LAPIDARY DIGEST
Administered by Hale Sweeny (hale2@mindspring.com)
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This list digest contains the following message subjects:

1. NEW: Mottled Polish on Rhodonite
2. NEW: What is Rapid Polish?
3. RE: Polishing Obsidian
4. RE: Polishing Obsidian
5. RE: Stabilizing Turquoise and Opal
6. RE: Stabilizing Turquoise and Opal


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<MSG1>
Date: Mon, 30 Jun 1997 08:38:00 +0900
From: bodhi@his.com

Subject: NEW: Mottled Polish on Rhodonite


My husband recently polished some Virginia rhodonite that looked good from
a distance, but up close, the surface appeared mottled or somewhat like
orange skin. Does anyone have any recommendations for getting an even
polish?

Cathy
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<MSG2>
Date: Mon, 30 Jun 1997 00:03:23 -0700
From: friesenr@ix.netcom.com

Subject: NEW: What is Rapid Polish?

On a different thread, does any one know what "rapid polish" is. I have
found it to be a very good polish but I would like to know more about it.

(Editor's note: I cut this from Friesen's response on "Polishing Obsidian",
below, to start it as a new thread.)
======================================

<MSG3>
From: DEZIGNS <dezigns@mwci.net>
Date: Sunday, June 29, 1997 6:49 PM

Subject: RE: Polishing Obsidian

Trish Councell <Tagia@aol.com> asked in the #12 issue:

<<Are there any tricks to getting a high polish on an obsidian cab?
I've been using diamond 325, 1200, and 50000 but it still seems a little
cloudy.>>

I have found that if you run 2 tablespoons of Tide (flake style) (per 12#
tumbler) in between the different grits it will clean them nicely and
takes a lot of excess grit that is left on the stones....even when you
think you have it all off. I also use rubber bands in all of my tumbling
as a cushion. They are easier to clean and to remove from the stones.

There is a new polish on the market for Obsidian, called M-5 available
thru Johnson Lapidary, P O Box 4528; Sparks, NV 89432 (Phil & Emma
Johnson).... I have tried a number of times to reach them to no avail ...
phone number is 702-476-0152. I haven't tried this summer though.

Hope this will be of some help.

Geri
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<MSG4>
Date: Mon, 30 Jun 1997 00:03:23 -0700
From: friesenr@ix.netcom.com

Subject: RE: Polishing Obsidian

My experience with students is that they almost never get the sanding done
adequately. Obsidian seems to show the fine sanding scratches, especially
600 grit, as a haze that won't polish out. A ten power glass will usually
show the problem, although many students can't see it until it is pointed
out to them. More time on the 1200 grit usually takes care of the problem.
For the best results I like to add some time on 3000 grit and then polish
with cerium oxide or "rapid polish".

On a different thread, does any one know what "rapid polish" is. I have
found it to be a very good polish but I would like to know more about it.

Dick Friesen
friesenr@ix.netcom.com
======================================

<MSG5>
Date: Mon, 30 Jun 1997 05:26:36 -0400 (EDT)
From: Vybtl@aol.com

Subject: RE: Stabilizing Turquoise and Opal

Hi Friends:

(awww shoot!) Would one or more of you kind people please reach through
your monitor and slap me!? My posting reminds me why I'll never be a chef,
if the cook book is not open, it usually ends in the trash (dogs won't go
near it either). Thank You Hale for questioning me. I've now the book open
to the appropriate page.

Epoxy type: 330. Two parts, one hardener, one resin. Water Clear.
Acetone: One Pint.

Mix both tubes into Acetone, real well. Allow stones to steep for 7-10 days.
Swirl brew around about every other day (don't know why, but that's what it
says!). Remove and let set for a minimum of one week prior to cutting. Keep
jar sealed and it will last quite a long time.

Sorry to those of you who rushed out and got the wrong stuff, or too much of
it. %-}

Vincent
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<MSG6>
Date: Sun, 29 Jun 1997 23:36:51 -0700
From: friesenr@ix.netcom.com

Subject: RE: Stabilizing Turquoise and Opal

I ask a commercial processor in Tucson how he did his stabilizing and was
told that he used the same polycarbonate that is used in airplane windows.
He would not go into details but I would assume this would be done at an
elevated temperature and pressure. There are certainly several ways to do
it and the results vary widely, I have some you can carve with a knife and
some that will scratch glass.

>How does one tell if it's been stabilized? Rough form: Plastic like
>substance surrounding the stone, easy.

Not always true, sometimes it is tumbled clean. Since natural turquoise
is sometimes tumbled also, it can be a challenge. Best bet, buy from
someone you trust or don't pay more than stabilized prices to someone
you don't. If you cut enough of it you do get a "feel" for it, most
stabilized turquoise just "looks different" but even experts
get fooled sometimes.

>Cut form: Not so easy. A raw
>turquoise nugget will tug at your lip when you kiss it. This property is
>diminished when stabilized.

What you are feeling is the porosity of the stone absorbing the moisture
from your lips. With a well stabilized stone, you will get no more
absorption than any other piece of plastic. True gem grade turquoise is
solid enough for the absorption to be virtually undetectable. I don't
think you will see any of this grade of rough at a gem show, at
least I have not seen any in California, Quartzsite or Tuscon.

Bottom line, if the Turquoise is set, you will be hard pressed to
tell the difference in good material without testing. Again, buy
from someone you trust.

>Chrysocolla will do the same thing, except it will try to rip
>your lips off your face.

A little different story here (from turquoise). Both turquoise and
chrysocolla come in a range of hardness from chalk to 6.5-7. But
chrysocolla is copper silicate, with the hardness varying with
the silica content. As the hardness approaches 7 the absorption
approaches zero (it becomes chalcedony, and the price becomes
impossible :-( ).

Dick Friesen
friesenr@ix.netcom.com
======================================


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