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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 193 - Sat 1/9/99
2. REVIEW: The January Issue of Lapidary Journal
3. NEW: Need Info on Diamond Polishing Belts
4. NEW: Saleability of Opals with Imperfections
5. NEW: Orienting Montana Agate for Cutting
6. NEW: Spare Parts for Tumblers
7. NEW: Where Do Opalized Clams Come From?
8. Re: Questions about an Opalized Clam
9. NEW: Polishing Jasper in a Vibratory Tumbler
10. Re: Polishing Jasper in a Vibratory Tumbler
11. Re: Polishing Jasper in a Vibratory Tumbler
12. Re: Polishing Jasper in a Vibratory Tumbler
13. RE: Polishing Jasper in a Vibratory Tumbler
14. RE: Which Oil to Use in a Slab Saw?
15. RE: Which Oil to Use in a Slab Saw?
16. BIO: Paul & Catherine Gallagher
17. BIO: Margaret Malm


Subject: LapDigest News for Issue No. 193 - Sat 1/9/99

This is one of those days when I have nothing to say. So
just remember about hugs and expecially about having fun.
Now DO IT! (smile)


Subject: REVIEW: The January Issue of Lapidary Journal

December follow up teaser - For some reason I couldn't talk
my wife into letting me put a little smoky quarts into her
bread just for old fashioned fun. :) Confused? Check out
the December review or page 49 of the December LJ.

A 10" Tile Saw. Page 16.

Andy Oriel Talks about a tool usable in a lapidary which was
not even designed for it!! The MK-101 tile saw has a
1.5hp motor, water cooling, a calibrated conveyor table, and
a 10" diamond blade that is mass produced for the tile
industry so it is available at discount prices. Gem cutter
Lew Wackler calls this saw "a lapidary wolf in sheep’s

(JR's note: Does anyone know the price of this unit and what
replacement blades cost. Also where are they sold?)

Gems inside Gems Page 22.

Si & Ann Frazier have a great article on lapidary artist
Brian Cook. Brian has perfected the art of adding small gems
inside larger stones. There is a photo of a rutilated quartz
with two cavities stopped with garnet. They contain two
varieties of garnets and gold nuggets. The article talks
about how Brian takes great care to polish the inside of
the cavities. It also talks about how he uses 330 epoxy to
glue the "cork" in place. One look at Brian’s work and you
will want to head for that pile of clear quartz that you
bought so many years ago because the price was right.

A Sleepy Town Awakens. Page 48.

Mark Lurie has a large article on Tucson as it is just about
time for the shows to start. This article also contains John
White’s "Sort It Out" list of gem names. For example, if you
have seen someone selling sangre but didn’t have a clue what
it was, check out this list for the answer.

Shop Helps. Page 70.

June Culp Zeitner has a list of tips. One is about reducing
surface tensions. Understanding this process can help us all
get a better finished product in an accelerated manner. It
lists the surface tension of water (73 dynes) and
ethyl alcohol (22.3 dynes). JR’s note.

Does anyone have a list of our commonly used items and what
the tensions are? Would we find it useful?

JR Schroeder
J & J Jewelry

Subject: NEW: Need Info on Diamond Polishing Belts

I am interested in comments regarding polishing belts.
George and I bought a Genie (probably because the Guild in
our area used them in class). We do not like the
replacement wheels. They rusted in spite of our use of
water aid. We have been told that we should use mostly
belts. We are somewhat "uninformed about the choices in
belts. 3 M offers some fairly expensive diamond belts and
then they also offer some belts called trizac cutting belts.
We are hoping to get some feedback on what are the best
diamond belts that some of the more experienced cutters use.
We would hope to find some durable material.


Elizabeth Jones


Subject: NEW: Saleability of Opals with Imperfections


I'm finding myself facing a question that I guess most of us
lapidaries must face at one time or another: Selling some
stones to get more rough.

A few short weeks ago (mid-November), I cut my first opals.
I've always loved opal, and always thought I'd love to cut
it, but I was always afraid to. I bought some relatively
cheap rough at our local show, and managed to overcome my
fear enough to cut the stones. Much to my surprise, I found
that a couple of them are the prettiest white opals I've
ever seen.

And so another sunken-eyed, opalholic was born. I love the
stuff. Can't get enough.

My dear wife somehow managed to find me a large parcel of
beginners' potch-and-fire opal to cut as my Christmas gift.
I've found some very pretty stones in there, and I know by
looking around that the worst of them look as good as any
opals I see in commercial jewelry (Service Merchandise
(probably a dirty word to Jewelers) and other places).

Here's my problem: Most of my stones were cut to maintain
the largest possible area of fire in the stone. I cut
some to fit my templates, but more are freeforms. Most of
them have a small chip on a back edge, or are not completely
flat and uniform thickness. I've never seen fine opals that
are not set before, so I don't know if this is common.
The nature of the material, though, is that some of it comes
from thin pieces, and the only way to get good-sized, fiery
pieces is that some of them will be thin, some will have
uneven backs and some will have defects on the back. I've
done my best to make sure none of them have any cracks or
crazing in the stone itself, even though that meant grinding
away a lot of fire.

Is this common in opal that isn't machine produced? Do
jewelers work with this? So much of the stuff you see in
calibrated sizes looks like it was just cranked out of a
machine with the goal of being a predictable size, without
any regard to there being any fire left. Are my stones
with uneven backs and edges likely to be saleable?

I've never seen this subject addressed on the list before,
but I imagine that many lapidaries are faced with the need
to sell off some finished stones to help buy some new rough.
I'd appreciate any input.


Bob Lombardi
blombard@iu.net or blombard@freenet.fsu.edu
Bicycling, telescope making, optics, astronomy,
Radio Design, piano, SW and ham radio
Visit http://www.freenet.tlh.fl.us/~blombard
Bob: Have you considered backing them - either before or
after cutting? This would make cutting easier on the thin
slices, and would give the thin slices rigidity. It would
also even up the backs. If they are bezel set, you wouldn't
see the backing. Now, I don't want to take away from your
original question, but to add another one to it: Are backed
calibrated opals saleable?

Subject: NEW: Orienting Montana Agate for Cutting

I have some Montana Agate rough and I was wondering if
anyone could give me any tips on how to cut it so I will
get the best possible slabs. I would like to find plume or
pictures in it. Is there a certain orientation that
usually works? Or is it just trial and error?


Randy Aue

Subject: NEW: Spare Parts for Tumblers

The recent postings on tumblers reminded me of something.
My Thumlers Tumbler Model B needs a new belt and could use
some new bushings for the rollers and an extra liner. Any
ideas on where to order them from ? Checking around, I find
Lortone and Raytech everywhere and occasionally Thumler but
no spare parts.

(Ken: Thumbler's are made by Tru-Square Metal Products, P.O.
Box 585, Auburn, WA 98071. Their ads list an 800 number for
dealers as: 1-800-225-1017. I'd try them first. hale)

Subject: NEW: Where Do Opalized Clams Come From?

I got an opalized clam as a gift from someone who went to
Australia, but it has no label. Where exactly do they come


Subject: Re: Questions about an Opalized Clam

Responding to Hans Durstling's question about cutting
opalized clam, Gil Shea wrote:

[If it is a solid piece of Precious Opal it shows,
especially when wet, try Glycerin or a light oil, and look
the stone over under a bright light you should see the fire

I understand it is Gil's intention to suggest a way to view
the fossil clam for best appearance of color play. However
I want to emphasize that the use of glycerine is not usually
appropriate with opal. For such a viewing session it would
probably be fine but glycerine is hydroscopic and has the
potential to draw water molecules out of the body of an opal.

It is not an appropriate storage medium except for displaying
specimen opal that will never be cut or used in jewelry.

Additionally, on the subject of grinding without losing the
shape of the fossil, I have had good success using a Foredom
with a variety of diamond points for rough shaping of opal.
This is particularly workable with uneven color patterns,
removing sand, or for following color bands that run
unevenly as some have described in their opalized clam

The process is subtractive. Cut/grind away whatever isn't
desirable. This may be a way to preserve the shape of the
clam while exposing the fire. I have seen clams that showed
bright color from skin to skin and others that were patchy
or entirely (ulp) potchy. As with any opal, go slow!

Once a desirable shape has been achieved, I switch to
diamond paste and short pieces of 1/4" dowel rod - one rod
per grit, and work up through 1,200 or 14,000. The dowel
rods are easily shaped while spinning by holding them
against a steel file to get points etc for following the
opal surface. Use of these dowels requires a Jacobs type
chuck in the Foredom tool.

I then use cerium oxide for a final polish. I keep the
material very wet during all steps above especially the
final polish which is completed with the cerium paste on a
cotton wheel at about 3,500rpm.

I also use at least 10x magnification to examine the work at
each grit before moving up to the next finer grit. Cut a
little, look a lot!

Russ Madsen
editor The Opal Express
American Opal Society

Subject: NEW: Polishing Jasper in a Vibratory Tumbler

The 600 was slightly overkill for jasper, 500F does just
fine. I use a pre-polish which is actually low grade oxide
of some kind (get it from the local lapidary supply in paper
bags w/ no labels) for stuff that is not polished already
on the edges next. If it is polished on the edges, which is
likely with 600 grit and jasper, I use optical grade cerium
oxide to polish. This is overkill also, but it eliminates
the need for the soap bath that I feel is necessary using
cheaper polishes to get a really liquid polish.

Tim Fisher


Subject: Re: Polishing Jasper in a Vibratory Tumbler

Peter has some jasper that he has prepolished with 600 grit.
Make sure they are good and clean then polish them with
serium oxide. I always put a drop of Joy in with the cerium
oxide, make the water/polish combination the consistency of
thick cream, and run the polish cycle for about 7 to 10 days
in a rotary tumbler. If you are using a vibratory tumbler a
bout half that time but better to run them too long than not
long enough.

Once they are finished tumbling drain the polish off, cover
them with water, add a squirt of Joy and run the tumbler for
another day or two to make sure all the grit and polish is
removed. Then lay them out to dry in the sunshine. It is
interesting but sunshine helps to bring out the shine and
color in the rocks.

Dixie Reale

Subject: Re: Polishing Jasper in a Vibratory Tumbler

At last something that maybe even I could help with ;-)

Go straight to cerium oxide. In my experience, both of
these stones polish nicely, if they're nicely rounded
baroque shapes. Large flat areas don't seem to polish well
in my tumbler. The guy who taught me tumbling suggested I
use small wooden pieces that he provided. They're shaped
sort of like broken toothpicks; round-ish, maybe 2 or 3 mm
diameter and 1 cm long. They help fill in between the
stones and ensure that the CeO reaches all of the


Bob Lombardi
blombard@iu.net or blombard@freenet.fsu.edu
Bicycling, telescope making, optics, astronomy,
Radio Design, piano, SW and ham radio
Visit http://www.freenet.tlh.fl.us/~blombard |

Subject: Re: Polishing Jasper in a Vibratory Tumbler

We use vibratory tumbler for everything up to and including
pre-polish 600 grit. We then transfer the payload to a
rotating tumbler for the final cerium oxide or aluminum
oxide polish. Great success with this method. Shape is
maintained with vibration during smoothing grit-grind, and
polish with rotating tumbler is superb.

Alternatively, you can use the vibratory with 1" square
pieces of imitation chamois (the real chamois are too hard
to catch and are, I believe, endangered <grin>).

Hope this helps.

Bob Weeks

Subject: RE: Polishing Jasper in a Vibratory Tumbler

What do you want to know? :-)

I say, "go for it." Jasper and chalcedony are pretty easy
to tumble polish. I don't waste cerium on ANYTHING I
tumble, though. I use relatively cheaper tin oxide or other
stuff -- I forget, I bought it like five pounds at a time, a
while ago, and I'm not at home right now to look at what I
have. But I know I reserve the cerium for my buffing wheel.

If the rocks don't take a shine in your vibratory tumbler,
at least no harm should be done unless the tumbler gums up
and the rocks stop moving. Just let them run longer, if
necessary longer on prepolish and then try polish again.
I find 8-9 days on each flavor is good in my rotary

By the way, you can reuse both prepolish and polish
slurries. Separate it from the rocks into gallon jugs (say
through a strainer), let it settle, then pour off the clear
or thinly colored water until thicker gunk comes out. Shake
up what's left and reuse it. Add fresh compound to it
occasionally, maybe 1/3 or 1/4 of the full amount you'd use
with straight water. Works for me. Because of this I
seldom have to buy more prepolish or polish, which is partly
why I've forgotten what I'm using. :-)

Alan Silverstein

Subject: RE: Which Oil to Use in a Slab Saw?

Hello John,

Vegetable oils for lubrication.......Aha. The deep throated
roar of a finely tuned Manx Norton 500 single in full chat
as it leaps Ballaugh bridge, the excitement enhanced by
the unique 'track' smell of Castrol Racing oil.

Excuse my reminiscing, it is relevant. To prepare a race
engine that will be using a vegetable oil such as Castrol
Racing oil, first you have to completely strip every last
part and scrupulously clean them all to ensure that no
mineral oil AT ALL remains. Any trace will combine with the
vegetable oil to form a thick non lubricating gum which is
a total pain to remove, assuming you have anything left
worth cleaning, seizure is the usual result. A specially
prepared oil such as this will provide superior cooling and
lubrication than a mineral counterpart but cheap it is not.
I also think that synthetics may have replaced it by now
as I have not witnessed a motorcycle race for over 30 years.

Because of the necessary stripping and cleaning of the
equipment I would not recommend changing to a vegetable oil
even if you could be assured of superior blade life and have
a formula that won't turn rancid, breed bacteria or dry out.

Anthony L. Lloyd-Rees. ICQ# 15173706

web site: http://www.opalsinthebag.com

Subject: RE: Which Oil to Use in a Slab Saw?


I want to thank all of list members on their comments on
using vegetable oil in a slab saw. Went out yesterday and
was able to purchase baby oil for about the same price that
I was paying for a gallon of cutting oil. Cranked the saw
up today and cut a few thin slabs of quartz for some caps,
and I must say that the whole operation seems to smell a lot
better, and also look a little cleaner.

Thanks again for the input everyone.

John Campbell

Subject: BIO: Paul & Catherine Gallagher

Hello! We are new to this list and wanted to take a minute
to introduce ourselves. We began as simple rockhounds until
our love of minerals grew into a business. Now, we sell
Arizona minerals, many of which have been used for lapidary

We have the beautiful gem silica chrysocolla from various
mines around Arizona. We also have hard chrysocolla mixed
with malachite, along with red jasper, carnelian (a little),
petrified wood, amethyst, shattuckite with tenorite, "Bisbee
Ice" calcite, "Sleeping Beauty" turquoise, azurite, brown
and white chalcedony with occasional fire, "Bacon" agate,
and the unusual "Magma Mine Ore" - a copper-rich ore that
has bornite, pyrite, chalcopyrite, hematite and occasional
copper and (rarely) gold. Please take a moment to browse
our web site if you are interested. The address is

If you are coming to the Tucson show this year, we would be
happy to show our minerals to you. We will be visiting our
customers personally this year, or will show from our home
by appointment. Please e-mail or call to let us know where
you will be and what you would like to see and we'll get

Looking forward reading the postings on the list!

Paul & Catherine Gallagher
Gallagher Minerals

Subject: BIO: Margaret Malm

Hi! I'm a retired Eastman Kodak chemist now working as a
seasonal park Ranger at Zion N.P.

When I started working at Zion I developed a big
interest in geology, which led to my taking some courses at
Southern Utah U., including mineralogy. And mineralogy is
actually my main interest.

But I'm also trying to get going in silversmithing. And to
go with silversmithing I need to learn more about lapidary,
to go with it. I have not had a lot of training in either
field, and am eager to learn more.

I'm also very new at E-mail and the Web, so I hope everyone
will be patient when I goof!

Margaret Malm
Hi Margaret - Did you work at the Park? (I mean EKPark on
Lake Avenue)? I did for a short while and have great
memories of Rochester! Welcome! Don't worry about goofing -
just enjoy!! And if you don't understand something, ask
about it! hale
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