Its history goes beyond that of Man and extends throughout our planet. From the Sanskrit ‘Upala’ meaning precious stone, the Latin ‘Opalus’, and the Greek ‘Opallios’, its name means ‘of changing colour’
Exploited for 10,000 years in the Virgin Valley in North America, objects decorated with Ethiopian opal were discovered in a cave in Kenya and dated to 4,000 BC.
Legends related to meteorological phenomena were attributed to it among various cultures: the Aborigines called it the ‘snake of the rainbow’ as the god creator was considered to have united the colour spectrum to create this stone. This concept is found in India, where the rainbow goddess transformed into an opal to escape the many suitors captivated by her beauty. Arab culture asserts that lightning bolts trapped in rock created opal.
In ancient Greece, it came into being through the eyes of King of the gods Zeus: his tears of joy following the triumph against the Titans turned into opal on contact with the ground. Since then, Greeks attributed it powers of foresight and prophecy, a belief found in the Middle Ages, when it was renamed ‘ophthalmios’ (eye stone), in reference to its virtues of vision.
To Romans, it was a sign of hope and purity. They were the first to commercialism it, peaking interest: Marc Antoine is said to have banned a senator for refusing to sell him an opal destined for Cleopatra estimated today at 60,000 euros.
Some of the most famous and valuable in the world include:
Opal is formed through alternating dry and wet periods. Precipitation, via the erosion phenomenon, transports various elements into groundwater, including silica, a natural form of silicon dioxide that accounts for more than 60% of the mass of continental crust. Through an aqueous chemical reaction called hydrolysis, silica forms opal which is rich in impurities. Once a new dry period begins, the upper layers of chalcedony and quartz, from which opal is extracted, form as a result of evaporation. This volatile and at times miniscule silica deposit requires delicate hand mining. The primary deposits have been noted on the Pacific and American continents, but also in various other parts of the world.
It was discovered in Australia in 1849 lodged in layers of sandy clay deposited by the sea throughout the Cretaceous period and during the creation of the Great Artesian Basin. Opal production then began in 1890 in the region that became New South Wales and Queensland. Today, 75% of opals come from the fields of Coober Pedy: discovered in the 1920s, they span 70 kilometres.
Considered a mineral until 2007, opal stone is composed of several elements: cristobalite, tridymite, hydrated amorphous silica, and water content which varies according to the variety. It cannot therefore be considered a mineral. It is distinguished from quartz due to its crystalline structure. Its quality is determined by the purity of its crystals, creating iridescent reflections.
The colour play comes from its light diffraction resulting from the random arrangement of microscopic plates of tridymite spheres, or cristobalite. This feature distinguishes the two primary opal varieties:
‘Harlequin’ opal is characterised by an extremely rare distribution of colours similar to the tile of the same name, though its background colour can be black, white, or boulder. However, is not a recognised variety.
These varieties are distinguished by origin, background colour or the nature of the gem:
Litho therapy uses crystals to work with energies and the chakras.
Opal’s water content dissipates energy blockages related to beliefs, and fears of loss, whilst restoring the flow of energy. It helps to awaken the consciousness, allowing you to let go and live in the present.
Each variety has its own vibration and effects for different purposes:
In addition, the choice of colour should not be overlooked:
Opal stone works both psychologically and physically, the two being intimately linked. It purifies the blood and kidneys, facilitates childbirth, and alleviates premenstrual syndrome. A sensual stone with aphrodisiac effects, it heightens the senses and removes inhibitions.