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LAPIDARY ARTS and FACETERS DIGEST
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Issue No. 301 - Friday, September 17, 2004
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Moderated by: Thurmond Moore III
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Committed to carrying on the fine works of
Hale Sweeny and Jerry Dewbre
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Hi all,

Here is this week's issue. Enjoy and have
a great weekend.

Thurmond
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Index to Today's Digest

01  RE: Synthetic Alexandrite
02  RE: Synthetic Alexandrite
03  RE: New Lap
04  RE: Faceting "Vaseline Glass"?
05  RE: Faceting "Vaseline Glass"?

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Message:01

Subject: Synthetic Alexandrite
Date: Fri, 10 Sep 2004 16:02:41 -0400
To: "LapidaryArtsDigest" <lapidary@caprock-spur.com>
From: "All That Glitters" <atggems@netzero.net>

To clarify, yes it is synthetic Alexandrite and NOT corundum.  Corundum
wouldn't have all the colors one sees in this;  Alex is polychroic.  Plus,
we have also done RIs on it and have sold it before in the past, so
Identification is positive - Chrysoberyl, Variety - Alexandrite.  We have
dealt with this for years and are familiar with the material.  We have sold
it overseas to Hong Kong, but this time, due to numerous requests, we are
offering it in small quantities, so people don't have to order a full Kilo
like before.

This is a boule and would be from the Czochralski Pull Method.  This has
less Cr content and therefore, the color is less saturated so one can cut
large (larger than 7mm) without it being almost black..  In fact, this color
requires larger stones to be cut.  We are happy with the previous pieces
faceted but wanted more info for those wishing to buy the rough to facet
themselves.  I have sent a piece to one of our US cutters to facet two
stones at different orientations.  Both are variations of green under
fluorescent lights.  We will see what comes back, but I think regardless of
the orientation, we have gotten a bright reddish pink under incandescent and
under the righ fluorescent, we get a purple with teal or other colors also
being predominant.  The price is right too for such an interesting gem.
(Price per gram is $7; the 99gram parcel is sold currently)
For those purchasing the rough and doing some cutting, we would love to see
the finished product if good photos can be taken.

Check out the boule, the faceted stone and the pieces up for sale currently.
Also, we discuss what the colors we see down the different axes with a
dichroscope.

http://www.atggems.homestead.com/files/Synthetic_Alexandrite_Rough.htm

Allen

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Message:02

Subject: New composite lap
Date: Fri, 10 Sep 2004 16:56:02 -0400
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: "Jonathan L. Rolfe" <jon@gearloose.com>

Hi Jon,  Your new prototype lap you announced on the USFG sounds like magic.
Sign me up if and when they go into production. Sounds like the ticket for a
"large stone" cutter.
 
I was going to post it here and on another group as well, but had so many
responses I chickened out and was afraid to even check my mail for a few
days.  It is like that when, on rare ocassions, I offer Redwing Seconds at
a discount.  People in realtime vs.digest mode swamp me in a matter of
minutes. I _like_ having people like my stuff, but even Messalina got tired
once in a while...haha.
I was looking for a COUPLE of people to test it as a "Peer review" thing,
because we are all grown up enough to take anything a manufacturer says
with a grain of Facet Grade Halite..Only the USERS' comments count.  Has
anyone ever heard a manufacturer say "This is a pretty good product- Not
too bad-Better than nothing!"

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Message:03

Subject: Synthetic Alexandrite
Date: Fri, 10 Sep 2004 17:04:54 -0400
To: "Lapidary Arts-faceting" <faceters@caprock-spur.com>
From: "Rock Peddler" <rockpeddler@comcast.net>

"A question. Is the material being offered lab grown corundum (simulated
Alex, not synthetic Alex), or is it lab grown crysoberyl (Alexandrite)?
  There is a vast difference.  It sounds from the description it might
be the former.  The synthetic (lab grown crysoberyl) alexandrite that I
have bought didn't look like it came from a boule.  Boule sounds like
corundum.  Please clarify. Thanks."

Regarding Jerry Newman's question (above), I haven't been reading the thread
so don't know what is being offered, but I do know that the "real" synthetic
alexandrite, that is, the synthetic mineral that is chrysoberyl, does come
in what is called a boule. It is a different shape than the synthetic
corundum or synthetic spinel boules. The synthetic chrysoberyl boule has 2
rather flattened sides and is wider. Cutting about 5 degrees off the C axis,
which is the long axis of the boule, gives the best of both colors, but you
can also get a good looking stone facing up on the C axis. I believe there
is occasionally some synthetic alexandrite that comes in a thin rod - this
is also synthetic chrysoberyl.

Jeanne Ridolfi - Rock Peddler
www.rockpeddler.com
www.bestrough.com - See our new LOW prices for synthetics
800-416-4348; M-F, 10:30am - 4:30pm, eastern time

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Message:04

Subject: Subject: Faceting "Vaseline Glass"?
Date: Fri, 10 Sep 2004 17:08:57 -0400
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: "Jonathan L. Rolfe" <jon@gearloose.com>

At 01:56 PM 9/10/2004 -0500, you wrote:
>Subject: Faceting "Vaseline Glass"?
>
>Has anyone faceted 'gemstones' from this material?
>
>Is there any inherent danger in cutting it as far as health wise?
>
>        I: Uranium compounds are inhalation hazards.  Alpha particle
> bombardment of the lung is the operative mechanism in Radon danger.
> (Radon and thoron decay into a host of alpha-emitting "daughters", and
> this transition is usually accompanied by a gamma ray.  Studies on
> uranium miners were thought to be conclusive at one time, till it was
> revealed they all smoked, so it is difficult to determine whose agenda
> was served by the study.)

The amount of uranium in this glass varies widely.  Recent samples of
contemporary manufacture have very small quantities, but I do have a large
dish of it, made in the 1930's, that has about 0.08% UO2 that will run my
geiger counters offscale at X10 and cannot be legally mailed or shipped.
For the safe cutting of these materials
see:  http:www.gearloose.com/radnote.html and decide if you want to cut
it.  There are things you need to buy:
1: An alpha monitor for decontaminating your machine and work area after
cutting.
2: A Nuclide certified respirator.


II : Vaseline glass is a lead glass, and some recipes call for ~30% PbO.


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Message:05

Subject: Vaseline Glass
Date: Fri, 10 Sep 2004 18:42:57 -0400
To: <faceters@caprock-spur.com>
From: "Beth & Doug Dover" <ddover@carolina.rr.com>

I have cut several pieces of the vaseline glass and found it typical of
other glass. It has an extremely low radioactivity level, about
background. It does glow very well and yes kids love it. You should
always cut wet anyway on glass and that is what I did on this. I roughed
on 600 and went straight to cerium on glass. Anything rougher than the
600 left lots of damage. The material is so soft it is no problem to
cut.

Doug

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