locations throughout central Australia. As the rainwater penetrated the ground, it deposited a dissolved mineral called silica through cracks in underground rocks. After the rainwater dried up, layers of tightly packed spherical silica deposits were left behind, forming opal. 

In science terms, opal is a hydrated amorphous form of silica, with a water content ranging from 3% to 21% by weight (some incorrectly believe solid opals can not get wet, which is untrue, but it's still advised to keep them away from hot water). 

It is the only gemstone on earth known to display a really cool, unique phenomenon called 'play of-colour,' or iridescence. This spectral phenomenon, as well as opal's amazingly beautiful patterning, is caused by light refracting and diffracting in the voids between opal's silica spheres. Different size spheres result in different colours. 

Opal Cuts, Colours and More!

You might have purchased your first opal or decided on a piece of jewellery to celebrate your birthstone. Either way, it's important to know a little about this remarkable gemstone and the factors that go into its value. While many people know about diamond's 4Cs - cut, colour, clarity, carat weight - you might be surprised that the same 4Cs are just as important with pricing an opal - plus some special extras! One thing's for sure, opal is a lot harder to grade than diamond thanks to its many variables and complex classification system. We cover some of these below.


The most common cuts and shapes for Australian opals include cabochon rounds and ovals, as well as marquise, pear and heart shapes. A cabochon is a very old style of cutting a gemstone, and was the first type of gem cut before faceting became the preferred cut (faceting opals is usually a no-no as the cut doesn't benefit the gemstone). Traditionally shaped stones are usually deemed more desirable than freeform shapes, with the exception being boulder opal where this flowing, organic shaping is highly prized.


As mentioned previously, all precious opal has an iridescent, rainbow-like appearance due to its play of colour, which is created by diffraction and interference of light through the stone's many layers of silica spheres. The most valuable and rarest colour is intense red, especially in a black opal, which is highly sought after and known by the opal industry as a 'red on black' stone. Blue is the most common colour and thus a stone featuring only this hue would typically be priced lower than stones displaying other colours such as green, pink, yellow and orange.

The direction of the colour in an opal is also important, as its appearance does change depending on how you view the stone. 'Facing' refers to when an opal looks its brightest, and depending on how many directions the stone 'faces', its value increases or reduces. How many directions the stone 'faces' determines what type of jewellery it's suitable for, and a jeweller will consider the direction of colour when setting the stone.


Opal patterns are also part of its unique characteristics and a pricing factor, with rare types such as harlequin, flagstone or Chinese writing, and more common patterns like rolling flash or chaff. When you look closely, more than one type of pattern can be seen in an opal, and when this occurs valuers would list the dominant pattern first and then the secondary pattern in their valuation report.


Body tones in an opal range from opaque, as seen in a black, boulder or white opal, through to completely transparent, as with a crystal stone. Experts place value on body tones when grading opals, especially when free of any visible inclusions, fractures, or host rock (called matrix). Each type of opal should possess the optimal background to display the brightest, most beautiful colours and patterns possible. Clarity is also important, and a stone that has a cloudy, murky background is not only unattractive but could possibly signal an internal instability.  



Found mainly at Lightning Ridge in outback Australia, black opal is known as the most rare and valuable type of opal on earth. Black opal features a rich and vibrant colour spectrum set against a dark, opaque body tone, making it the opal of choice for some of the world's best jewellery collections and designers.


Precious white or light opal usually contains softer, more pastel colours than black opal, and is also known as milky opal. A white opal's body tone ranges from opaque to translucent, and Coober Pedy in South Australia is the world's biggest supplier of this type of natural gem.


Crystal opal has a translucent, light body tone, similar to glass or rock crystal, so when held up to the light, some light can be seen passing through. This type of opal can also have a black or dark transparent body tone and is called dark crystal. Crystal opals typically display an attractive and  colourful iridescence.


Similar to black opal in appearance, colour rich boulder opal is mainly found in Western Queensland, forming in cracks and cavities inside 'boulder', which is brown-red coloured ironstone often included on the back of the polished gemstone. Boulder opal's popularity has soared in recent years with high end jewellers thanks to its vivid hues and unique, freeform shaping.

A woman wearing a range of white gold opal rings on her hand which is held up against her hair


Because October's birthstone is so versatile in colour, shape and form, there's definitely no shortage of stylish opal jewelry options available. From delicate earrings to bold necklaces, you're sure to find the perfect piece for you. Wearing opal jewellery, like opal earrings or an opal pendant, close to the face is believed to assist with eye disease, emotional stability, and memory. While  wearing an opal ring is said to promote blood purification, help kidney function and PMS, ease childbirth and support the immune system.


When it comes to settings, four-pronged claw settings are very popular, as are bezel settings, especially for modern, contemporary designs. Bezel settings can be a better choice for opal rings as there is less chance of knocking and damaging the stone. Opals can also be channel set, with the centre stone firmly secured between two bars of precious metal, creating an unassuming yet sophisticated look.

You should consider your lifestyle when deciding on the right setting, as if you're wearing an opal birthstone throughout the day and you're more active, a bezel set piece of opal jewellery is probably better for you. On the other hand, if you plan on wearing it only at night as dress jewellery, then claw settings will allow for more light to hit the gem making it more sparkly and gorgeous.


Opals are precious gems and require special care and attention to ensure they always look clean and fabulous. To prevent accidental scratches when cleaning, we recommend using a soft cloth or brush with warm soapy water, and definitely no abrasive cleaners. Never submerge a doublet or triplet opal in water for a prolonged period of time, as water can penetrate the glued layers and your triplet can end up looking cloudy (we recommend all triplet opal rings be worn as dress rings only).

Also don't store your opal under harsh, direct light as it could dry it out internally and cause crazing or cracking. So keeping them safe in cool, dark places such as a jewellery box, pouch or even a safe is best when not wearing them. Some people keep their uncut opal, known as 'rough', in water or even baby oil!


So whether you're born in October, looking for a unique gift for an October birthday, or want a stunningly beautiful gemstone for a special occasion such as an engagement or anniversary, opal really is the perfect choice. Captivating, mysterious and unique - opal is sure to add some sparkle to any occasion, as well as being spiritually significant for those with an October birthstone. So don't wait another moment - celebrate with your own opal gemstone today!