Was browsing gems on eBay and came across slabs of this crazy
stone. The listing says it is new and there is controversy over
whether it is man made or not. It is layers of every color of the
rainbow and looks man made, but no one has been able to prove it.
Can anyone out there shed some light on this stuff?
Jill, before the NAFTA agreement, Rainbow Cal Silica was more often
called Detroitite. As in Detroit, Michigan. You know, where
automobiles are manufactured and painted. One seller on eBay cites
testing by GIA resulting in the identification of man-made pigments
and polymers. People around the world differ in their opinions of
GIA's educational programs (I certainly don't, I'm a GIA GG and an
alumnus), but few dispute their Gem Trade Laboratory's abilities.
I have a smallish chunk (as opposed to the thin slabs you see on
eBay) of the early "Detroitite" which is most obviously comprised of
layer upon layer of........paint. Automotive paint. Don't get me
wrong either, I'm not saying that just because it is paint doesn't
mean it isn't attractive or a jewelry possibility. One of the most
beautiful pieces I've ever seen was a cabochon of Rainbow Cal Silica
which was cut oriented parallel to the layers (with a sort of
rainbow wood grain look) and prong set on a flat piece of Mokume
Gane. Gorgeous! One of the funniest things I saw was a large quartz
crystal with several gemstones attached to it with wire. One was a
piece of this material that was shaped like a Zuni bear. It was made
by a Southwest Indian and was purported to have some kind of
Anyone interested in viewing the chunk I have can contact me
off-list with this thread title in the subject line. If I get a
response, I'll snap a photo and send it to you. If you've only seen
slices of this material, the photo of my chunk will illustrate for
you the true nature of this "gemstone."
James in SoFl