The History of Opal
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The History of Opal The History of Opal
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The History of Opal. Throughout the centuries opal has been prized and found in many countries. But it is in the Australian desert that the most breathtaking of gems are found. 120 million years ago much of Australia was covered by a great inland sea. - PowerPoint PPT Presentation
Transcript of The History of Opal
The History of OpalThe History of Opal
• Throughout the centuries opal has been prized and found in many countries
• But it is in the Australian desert that the most breathtaking of gems are found.
• 120 million years ago much of Australia was covered by a great inland sea.
• Below that was mineral rich sand containing silica. • As the ocean receded over time, under pressure the sand
turned into rock.
• For thousands of years storms raged and the rain slowly dissolved the silica out of the rock.
• With the water the silica moved deep underground until it could settle in fissures and cracks.
After tens of thousands of years the water evaporatedleaving the silica to combine and form into opal.Minute droplets of water were trapped in the opal and refractlight to give off an hypnotic array of colors. Opal was born!
• Opal was first found in Angaston, South Australia in 1849. Queensland attracted miners in the 1880’s and formal production began in White Cliffs(NSW) in 1890, and Opaltown(QLD) and Lightning Ridge(NSW) in 1900.
• Then came the richest opal fields in the world, all in South Australia - Coober Pedy in 1912, Andamooka in 1930 and Mintabie.
• After World War I many soldiers returned to Australia and sought their fortune and solitude in the opal fields. As there were no building materials and they were used to the trenches they simply “dug in.”
• The Aboriginals in the area were amused by this activity and coined the phrase “Coober Pedy,” which means White Man’s Burrows.
• Initially mining was done with a pick but the introduction of explosives made tunnelling and moving larger amounts of rock easier. Even now, some miners prefer to work this way.
• Originally the rock had to be bagged and raised to the surface, first by hand and later by a powered winch.
• Today a digging machine which incorporates a large vacuum, sucks up all the rock and dumps it into a pile on the surface for further inspection.
• Other forms of mining have evolved such as “open cut,” in an effort to find this elusive gem.
• “It is very hard to find something you never lost.”
