Edited and Published by Hale Sweeny
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Associate Editors: Geo. Butts, JR Shroeder, Steve Henegar
and Margaret Malm

This list digest contains the following message subjects:

1. LapDigest News for Issue No 251 - Wed 12/1/1999
2. NEW: Does Sandstone Crack Opals?
3. RE: How to Apply Cerium Oxide to Leather
4. RE: How to Apply Cerium Oxide to Leather
5. RE: How to Apply Cerium Oxide to Leather
6. RE: How to Apply Cerium Oxide to Leather
7. RE: Expanding Wheel, Belt Too Tight
8. RE: Expanding Wheel, Belt Too Tight
9. RE: Making Doublets and Triplets
10. RE: Making Doublets and Triplets
11. RE: Diamond Sanding Grit Between 220 and 600
12. Re: Diamond Sanding Grit Between 220 and 600
13. RE: Materials for Intarsia
14. Re: Materials for Intarsia
15. RE: Sources for Sintered Diamond Blades
16. RE: Crack Healer Recipe
17. BIO: Christina Broman


Subject: LapDigest News for Issue No 251 - Wed 12/1/1999

Someone (not on list) wrote asking whether I knew about the
'Friends of Jade'. I've never heard of it. Any of you know
about it? He was interested in their newsletter. If you
know an address for them, or anything about them, please
send it to me.

Also get a note from Stan Schubert asking about searching
the Archives. As you may know, we have a new search engine,
thanks to George Butts, which will search for any key word
in the text of the entire Archives. We will publish a set
of instructions for using it, in the next issue or two of
this Digest.

Take care of yourselves....


Subject: NEW: Does Sandstone Crack Opals?

Our local rock club's show was the weekend before
Thanksgiving, and (as always) I spent some time pawing over
opal and buying some rough. The dealer seemed knowledgeable,
but he told me something I've never heard before, and I
wanted to run it by the folks on the list to see if anyone
else knew anything about it.

He said that he believed that leaving sandstone on the back
of an opal would cause it to crack. As you know, much opal
comes with a layer of coarse-looking sandstone on the
surfaces that you must get through to find the opal. His
explanation was that the sandstone absorbed more water than
the opal, and this caused stress on the opal that eventually
led to a crack forming. I've often left sandstone on the
back of an opal, after smoothing it out. I'd hate to think
I'm condemning them to cracking.

As I say, I've never heard of this before. I don't recall
Downing saying this in any of his books, and they're most
of what I've read on opal. We have some long-time opal
cutters on the list, and I wonder if anyone else has heard
this, or believes it to be true.

I checked the archives, and found nothing to back up this

Bob Lombardi W4ATM in Melbourne, FL (ex-WB4EHS) or
Visit the ATM's Resource List-
Or visit me at

Subject: RE: How to Apply Cerium Oxide to Leather

I mix a batch of cerium (or other polish) with water in a
small 1/2 pint jar (or jelly jar with lid) and apply with
polish by dipping in a small paint brush and while the wheel
turns hold the brush against the leather disc. Apply enough
so that the wheel is evenly coated. While polishing if the
wheel seems to dry out, keep a squirt-bottle of water handy
and spritz the wheel to keep it damp.

Works good for me and I can polish several stones before
recharging my leather wheel.

Vi Jones

Subject: RE: How to Apply Cerium Oxide to Leather

<<I wonder if someone would describe how they load cerium
oxide on a leather belt (for opal in this case). I make
a bit of a slurry, but loose much more than I use.>>

There are several things you can try:

I have used a spray bottle for several years with mixed
results. You will still get over-spray but if you a 5 to 1
water to oxide, or more, you won’t lose much oxide. But
the spray head likes to clog.

Right now I am using Lab wash bottles. They allow a wider
range of mix ratios and don't clog easily but you also get
more thrown off.

You can make a paste mixture by using Ivory Soap and oxide.
Use a bar of soap and about an ounce of oxide. Cut the soap
into chips and dissolve in a small amount of water. Add the
oxide and cook over a low heat until you have a thick paste.
Just apply to the belt with your finger (before you turn it
on). It lasts quite a while before needing more polish but
the belt is "slippery" and hard to get use to, it does work

You can use "Colloidal Cerium Oxide"; it can be put on the
belt before you turn it on, also. But it is expensive enough
that you are better off throwing some off.

I use wheels rather than belts, they are cheaper if you can
use them. I usually keep the speed under 1000 rpm, that
keeps the amount thrown off to a minimum. At least I can
live with it.

Dick Friesen

Subject: RE: How to Apply Cerium Oxide to Leather

To Regis Galbach, regarding cerium oxide on leather - I
have a Diamond Pacific Pixie which uses a small round pad
on the right hand end of the machine for final polishing.
I have a leather pad to which I apply cerium oxide powder.
You don't need a whole lot of cerium oxide to polish your
opal. Most of mine gets flung off when I first apply it.
After the loose stuff gets slung around the room, there is
plenty left on the leather to polish.

I keep the leather wet with a spritzer and don't keep the
stone in contact too long or it will heat up and you will
lose your color. Hope that helps.

Jamie Peghiny

Subject: RE: How to Apply Cerium Oxide to Leather

Regis (and list),

I find that polish works best when well diluted with water.

Alternative one:

With the wheel stopped, use a sprayer (like for window
cleaner) and water to just dampen the surface. Take a small
amount (1/2 inch pile) of polish (cerium oxide) and put it
in half a coffee-cup of water. Stir it up. Sprinkle a
spoonful around the lap and rub it in with your fingers.

Turn on the wheel and start polishing. If you think you
need more polish, clean off the stone, dip it in the polish,
stir it around, and go back to polishing. The drop of water
with suspended polish hanging from the stone will recharge
the lap. Dipping also keeps the stone cool (don't let your
stone get so hot to avoid temperature shock).

Good for a couple stones before you have to turn it off and

Alternative two:

Start with the wheel off. Take a small amount (1/2 inch
pile) of polish (cerium oxide) and add just enough water to
make a thick, sticky paste. Smear it over an area the size
of a quarter in the center of the wheel.

Turn on the wheel. Periodically give the wheel a misty
squirt of water from a sprayer (like for window cleaner).
The mist and the rotation of the wheel will bring a little
(repeat, little) polish to the working area of the wheel.

Good for many stones before you have to recharge the thick
smear in the middle.

Alternative three:

Switch to a felt wheel for polishing opal with cerium oxide
and use as above. This is my usual method with opal.

Kreigh Tomaszewski
Please visit our family web pages at

Subject: RE: Expanding Wheel, Belt Too Tight

I will be interested to hear what other responses we get to
this also, I have the same problem. So far what I have been
able to find would indicate that the RayTech Drums are a
little smaller than some other brands. But in my case (6"),
they are too small. The belts spin on the drum before they
come up to speed and I may have to stop and re-seat them
several times before I can use them. When I tried the Graves
6" drums I got the "too tight" problem that George refers to.

On my 8" units a set of drums that were "just right" when
used two at a time. They were switched to a four drum arbor
and the same drums would then let the belts slip before
coming up to speed.

It really is annoying, I hope someone has an answer.

Dick Friesen

Subject: RE: Expanding Wheel, Belt Too Tight

A long term solution would be to talk to the makers of the
belt and wheel. The belt manufacturer should know of the
difficulties you are having. Ask them for the name of a
wheel maker that their product works with. Make sure you
let them know that you are taking belts off and on. They
may want the product to fit tight as some expand with use.
Also let the wheel maker know of your problem. They may be
able to change things in the future.

I had this problem with the older silicon carbide belts.
My solution was to take a large diamond file and turn the
wheel down. I turned it down on the shaft it ran on. Make
sure you use a mask, have plenty of ventilation and check
to see that there is no one around. The file I used was
from Sears. I'm sure you can find them at discount
hardware outlets on the net.

Good luck
Steve Ramsdell

Subject: RE: Making Doublets and Triplets

There is an new opal cutting video and book package by
Australian Greg Pardey, long time respected cutter to the
opal industry which shows exactly how to cut solids doublets
and triplets, step by step, on video.

He also demonstrates his unusual spin and hatch shaping and
polishing technique and offers numerous valuable tips on
equipment and Lightning Ridge black opal. This package is a
must for serious opal cutters and beginners. This book and
video package can be obtained through many US distributors,
or via my website.

Hope this helps.

Keith Rigby
phone: (61) 2 98163221
fax: (61 2 98177883
Address PO Box 58 Gladesville 2111 Australia

Subject: RE: Making Doublets and Triplets

Hi John and everyone,

The types of stones you are asking about are very simple,
but are not tumbled. We cut them on wheels, drums, flat
laps or even faceting machines!

A doublet is a dome shaped opal (cabochon) that is backed
by a supportive stone for reinforcement and sometimes to
enhance color in the opal. The 2 stones are glued together
and treated as one piece.

A triplet is the same principal applied to a sheet of opal,
which is sandwiched between a backer (opaque stone) and a
quartz cap (domed) on the top to display and protect the
opal sheet.

They are very attractive and much less expensive than an
opal solid. There are several books that will provide
step by step instructions and if I can dig mine out
(renovations, surgery, boxes, chaos!!) I will send names
and authors. Maybe someone will save me and send them

I have always found opals intensely satisfying to work
with, a soft touch, easy to polish and Oh my, what lovely
results! You will be hooked, as are a lot of us!


Subject: RE: Diamond Sanding Grit Between 220 and 600

Crystalite has a metal bonded 400 grit belt but I don't
think you would have much luck putting it between the 3M
220 and 600 grit belts. 3M has a resin bonded 500 grit but
it is listed as a 30 micron belt, the same as their 600 grit
(30 micron) cabbing belt. I use the Crystalite 220 and 600
resin belts and I have not felt the need for a 400 grit
step. I have the 3M cabbing belts and I think they wear out
too fast, if you have had yours for a while that may be the
problem. The factory, at one time, included a warning to
keep the belts under 600 rpm. The new belts I have no longer
carry the warning but I think it still applies. These belts
have some other characteristics that make them better suited
to specialized rather than general lapidary work (see the

3M has a new series of resin bonded belts that I haven't
used so I can't comment on them, the sales department
thinks highly of them ;<).

RayTech also makes a set of 8" belts and has a 325 grit
belt but I think they are too stiff for general use (they
work and you might like them).

Eastwind has 320 grit and a 400 grit diamond belt but I only
have the 220 and 600. Again I didn't feel the need for the
extra step. They seem to be good general purpose belts but I
haven't had them long enough to do a life test. I had a
defective 8000 grit belt but It was replaced with no hassle
and I haven't had any problems with the replacement. They
are a little cheaper than some of the other belts so are
worth looking at.

I like the Crystalite belts and for a little more the
Diamond Pacific Titan Nova wheels for general lapidary use
in an 8" system.

Dick Friesen

Subject: Re: Diamond Sanding Grit Between 220 and 600

Hi Larry,
Bob uses 400 grit between 220 and 600. Makes life much
easier. He also uses a lot of used 220 and all of his
belts for different jobs. You just have to experiment on
different stones. But, yes, you do want to use 400 grit.

Micki Bleily


Subject: RE: Materials for Intarsia

I am sure that fiber optics would be pretty in intarsia.
However, if you would be planning in exhibiting your
finished pictures in competition at the Federation
affiliated shows in the United States , I am pretty sure
that you can use only naturally occurring material. In
fact, if coloring is added to the epoxy between the stones
for accent it should be in the form of rock powder. Is
that correct?

Rose Alene McArthur

Subject: Re: Materials for Intarsia

Lapidary Digest (many thanks to Hale) has an associated web
page ( which
contains links to members web sites. Many of them offer
lapidary materials for sale. In fact, it is quite possible
that anything one desires can be found. I found a rock shop
and associated web page (
under Gem Stone Rough) that offers white potch opal and red

This list of links is WAY COOL and I would like to remind
everyone of its existence and encourage all fellow list
members and lapidaries to research the list for your needs.
There are also personal web pages where members display
their craft. Let me tell you "there is some very beautiful
work displayed". Several hours, maybe days, of pleasurable
and interesting viewing are available. Try it!

Paul Boni
Boulder, CO

Subject: RE: Sources for Sintered Diamond Blades

Nasim Ahmad <> wrote:

<<I am looking for manufacturers or suppliers of quality
sintered diamond saw blades (U.S. or European).>>

Hello Nasim,
This is a company which makes all kind of stone cutting and
carving tools and machines:

Hauptstr.139 a
Idar-Oberstein 2, Germany
Fax: 6781-41123
Tel: 6781-43087

Recently they have changed their names to:
WINTER Werkzeugmaschinen GmbH & Co. KG
Postfach 12 27 45 -55719
Idar-Oberstein Germany
but I believe the fax and telephone are the same.

Kind regards from Istanbul,

Oya Borahan
Nasim: American diamond blade manufacturers are listed in
the Buyer's Guide published each year by Lapidary Journal.

Subject: RE: Crack Healer Recipe

<< About your UHU adhesives: possibly the first one will
work. I do not think the second or third ones will work for
this crack healing application. Why not try the first one?
Add the contents of the two tubes to the acetone, and try
it out! And let us know how it worked.>>

Dear Hale,
I tried the first and second one in different pots in
acetone. Unfortunately the glue turned cloudy like jellied
milk when I put them in acetone. I took my stones out
immediately but am having trouble getting rid of the sticky

Kind regards from Istanbul,

Oya Borahan

Subject: BIO: Christina Broman

Hello fellow rocklovers!

Been subscribing to the Digest for a while now and
thought I would introduce myself. I cut cabochons and
make jewellery in Stockholm, Sweden.

I have loved rocks since early childhood and I find great
pleasure in both working with and collecting stones. After
having taken a degree and tried a few different
occupational paths, I decided to make my artistic work my
full-time occupation, figuring that would be the most
fulfilling choice for me - and I have not regretted it!

I have a newly opened homepage at C H Broman (if the link
does not work, it is to be found at, where I show some of
my cabochons and jewellery.

Wishing everybody Happy rockcutting and a Happy Millenium!
And my thanks to Hale for a great Digest!

All the best,

Christina Broman
If you want to see some nice work - and see some rocks I
had never heard of, look at her website! hale
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