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Meta-chert Pendant
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Posted by: frank Post Reply
12/27/2018, 19:22:32

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.

ChertBeadDec18Web.jpg (114.8 KB)  ChertBead2Dec2018Web.jpg (179.3 KB)  


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Wow, Frank, thanks for taking the time to provide such interesting mineralogical info!
Re: Meta-chert Pendant -- frank Post Reply Edit Forum Where am I?
Posted by: beadiste Post Reply
12/27/2018, 19:49:49



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Re: Wow, Frank, thanks for taking the time to provide such interesting mineralogical info!
Re: Wow, Frank, thanks for taking the time to provide such interesting mineralogical info! -- beadiste Post Reply Edit Forum Where am I?
Posted by: frank Post Reply
12/27/2018, 20:46:31

I am fascinated by the attempts of bead researchers to use chemical analysis of glass beads to determine the type of constituents the bead was created from to try to pinpoint where the glass and bead may have been manufactured. Trade routes as described by anthropologists are to me analogous to geologists descriptions of the long slow journey this rock made from the area off the southern coast of Mexico to the mountains of western Washington. Both of these efforts require us to have a belief in a process of inquiry that is not exact yet compelling.



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