wrote in message
...
On Feb 26, 3:56 pm, "Ed Huntress"


'Can't help there, Kevin. Quartz is, of course, chemically identical to
glass, but is crystalline. And practically all glasses contain
impurities.

--
Ed Huntress

Actually quartz can be either crystalline or amorphous.

Dan

Clear, pink, and other colors, too. g

--
Ed Huntress