I recently heard that one could distinguish real “rock crystal” beads
made of quartz from those made from leaded glass or other glass
materials frequently described as “rock crystal” by looking at the
hole piercing them. If you can see the thread or other material the
beads are strung on when looking through a bead, then its glass. All
my quartz beads pass this test, as one cannot see the thread, but
only the hole drilled through the bead. From the outside, it just
looks like a thick white line with slightly fuzzy looking edges.
Of course, if you examine the beads with a loupe, you are likely to
see many little imperfections that may be dark lines (like rutilated
quartz) or just dark specs in quartz, while tiny bubbles can sometimes
be detected in glass.
I’ve heard about another test, which consists of examining the point
on the bead where the hole is drilled. If the bead is faceted, the
plane through which the hole passes should be polished flat. All the
edges of the facets should be sharp and definite. I don’t think that
this holds true, as some Austrian crystal (which are glass with, I
think, a high lead content like the old-fashioned cut glass) passes
I hope this is the kind of you wanted. I’m posting it
rather than sending it off-list because I’d like to know if more
knowledgeable orchidists can add info.