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Precious opal (Spencer Opal Mine, Spencer, Idaho, USA). Photo:James St. John |
Geyser Opal from Spencer Idaho U.S.A Spenser Opal was deposited in volcanic rocks about 4 million years ago by geysers.
The primary formation of the mine is a rhyolite and obsidian flow full of gas pockets. The Opal Solution or silica, was a secondary deposit carried by geyser activity. As a result of several eruptions over a period of time, the opal lays in layers. Most of the layers are thin, resulting in some of the most beautiful triplet opal in the world. Occasionally the layer will be thick enough for cutting a solid opal which is an extra bonus for the finder.
Opal doublets, often used in jewelry, are thin slices of precious opal glued onto a matrix material. Such gems are considerably cheaper than solid opals, yet provide the same play of color. Opal doublets are sometimes coated with a thin layer or dome of clear Quartz to make them more resistant to scratches (opal is a relatively soft gem). These are known as triplets.
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Precious opal (Spencer Opal Mine, Spencer, Idaho, USA) |
Where You can find it?
Spencer Opal Mine, Spencer, Idaho The opals are contained in a rhyolite and obsidian flow with abundant gas pockets. Hydrothermal fluids from hot spring activity filled the pockets with common and precious opal. The cost for digging is $15.00 for adults (13 and up) $10.00 for kids (4-12).
Address: 27 Opal Ave, Spencer, ID 83446
See also:
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Part II: Top Spots For Gem Hunting In The US
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