From: geoffrey cunnar <@yale.edu>
Date: Thu Dec 11, 2003  6:54:48  AM US/Pacific
To: jgood@importfood.com
Subject: Re: hardness/specific gravity of granite

Hi Jerry,
I am pleased to report that the mortar and pestle have proven
themselves to be capable of crushing quartz rock.  I estimate that i
have pulverized somewhere around 10 pounds of quartz for my
experiments here at Yale.  Quartz, as you might know, has a Moh's
hardness of 7 (scale of 1-10).  The pestle has been beat up a bit at
the end but that is to be expected for such a hard mineral.  I have
been told that i should try first heating up the quartz as this will
reduce the amount of force it takes to pulverize the rock.  I have yet
to try this.  In short, your company's granite mortar and pestle are
pretty darn tough and versatile.  I still have quite a bit more quartz
to pulverize for my current research and will keep you posted.

Thank you for the follow up,

Geoffrey Cunnar 
(Yale University graduate student who is studying stone tools from the Liangchengzhen excavations in China)