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Gem Identification


#1

As I was reading everyones post on this subject I thought I would
bring in a personal experience I recently had.

I first want to emphasize that gem books are wonderful and there is
a great deal to learn, however there are books that do contradict
each other. (well known and respected books). It then comes down
to having a gemstone papered from a reputable lab especially for an
expensive stone.

The material that I am writing about is Cat’s Eye Actinolite from
Russia. This material is a spinach green with some of it having a
very strong and beautiful cat’s eye. The question came as to
whether this material is Cat’s Eye Nephrite Jade. In reading my gem
books and going to the library and doing hours of research I found
some differing opinions. There has been material from Alaska that
had been recorded (I believe in the early 1950’s) that there existed
Cat’s Eye Nephrite. There is reference to this in the Standard
Catalogue of Gems by Anna Miller and John Sinkankos. The book
published from the GIA in 1957 does not reference any cat’s eye
Nephrite, however in there more recent editions they state that any
Nephrite with a cat’s eye is properly called Cat’s Eye Actinolite
because of its structure. The gembook by Webster Fifth Edition of
Gems Their Sources, Descriptions and Identification indicates that
it is a judgement call. I also have 6 other references that
indicate there is a material called Cat’s Eye Nephrite.

This is expensive material so I had sent it to a very reputable
Laboratory and asked for papers on it. As of now it has been
papered as Cat’s eye Actinolite however there is supposed to be some
more extensive testing done. I must sell the material as Cat’s Eye
Actinolite.

In the meantime we have been trying to take a picture of some of
these stones. The material is extrememly reflective and when
putting inside a “light box” the reflection disappears and so does
the cat’s eye. When taking a picture of it outside of the light box
we can get a weak cat’s eye however the rest of the room is
reflected in the stone. We have just upgraded our camera to a Nikon
995 however the camera is at Nikon (white balance problem). I am
hoping that when the camera comes back that we will be able to take
a proper picture of this material so I can put it up on my website.
If anyone is interested in seeing the material let me know and I
will inform you when the material is up on the website.

Diane Sadel
http://www.sweegemstones.com


#2

Diane, Wow, you bring up a real question here. In the 1970’s while
living on Taiwan, the big stone at the time was Taiwan Nepherite. It
was plentiful and cheap and the factories were chuggin it out by the
ton. I still have about 15 lbs of good stuff I dug out of their slag
piles!.

The point is, every now and then some cat’s eye material would
surface. Purchased several and still have them (just don’t want to
part with them). I also have a piece or two of the nepherite that
came from the Taiwan mines that I believe will cut eyes. The
question is, is all the material from Taiwan nepherite or is some of
it actinolite? Guess I will dig up both the cut and uncut stones and
decide what to do with them.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! dcdiet@mediaone.net


#3

Hi Don

The question is, is all the material from Taiwan nepherite or is
some of it actinolite?  Guess I will dig up both the cut and uncut
stones and decide what to do with them. 

Nephrite is an Amphibole. It is made up of Tremolite and Actinolite
and when it forms as compact fibres it is called Nephrite Jade. It
is a calcium-magnesium-(iron) hydroxyl silicate. When free of iron
it is light in color or white (tremolite). When iron replaces the
magnesium green results (actinolite). It results from the
metamorphism of impure limestones or dolomites. Also in green
schists and gniesses (actinolite).

It is also found along the Kobuk River, Alaska; in the gravels of
the Frazer River, B.C., Canada; Wyoming; Khotan, Turkestan; New
Zealand.

You can check Minerology by Sinkankas, Peterson’s Field Guide to
Rocks and Minerals, and Audobon Society Field Guide to North
American Rocks and Minerals. Here is also an online link to minerals
http://www.geology.wisc.edu/~jill/glossary2.html and
http://webmineral.com/AtoZ/IndexJ.shtml.

I hope this helps explain Nephrite better. Karen Seidel-Bahr the
’ROCKLADY’

May your gems always “Sparkle”