Posted by: frank Post Reply
Meta - chert pendant from Washington. The huge array of meta - cherts from Washington have one commonality , they are difficult to work because they have a much lower silica content than jaspers and agates. The siliceous meta - cherts have a range of silica content from 89% to 92 % while agates and jaspers that we see in the trade are 99 % silica and are very easy to work. These meta - cherts have been closely studied by geologists and it is known that they form where the Pacific plate meets subsidiary plates causing spreading centers , places where magma surfaces and widens the earth's crust. Associated with these spreading centers are black smokers which are mineral laden jets of hot water bringing iron and manganese up to the ocean bottom where it precipitates out of solution and mixes with silica that is of biological origin .The silica is the remainder of diatom shells falling our of the water column minus the carbonate content which goes into solution at these depths. A couple of metamorphisms and you have meta- chert. The pink is a conglomeration of tiny maganese garnets , spessartite garnets. It actually works like glass.47 mm long , 6 mm hole.
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