ATM Lenses from natural quartz

[Dominic-Luc Webb molmed <Dominic.Luc-Webb@molmed.ki.se>]

I was just thinking that I have never actually seen
it specifically stated that naturally occuring clear
quartz was used to make quartz optics. I often take
for granted that many such materials are made
artificially in a kiln, etc, but exist in the wild.
Does anyone here know (maybe a reference) that naturally
occuring quartz can be used to make optics and any ideas as to
how suitable it is in making high quality lenses (i.e., UV
transmitting, etc)?

Dominic