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Gemstone of the Month: October

October’s gemstone can only be the incomparable Opal!

Goddess of the Rainbow, trapped lightning or bringer of invisibility, one of Nature’s galactic wonders – and not just found on Earth …!

In a cave in Kenya, an anthropologist, uncovered the earliest known opal artefacts. Dating back to about 4000 B.C., they most likely came from Ethiopia.

Opal is a hydrated form of silica, composed of spheres arranged in regular, closely packed planes.  Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals.  Precious opal shows a variable interplay of internal colours visible when light defracts from these spheres.  Depending on the conditions and minerals present when it formed, its colours can range from clear to white, grey,  red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black.  Of these, black opal is the rarest with white and greens being the most common.  Opals vary in optical density from opaque to semi-transparent and show ‘opalescence’, a form of iridescence.

Opal was rare and very valuable in antiquity.  With its only known source being ‘Cervenica, beyond the Roman frontier in Slovakia’, it was prized in Europe by royalty and acquired almost exclusively for their use; that is until vast deposits were discovered in Australia in the 1800s.

The word 'opal' has some hotly debated origins.  Many modern references suggest it comes from the Sanskrit word úpala which means ‘precious stone’.  Yet others claim is that it comes from the Latin Opalus; or the Greek Opallios which both mean ‘to see a colour change’ or ‘precious stone’.  One further possibility appears in a reference to the gem made by Pliny the Elder who opined it may have its origins in the name Ops; who was the wife of Saturn and the goddess of fertility!

The ancient Greeks thought opal to be the tears of Zeus and prised it as highly as diamonds. The ancient Romans wore opal as a symbol of hope and purity and believed it could cure illness. In ancient India, opal was referred to as the Goddess of the Rainbow, turned to stone. Ancient Arab cultures believed opal had fallen from the sky and that the play of colour was trapped lightning. According to Arab lore, opal could make the wearer invisible. The ancient Australian aborigines, however, envisaged a more sinister origin. They thought opal to be half serpent and half devil, and that the brightly coloured fire within was an attempt to lure them into the devil's lair.

Pliny the Elder marvelled that this kaleidoscopic gem encompassed in its gentle frame the fire of the ruby, the brilliant purple of the amethyst, the sea-green of the emerald, all shining together in an incredible union. He frequently waxed lyrical about opal, saying it was made up of the glories of the most precious gems, and to describe it was a matter of inexpressible difficulty. He went on to compare it with a painter’s palette or of a fire quickened by oil.  Other writers have compared opals to volcanoes, galaxies, and fireworks. Admirers gave extraordinary opals poetic names such as Pandora, Light of the World, and Empress. In ancient Rome, this gem symbolised love and hope.

Ancient Romans also provided the first real market for opal. With a rich powerful empire, wealthy citizens for the first time acquired disposable income and with this came a passion for gems. Opal, whose colours changed with every shift of light, was rarer than pearls and diamonds and destined to be the stuff of myths and dreams. Mark Antony was said to love opal. Indeed, legend has it that he so coveted an opal owned by a Roman Senator that he banished him for refusing to sell the almond sized stone, reputed to be worth 2,000,000 sesterces. ($80,000). It is believed Mark Antony coveted the opal for his mistress, Cleopatra.  There is a story that one Roman Emperor even offered to trade one-third of his vast kingdom for a single Opal.

Opals were set in the Crown jewels of France and Napoleon presented to his Empress Josephine a magnificent red opal called ‘The Burning of Troy’ which contained brilliant red flashes.

In the Middle Ages, opal was considered a stone that could provide great luck because it was believed to possess all the virtues of each gemstone whose colour was represented within it.  Healing qualities of opal are said to include increasing energy levels, balancing and soothing of emotions and the bringing of clarity of mind – very useful with today’s hectic pace of life! It was also said to confer the power of invisibility if wrapped in a fresh bay leaf and held in the hand. Regrettably, this wonderful reputation was somewhat tarnished when, in his novel Anne of Geierstein, novelist Sir Walter Scott turned it into a talisman with supernatural powers. Following publication, opal sales dropped within a year by 50%, and remained low for some time.  As recently as the beginning of the 1900s Russians still believed opals embodied the evil eye.  Happily for us, both Scott and the Soviets have proved false prophets and opal is again revered for its beauty and ever changing colours.  After falling so badly out of favour in the late 18th and early 19th centuries, Queen Victoria did much to reverse its unfounded bad press. She became a lover of opal, kept a fine personal collection, wearing opals throughout her reign. Princess Mary, Duchess of Gloucester, gave an opal ring to her niece Queen Victoria in 1849. This opal ring had previously been in the ownership of Queen Charlotte since about 1810. Queen Victoria's friends and her five daughters were presented with fine opals and the stones became highly sought after because the Royal Court of Britain was regarded as the model for fashion worldwide.

Opals have been found in varying forms. One such, fire opal (mainly from Mexico and Oregon), is a transparent to translucent specimen, with warm body colours of yellow, orange or red. These opals do not usually show any play of colour.  Fire opals are sometimes referred to as jelly opals.

Peruvian opal (also called blue or pink opal) is a semi-opaque to opaque stone, which, in the more opaque stones, is often cut to include its matrix (hast medium).  It does not display play of colour. 

Although it has been reported that Northern African opal was used to make tools as early as 4000 BC, the first published report of gem opal from Ethiopia appeared in 1994, with the discovery of precious opal in Ethiopia.  In 2008, deposits were found in Wollo Province.  Now more commonly referred to as ‘Welo’ or ‘Wello’, this opal has become the dominant Ethiopian opal in the gem trade.

However, the most famous location for opals of outstanding beauty and quality is the town of Coober Pedy in South Australia and indeed opal is the country’s national gemstone. The world's largest and most valuable gem opal ‘Olympic Australis’ was found here in August 1956 at the ‘Eight Mile’ opal field.  It weighs 17,000 carats (7.5 lb) and is 11 inches long, with a height of 43⁄4in and a width of 41⁄2 in! Coober Pedy is also home to the best and most valuable examples of black opal.

Opal is considered the birthstone for people born in October but fortunately for us the old wives’ tale that it is unlucky if worn by those not born in that month has been rightly discredited, allowing everyone to revel in the luxury of ownership of this most amazing gemstone.

Finally, in late 2008, NASA announced it had discovered opal deposits on Mars… now we know why there are so many space expeditions scheduled to visit that planet!


Keep an eye out for Kristaval’s Opal pieces as you scroll through our pages…

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