Opal Stone Facts and Photos
1. An Introduction to Opal
2. Origins Properties and Meaning of Opal
3. More Interesting Facts
4. Article Photos
5. Our Collection of Pink Opal
6. Read More
An Introduction to Opal
Along with the mineral tourmaline opal is the birthstone for the month of October. Stones are either classed as precious opal or common opal. The precious variety boasts an iridescence known as "play of colour" and these stones have been highly prized since Roman times. Common opal which from a geological perspective is almost identical lacks play of colour, is usually opaque and can be found in many different colours. Play of colour is caused by the reflection and scattering of light from the minute uniformly sized and closely packed silica spheres within opal. The silica spheres formed when groundwater rich in minerals seeped into deep cracks and voids within the Earth's crust and subsequently dried up.
Around ninety five per cent of the world's opals come from the outback deserts of Australia and the remaining five per cent are mined in Mexico, Brazil, the U.S states of Idaho and Nevada and more recently reserves have also been found in Ethiopia and Mali.
Although first discovered by Australian gold prospectors in 1863, opal is believed to have been mined much earlier by the Aztecs in South and Central America. There are reports which state that opals from Ethiopia were being used as tools as early as 4000 BC although evidence to support this is fairly vague.
Origins Properties and Meaning of Opal
Legends and myths have always been associated with gemstones and a story told by Australian aborigines claim God came down to earth on a rainbow to bring the message of peace to all mankind and at the spot where his foot touched the ground, opals came alive and sparkled with all the colours of the rainbow.
The origins of the name opal possibly came from the Sanskrit word 'upala' meaning 'valuable stone' which in turn may have come from the root for the Greek term 'opallios' meaning 'colour change'. The Ancient Greeks believed opals could give the wearer the power of foresight whilst the Romans revered them as a symbol of hope and purity and believed they could offer protection from disease. Eastern cultures regarded them as being a symbol of truth and ancient Arabs believed the stone came from heaven and acquired its play of colour from flashes of lightning. During the Middle Ages it was thought to be beneficial for eyesight and some even believed it could render the wearer invisible hence opals were often carried by thieves. The French Emperor Napoleon gave his wife Josephine a magnificent stone called 'The Burning of Troy' named because of the variation of colour.
Today in crystal healing opal is said to help those who wear the stone to find true love. It can enhance the positive characteristics for those born under the zodiac sign of cancer and is the modern and ayurvedic birthstone for the month of October. It's also the mystical birthstone for April.
A superstition brought about by the novel Ann of Geierstein written in 1829 by Walter Scott damaged the opal's popularity because it was described as being an unlucky stone but its reputation was gradually restored by public figures such as Queen Victoria and French actress Sarah Bernhardt.
More Interesting Facts
Common opal which is not as well known or as popular as precious opal can be found in many different colours but the most highly sought after are pink and green. Stone are almost always opaque and the reason it's called "common" opal is because it can be found in many countries around the world. Like the precious variety it's always shaped as a cabochon.
Boulder opal forms in thin veins within ironstone boulders. The main constituents of these fine grained heavy and compact sedimentary rocks are oxides of iron, clay and/or sand. Freshly broken ironstone is usually grey however the brown external appearance is due to the oxidation of its surface. Ironstone can also be found in a red and black banded form and when the mineral is polished as a gemstone it's better known as tiger iron.
Opal does not exhibit a crystalline structure therefore cannot be described as a mineral and is instead correctly known as a mineraloid or an amorphous (non crystalline) solid.
Precious opals are fragile and need to be well looked after. On Mohs scale of mineral hardness they grade 5½ to 6½ so should be protected whenever not being worn.
The opal at the top of this page is which is from Andamooka in Southern Australia is on display in the Natural History Museum Los Angeles. The second photo of opal in petrified wood is in the same museum. Both photos are clickable and redirect to the original image. Photos courtesy of Stan Celestian.
Our Collection of Pink Opal