Item Information

Dimensions (mm) not provided
Weight (carats) not provided


This is  a natural untreated agate from Usa well polished and ready for setting.

Weight 14.20 cts app

size 19 x 18 x 5 mm app

Montana Moss Agate, a name given to the beautiful chalcedony found, most abundantly, in the alluvial gravels of the Yellowstone River, would probably be better named Yellowstone Agate, because its genesis was centered in the Yellowstone Park area. The actual tremendous volcanic activity that produced the conditions necessary for the formation of agate, spanned hundreds of miles and millions of years.


"Eastern Montana was mostly a shallow inland ocean, almost a swamp with huge forests lining its shores and islands of volcanoes spewing forth lava to entomb parts of the forest in lava and ash.  The bowels of Yellowstone bulged and roared and flowed mountains of lava that decimated thousands of acres of mighty redwoods and sequoias for hundreds of miles.  This decimation continued for hundreds of years with layer upon layer of forests growing up and being driven down under the ponderous weight of all the megatons of lava and ash. The hot lava devoured most of the wood in its rush to cover the trees, but some of the shape and ingredients of the limbs remained trapped in the cooling lava.  When the time of the volcanoes and lava was subdued and the rains came, mineral laden silica-water flowed into the cavities and pockets left by the dying trees and bubbling lava.  As flow after flow slowly filled the pockets with liquefied silica, Montana Moss Agate was born."

7h 20m 54s

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Pricing & Details

Bid Increment $1.00
Starting Bid $11.00
Auction ID 213683
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Viewed 378 times
Starts 14th Oct 2016 8:02pm PDT
Ends 20th Oct 2016 8:00pm PDT

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