Ancient Allure, Folklore and Formation of the Opal


The mysterious allure of this stone dates back to the time of ancient Greeks and Romans who cherished this gem considering it a symbol of hope and good fortune. Often called the Queen of Gemstones, a Roman scholar in 75 AD summed up their beauty when he stated:


“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 encompassed the red of ruby, the green of emerald, the yellow of topaz, the blue of sapphire, and the purple of amethyst.”


For etymologists, opallios is the Greek word for opals meaning to see a change of colour while the Roman term opalus means precious stone. As part of Greek folklore, this culture believed opals were formed from the tears of joy wept by Zeus after defeating the Titans and this victory bestowed prophetic powers upon him.


The fabled Greek god wasn't too far off when it comes to the creation of the opal which tends to be found near the earth's surface where ancient geothermal hot springs once flowed. Minerals bubbling up from underneath the earth's surface line the walls of cavities in bedrock and slowly over centuries have passed, these stones are eventually created.


Locations in the Land Down Under


While this precious stone can be found in many places all over the world including Brazil, Czechoslovakia, Ethiopia, Mexico and the state of Nevada in the USA, more than 90% of opals come from Southern Australia. Black opals, the rarest and most expensive of these gems come exclusively from Australia, especially those found in New South Wales.


These darker stones are mostly mined in the Lightning Ridge region of Southern Australia where hundreds of millions of pounds worth of these precious gems have been uncovered. In 2008, the black opal became the “Gemstone Emblem” for New South Wales and they're also found at open mining fields in Mintabie which is further north.


However, black opals aren't always the most valuable of these stones since there are many factors including brightness and colour patterns to consider. Generally speaking, darker opals have more carbon and iron oxide elements present inside them making the rainbow shades stand out much better compared to lighter ones.


The Precious Opal and Play-of-Colour


A "precious opal" is the title given to any opal that exhibits something known as "play-of-colour" according to geologists. Play-of-colour points to flashes of bright, colourful light a person sees when viewing an opal found in black, white, crystal, boulder and matrix versions of this precious stone. These colourful occurrences will constantly change when:

  • It is moved under a different light source,
  • As the light source is moved or
  • As a person changes their angle of viewing.


The opal is known as a mineraloid which is a material without a crystalline structure composed of tiny silica spheres that are translucent and transparent allowing the passage of light. In more common opals, the size of these spheres is arranged in an irregular pattern which scatters much of the light that enters the stone.


However, in precious opals, the spheres are similar in size, more precisely arranged in a regular, repetitive pattern. When the spheres appear in this type of a network landing in exactly the correct size and arrangement, light is diffracted inside of the stone showcasing its component colours. As light leaves a precious opal, it displays this "play-of-colour" giving it a unique beauty.


A Buying Guide Beginning With Body Colour


The base colour of any given opal is referred to as it's body colour and as mentioned previously, the darker the shade the more valuable the stone since it better showcases the reflective colours. From the standpoint of a buying guide, there is a scale in place for the body colours in opals that range from N1 as the darkest and most costly going to the other end of the spectrum of N9 as being more milky-white in colour and therefore less valuable.


Continuing with Translucence and Transparency


In contrast to body colour, the more translucent and transparent an opal is, the more valuable the gemstone becomes. Generally speaking, this type of transparency is divided into three categories from least to most valuable when you consider:

  1. An inability to see through the stone
  2. There is some transparency evident 
  3. The viewer is able to see through the stone


One of the easiest ways to check for transparency is by holding the stone against a light source and looking through the gem. How clearly you can see objects on the other side is one of the most basic ways of determining its translucency.


Natural Faults


Similar to other gems, often opals contain natural faults known as inclusions and not be be confused with a crack in the stone. An inclusion is a line inside the rock formation that forms against the grain. Inclusions can be found by holding the opal against a light using a microscope. As a rule, the locations and identification of inclusions should be performed by a jewellery professional.


Doublets and Triplets


Not to be confused with twins or the birth of three babies at once, doublets and triplets are techniques put into place that are designed to protect these gemstones from damage. Opals are notoriously brittle stones and when used in jewellery, protective layers are often put into place to safeguard them from potential cracking or breakage.


A backing layer is known as a doublet and can be the natural rough rock where the original opal came from, made from glass or obsidian. Another benefit of a doublet layer is the colours from the opal will become brighter due to the use of a darker background. When purchasing opal jewellery, the only way to ascertain whether or not there's a doublet in place is by removing the stone from its setting or asking the jeweller about its existence. 


A triplet is an additional protective layer placed over the gemstone using a clear cover like glass, plastic or crystal. The best-case scenario is when all three of them are utilised, a doublet underneath, the opal itself and the triplet on the exterior. Some jewellers will recommend this trio to protect this precious investment in order to safeguard your opal from potential harm.


Out-of-This-World Opal Jewellery


Another fun fact about opals, some of these jewels in their raw form was located on Mars making them one of the few gemstones discovered on another planet. When shopping for opals here on earth, the otherworldly beauty of these precious gems is showcased in many different ways. Here are a few examples of some beautiful options available for October's birthstone.


18ct Yellow Gold Opal Earrings


This lovely pair of stunning studs showcase two 0.98ct opal weight pear-shaped stones in a three claw setting of 18ct yellow gold. Donning these earrings is a wonderful way of adding a pop of colour to an outfit or ensemble.


18ct Yellow Gold Opal & Diamond Pennant


This pennant would pair nicely with the earrings outlined above. It also features a pear-shaped opal with two brilliant round cut diamonds suspended from an 18ct yellow gold 16" chain with a trigger clasp. The diamonds come in at one-half carat total weight and the opal weighs in at 0.88ct.


18ct Yellow Gold Opal & Diamond Ring


Our third choice also bears a striking similarity to the two other pieces highlighted previously. This three-stone ring is comprised of a central 0.61ct white oval opal in a four-claw setting. Flanked on either side by two brilliant-cut diamonds, with a total weight of 0.27ct on a polished, tapered band, this ring really rounds out any fine jewellery collection.


18ct Yellow Gold Opal Pendant


For gemstone purists, this 18ct yellow gold circular four claw set opal pendant includes a yellow gold tapered bale. At a weight of 0.66 and an affordable price of £650, the chain is sold separately with this choice.


Any of these options are available for purchase online and are able to be reserved for an in-store viewing at our location at 25 King Street. When shopping for jewellery, you don't need to go to the ends of the earth or even another planet to discover beautiful opals right here in Reading. 


If you have any questions about this precious gemstone or any type of jewellery, please contact us today. We're here to ensure you've got the very best options available from your local, independent and knowledgable provider.