Large Rough Opal - SOLD 1.08"







Large Rough Opal - SOLD 1.08"




























Above: Front of the Specimen Card
A gemstone almost alive with an intense inner fire, opals have held the attention of humans for many thousands of years. From Egypt and Classical Greece to China and the Americas, ancient civilizations valued the beauty of opal, but it is only in recent history that we've come to understand the complex nature of this unique gemstone.
This specimen is a 1.08" piece of rough opalized plant material is opalized fossil plant material from Lightning Ridge in NSW, Australia. It is quite a bit larger than our normal specimens and has a beautiful shine to it.
Australia is the largest producer of opals in the world. The opal fields here date to the Cretaceous when Central Australia was home to an enormous inland sea, known to science as the Eromanga Basin. It dates to roughly 110,000,000 years old.

A Dazzling Gemstone
This specimen is a fragment of rough opalized plant material is opalized fossil plant material from Lightning Ridge in NSW, Australia. Australia is the largest producer of opals in the world. The opal fields here date to the Cretaceous when Central Australia was home to an enormous inland sea, known to science as the Eromanga Basin. It dates to roughly 110,000,000 years old.
It is a uniquely large opal, measuring 1.08" — the largest rough opal in our collection. This is a one-of-a-kind item with a beautiful multicolor look.
You can see our full collections of smaller opals here.

"Opals combine brilliant qualities of the most valuable gems and, above all, defy description." ~ Pliny the Elder
MORE ABOUT OPALS

DIFFRACTING LIGHT
Unlike most gemstones, opal does not have a single crystalline lattice structure stretching throughout the material. Rather, opal is a collection of very tiny spheres of silicon-dioxide which are packed together and compressed. Scientists estimate it takes up to five million years to form a single centimeter of natural opal.
The "fire" of opal is the result of diffraction as light passes through the silicon-dioxide sphere within the stone.
As illustrated here, the spheres are aligned in an ordered network that diffracts continually the white light as it passes through each sphere and creates the shifting, brilliant colors we see.

📸 Macro image of an exceptional (and large) rough opal specimen.
Formed in the Earth
Opal forms in areas where water comes in contact with sandstone and filters deep into the Earth, picking up more silica along the way. This silica-rich solution settles into cracks, natural fractures in the rock, or even into fossilized organic material. Under the intense heat and pressure, most of the water evaporates leaving the silica behind.
As noted above, this particular specimen is opalized fossil plant material from Lightning Ridge in NSW, Australia. Australia is the largest producer of opal in the world. The opal fields here date to the Cretaceous when Central Australia was home to an enormous inland sea, known to science as the Eromanga Basin (or Sea).

The Eromanga Basin in Central Australia was home to a great inland sea for about 95 million years during the Mesozoic Era. This sea was home to many forms of marine life including Plesiosaurs, Ichthyosaurs, and Ammonites. The deposits in Lightning Ridge date to roughly 110,000,000 years old.

Front of the Specimen Card

Back of the Specimen Card
Further Reading
Eckert, Allan W. The World of Opals. John Wiley & Sons, 1997.
Leechman, Frank. The Opal Book.


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