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Opal Properties, Meaning, Facts and Photos

precious opal gemstone with play of colour
Contents

1. What is Opal?
2. What is Common Opal?
3. What is Boulder Opal?
4. Meaning of Opal
5. Are Opals Bad Luck?
6. Opal Healing Properties
7. Article Pictures
8. Shop Common Opal

What is Opal?

Opal is a form of silica with a high water content.

Under the right geological conditions, as certain rocks break down silica is released into groundwater trapped in cracks and voids.  Over long periods of time as the silica dissolves the mineral-rich water dries into a gel.

The silica in opal forms closely packed spheres of a similar size that come together in a regular repeating arrangement.  The spaces between the spheres contains water.  Light diffracts off the spheres as it passes through the stone which produces a rainbow of colours.

Diffraction is the bending of light as it goes around an object.  Refraction is the bending of light as it enters an object.
    
Diffraction only happens when the minute silica spheres share a similar shape and size.  They must also be arranged in a neatly arranged pattern.

The quality of the iridescence (also known as 'play of colour') that can be seen in opal is dependant on the size of the spheres and the space between them.  The more uniform the shape and size the brighter and more intense the colour.

The most common colours seen in opal are red, orange, green and blue.  

As 'precious opal' is gently moved around, depending on the size of the spheres light reflects from different angles.  With smaller spheres blue and violet can be seen whilst larger spheres produce reds and orange.

Despite being called 'precious opal' this material is not classed as a precious stone.rough precious opal

What is Common Opal?

Common opal has the same chemical composition as precious opal.  The main difference between the two is common opal does not exhibit 'play of colour'.

The reason for this is because the arrangement of the silica spheres is more random.  With common opal having a different structure it doesn't diffract light.

Common opal is also known as 'potch'.

Although the vast majority of the world's opals are common opal it's not as well known as precious opal.

This variety is called 'common' opal because it's fairly common and can be found in many countries around the world.

When used for gemstones both precious and common opal are polished as cabochons.

Pink opal from Western Australia is pink mookaite.  It's mined close to Mooka Creek where the variety of jasper called 'mookaite' is found.

What is Boulder Opal?

Boulder opal forms in thin veins within ironstone boulders.  This host rock is called ironstone.

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.  The brown external appearance is due to the oxidation of the stone's surface.

Ironstone can also be found in a red and black banded form.  When polished as a gemstone this material is also known as tiger iron.Opal does not have a crystalline structure. It's therefore classed as a mineraloid or an amorphous solid.

To be described as a mineral a naturally occurring solid must have a crystalline structure.

Precious opal stones are fragile so need to be looked after carefully.  If exposed to heat they can lose moisture and dry out which causes crazing.  This term refers to a network of very fine cracks.

Around 95% of the world's opal comes from the outback deserts of Australia.  The remaining 5% comes from Mexico, Brazil and the U.S states of Idaho and Nevada.

More recently opal has been found in Ethiopia and Mali.

Opals were discovered by Australian gold prospectors in 1863.  They're believed however to have been mined much earlier by the Aztecs in South and Central America.

Some reports state opals from Ethiopia were being used as tools as early as 4000 BC.  Factual evidence to support this is fairly vague.

The Meaning of Opal

The meaning of 'opal' may have come from the Sanskrit word 'upala' meaning 'valuable stone'.  Upala is likely to have come from the Greek 'opallios' which loosely means 'a gem with a kind of play of colour'.

Legends and myths have been associated with rocks and minerals for thousands of years.  A story once told by Australian aborigines claims God came down to earth on a rainbow to bring the message of peace to all mankind.  At the spot where his foot touched the ground the opal came alive and sparkled with the colours of the rainbow.

The ancient Greeks believed opal could give the wearer the power of foresight.  The Romans revered it as a symbol of hope and purity and believed it could offer protection from disease.

Eastern cultures regarded opal as a symbol of truth whilst ancient Arabs believed it came from heaven.  They also believed it acquired the play of colour from flashes of lightning.

During the Middle Ages opal was thought to be beneficial for eyesight.  Some claimed it could render the wearer invisible.  For this reason stones were often carried by thieves.

The French Emperor Napoleon gave his wife Josephine a magnificent opal called 'The Burning of Troy'.  The name came about because of the stone's variation of colour.

opal embedded in petrified wood

Are Opals Bad Luck?

Opals have long had a reputation for being bad luck.  This superstition came about because of a book written by Scottish historian, novelist, poet and playwright Sir Walter Scott.  Published in 1829, 'Ann of Geierstein' describes opal as being an unlucky stone.

Its reputation was gradually restored by public figures including Queen Victoria and French actress Sarah Bernhardt.

Opal is also thought of by some as being unlucky because it can crack or become damaged very easily.  When replaced, subsequent stones may also crack.  This contributes to the perception that opal is unlucky.

The real reason for the stone cracking is likely to be because of dehydration. 

Opal Healing Properties

Opal is considered to be a stone of true love.  It enhances positive characteristics for those born under the zodiac sign of cancer.  It's the modern and ayurvedic birthstone for the month of October.

A delicate stone that enhances psychic and mystical visions, opal stimulates originality and boosts creativity.

Opal is a stone of reflection that picks up on positive feelings and memories and amplifies them. 

Being associated with love, passion and desire it stabilises emotions and gives the confidence to explore intimate feelings.

It encourages a positive attitude and brings loyalty, respect and understanding.

Opal has a calming and soothing effect on emotions and can help manage stress, anxiety and feelings of being overwhelmed. 

It brings emotional balance and enhances the ability to express feelings clearly and with conviction.

When used for meditation opal creates a deeper connection to the spiritual realm.  Its aligns with the third eye chakra.

Opal enhances creativity and inspiration.  It stimulates the imagination and enhances artistic expression.  It can be used as a talisman to help artists and writers overcome creative blocks and find new sources of inspiration.

In love and relationships opal is a symbol of trust and commitment.  It strengthens friendships and encourages loyalty and faithfulness in a romantic relationship.

It can be used to ease the healing process from the trauma of a past relationship.

When being worn or carried opal helps you become more attuned with the energy of the surrounding environment.  This allows you to blend in seamlessly with a crowd and become less conspicuous.

Article Pictures

The opal in the photo at the top of our article is from Andamooka in Southern Australia.  The second photo is courtesy of James St. John.

The last photo is opal in petrified wood.

The opals in photo 1 and 3 are housed in the Natural History Museum Los Angeles.  Both images are courtesy of Stan Celestian.

Photos are clickable and redirect to the original images.

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