Thread: found object
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Old 10-17-2012, 03:27 PM
Andrew Werby Andrew Werby is offline
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Join Date: Dec 2005
Location: Oakland, CA
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Re: found object

It could be a piece of fossil shell replaced by micro-crystalline quartz (chalcedony). But quartz (silicon dioxide) isn't as hard as many gemstones that are commonly cut with diamond. It has a Mohs scale hardness of 7, the same as popular semi-precious stones like agate or jasper (both forms of micro-crystalline quartz).

Note that the Mohs scale of hardness isn't a linear scale; the difference between a 7 (quartz) and 8 (topaz) is not as much as between 8 and 9 (corundum), which itself is much softer than diamond. Here's a chart that shows both Mohs scale hardness and true hardness:

Andrew Werby
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