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  #1  
Old 10-15-2012, 07:14 AM
yserbey yserbey is offline
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Join Date: Nov 2008
Location: beyrouth-lebanon
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found object

while walking on the beach i found this stone, i a weird way, it look like clitoris. took to home, try to make a hole to display it on a proper socle, but it was impossible to do it, i take it to a friend wiz diamond tool, again it was impossible to make a hole ! what do u think this stone is?
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  #2  
Old 10-15-2012, 04:35 PM
Andrew Werby Andrew Werby is offline
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Location: Oakland, CA
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Re: found object

Since it's obviously not a diamond, a diamond tool will cut it. But you probably weren't using the right tool to deal with it effectively. Most diamond tools should be used wet, so either pour water on it when cutting (use a GFI breaker to avoid shock hazard) or make a little dam around the place you want to make a hole and fill that with water. For large holes in stone (bigger than a few mm), a diamond core bit is used and the core broken away. It also helps to use some kind of drill press with these bits.

Andrew Werby
www.computersculpture.com
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  #3  
Old 10-16-2012, 01:40 AM
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Dries Dries is offline
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Re: found object

It looks to me like a silicified shell (fossil) and the reason it’s so hard is because of all the silica.
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  #4  
Old 10-16-2012, 09:27 AM
yserbey yserbey is offline
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Re: found object

i even put it on a lathe, nothing happend , just smoke!
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  #5  
Old 10-17-2012, 04:27 PM
Andrew Werby Andrew Werby is offline
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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: http://www.allaboutgemstones.com/moh...ess_scale.html

Andrew Werby
www.computersculpture.com
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  #6  
Old 10-18-2012, 07:39 AM
yserbey yserbey is offline
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Re: found object

many tanx for ur care.
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