I would sure like to see an AA spectrometer reading to be sure.
A relatively easy way to separate black jadeite from hematite is
refractive index. Jadeite is 1.66 - 1.68, while hematite is 2.94 -
3.22 Since standard refractometer cannot measure above 1.8, if one
get
“over the limit”, it is surely a very good indication of hematite.
Leonid Surpin
After writing the above I did a little searching on-line and found a material being sold here in the U.S. that exactly matches your description
I like how people here jump in to ID a stone without seeing it…
I’m serious, it’s like a detective story, and I can see how many
people enjoy it. Perhaps the URL is this:
http://www.zbestvalue.com/bj11.htm
Just Googled black jade from Australia…
Hi all, I have seen this material at gem shows in New Zealand. I
bought some from the finder / dealer and he had identification sheets
from gemlabs to prove it was jade. I also know some carvers here who
cut it and know it as jade. It has that distinct red crust on it, I
seem to remember it wasin an iron rich area, so this could have come
from its surrounds perhaps? It was a few years ago and I cant
remember to much more, Im sure some of the Australian gem clubs could
put you on to the finder to get his
Best wishes,
Philip Wells in New Zealand
I like how people here jump in to ID a stone without seeing it... I'm serious, it's like a detective story, and I can see how many people enjoy it.
I cut and sell gems so I do due diligence on gem ID. I know a bit
about gemology as well. The URL I had in mind (I forgot we could post
them here) is this:
It matches the description perfectly right down to the brick red
exterior, and is being sold as Australian black nephrite. I may order
a slab and test it to satisfy my own curiosity if the original poster
verifies this as the material in question.
Rick Martin
Or maybe this: http://www.gem.org.au/jade.htm If you’ve been told
its nephrite then it’s most likely from this deposit…
Cheers, Thomas Janstrom.
Little Gems.
http://tjlittlegems.com
There was an interesting article in the Professional Jeweler, October
2001 issue entitled Bountiful Black written by Robert Weldon, G.G. It
discusses Black Nephrite Jade from Nevada as well as Australia.
Perhaps the URL is this: http://www.zbestvalue.com/bj11.htm
Very close John, except if you look at the jagged edge with the red
color. The jagged shape implies a grain to the material. This is
typical of nephrite. I don’t think this is my material. My material
weathers with a flat planar surface. Also, my material has no grain.
It breaks easier than any nephrite that I have seen and my material
has a semi-conchoidal fracture. It shows no indication of a
fibrousstructure.
The URL I had in mind (I forgot we could postthem here) is this: http://www.greatrough.com/rough_jade_black-nephrite.shtml
Bingo Rick, this looks exactly like my material. I hesitate to say
that it is because I can’t see it first hand. Notice the
semi-conchoidal fracture on the top edge of the lower left stone
which is partly obscured by the shadow cast by the stone above it.
Also notice the angular blocky shapes which is typical of this
material, but not of nephrite. Please understand that this may not
actually be the same as my material and that I am not saying that
this dealer is selling a stone that is not nephrite. I am not
qualified to make that judgment; I am not just saying that to avoid
any liability.
How about this - and I mean this for everyone, not just those who
posted here - Don’t buy things that you want to re-sell until you
have the knowledge to accurately assess their genuineness, quality,
and value. I can’t imagine buying pieces of ‘something’ from a
random table at a gem show and taking the seller’s word for what it
is and selling it as such. Sure, if you want it for yourself, and
don’t care about anything but ‘the look’, buy whatever you like. When
you buy for sale, or to make something that will be sold, you need to
be SURE it is what you are selling it as. The law is not forgiving
when it comes to false representation, whether it is intensional or
not. When your customer returns demanding to trade their piece for
the real thing, and the real thing is 10X what you sold the piece
for, be prepared to make good.
If you don’t know your material, KNOW YOUR SELLER, and make sure they
have the knowledge and years of experence to back it up. When you
look at a piece of ‘black jade’, ask the dealer how they know it is
really black jade, what to look for to confirm the identification,
and what their policy is for items that have been mis-identified.
Then get real contact for them - not a PO Box or cell
number, those can be changed at a moments notice.
Lee Cornelius
Vegas Jewelers
That photo looks geologically similar to the outcrop in the photo I
saw, that is, looking at the angle of the joint spacing between
boulders, approximate scale, judging from the people in the photo.
That makes 2 pictures I have seen of the deposit, in one, the jade
is covered in a rust red crust, in the other, the boulders are
smooth, with little limonite evident.
I have material representative of both deposits, now with all of
this discussion, I will have to throw one of the larger chunks (75
pounds or so) into the 24" saw, and see what happens.
Perhaps I will have to purchase a larger block, 200-500 pounds, or a
larger slab, for a project I am working on.
warm regards
Mark Zirinsky
From: "Lee Cornelius" Don't buy things that you want to re-sell until you have the knowledge to accurately assess their genuineness, quality, and value.
You give very good advice and nobody will go wrong following it. I
usually follow this advice myself, but the circumstances enticed me
to do it differently this time. I bought the material because there
are several dealers selling this material and so far, everyone that I
found calls it nephrite (jade) from Australia. With so many selling
it, I expected to find anexpert who had experience with it. It looks
like tons of it are moving into the market place.
I purchased it because I judged it to have superior lapidary
properties. Now that I have worked it, I appear to be correct. It
polishes to a beautiful absolutely black gem.
A summary of properties:
Weathers to a solid brick red color.
Weathered pieces are blockly with flat surfaces.
Semi-conchoidal fracture.
No grain.
Absolutely black, not dark green.
My impression is that it chips easier than nephrite.
Sold by several dealers as nephrite (jade) from Australia.
Anyway, if an expert wants to try to identify this material, contact
me offline. Maybe a quick sample to the right person is the answer.
Calvin Smith
I can’t believe this discussion is still going on. A simple RI test
should at least get you in the ballpark. You don’t know any jewelers
who have a refractometer?
Daniel R. Spirer, G.G.
Daniel R. Spirer Jewelers, LLC
I can't believe this discussion is still going on. A simple RI test should at least get you in the ballpark. You don't know any jewelers who have a refractometer?
Yes, Daniel, he does. Calvin brought me a sample a couple of days
ago and I’ve been working with it as time has allowed. I’ve checked
RI, SG and all other properties I can measure. I have yet to find
time to grind a super-thin section to check the color of light
transmission through it but that’s coming, along with more time at
the microscope.
I’ll report my findings, which may not be conclusive, back to him
when I’m done and he can post them here if he wishes.
Rick Martin
I can't believe this discussion is still going on. A simple RI test should at least get you in the ballpark. You don't know any jewelers who have a refractometer?
thought that there was overlap for refractive index (RI) with
nephrite and some simulants. That is why I was hoping that somebody
who was already familiar with this material and knew of an ID from
more extensive tests would come forward. If you believe that a
positive identification can be done with a simple RI test, then
contact me off line with a mailing address. I will send you a sample.
I believe that you are well known in this group with a good
reputation.
Calvin Smith