Re: ATM Marble Tool for Plate mirror?

[Anthony Stillman <atmer@flash.net>]

>...Is the marble's hardness comparable to plate glass

>...would marble work as a mirror

Vero,

Though most marble is harder and tougher than soda-lime glass, it should
work fine as a tool.  You will probably find when changing radius that you
loose a bit more thickness in the glass as a result, but I don't think this
will be a problem.

Regarding a marble mirror, it seems a shame to coat a nice piece of marble
with aluminium.  Also, like many non-manmade rocks marble is inhomogenious.
I suspect it could be made to work and I also suspect it would be tricky to
obtain a smooth figure.  Further, pulling a good vacume on it might take a
while.  Still, it is intriguing. (read, thanks a lot for getting me
started, like I have the time ;-) ) I onece made a polished elliptical
granite convex for the base of a menorah.  After roughing it in with a
water cooled silicon-carbide grinding wheel I finished it with standard
mirror making techniques.  I stuck polishing pads on the tile/plaster tool
to polish.  If was very pretty and it was far too porous to function as a
mirror.

Anthony