Edited and Published by Hale Sweeny
Web Site:
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. 226 - Mon 8/16/1999
2. NEW: Etching Stone
3. NEW: Gem Materials from Texas and Bermuda?
4. RE: Looking for Book(s) on Agates
5. RE: Looking for Book(s) on Agates
6. RE: Looking for Book(s) on Agates
7. RE: Looking for Book(s) on Agates
8. RE: Polishing Peridot
9. RE: Filling Cracks in Dino Slabs
10. RE: Rainbow Obsidian Structure and Colors
11. RE: Rainbow Obsidian Structure and Color
12. RE: Rainbow Obsidian Structure and Color
13. RE: Mineral Oil as a Trim Saw Coolant
14. RE: Does Alunite Need to be Stabilized?
15. RE: BIO: Peter Plantec
16. WTB: Gritabrade Lap
17. WTB: Flint for Flintknapping
18. WTB: Apache Junction Jasper and Zebra Jasper
19. FS: Sphere Machines
20. FS: Yellow Cat Petrified Redwood


Subject: LapDigest News for Issue No. 226 - Mon 8/16/1999

As most of you know, I jealously guard the restricted scope
of the Digest, strictly limiting topics to lapidary items
(except when I want to violate it! [smile]) However, we do
not do our cabbing and intarsia, etc., in a vacuum. Most
items I make wind up as (hopefully) wearable art. And this
means that more must be done to them when the polishing is
through; they may be mounted in a silver constructed or
purchased setting, or wirewrapped. And we, on this list,
completely ignore any problems connected with the mounting
of our stones.

I'm not about to change this, but something I saw at the
EFMLS Convention show should be brought to your attention.
One booth was advertising a wirewrapping magazine which was
really well done. Three wirewrappers from Canada produce it
and each issue has complete instructions and photos for two
wirewrap projects - one for the beginner and one advanced -
and this alone would seem worth the price of the magazine,
but it also has other items, news, bios of wirewrappers, and
so on. The thing which really caught my attention were the
wirewrapped designs. Many wirewrappers seem to overdo their
projects with ornate swirls and curlyques of wire, which
overshadow the thing they are wrapping. Not their designs -
they are mostly simple and elegant and very attractive. And
I would be proud to have anything I have made, wrapped in
one of their designs.

For more information about their magazine, visit their web
page at

I will be at Wildacres starting next Monday 8/23 through
Sunday 8/29, so there will be no Digests published in that
period. I will be home for a week, then off again to
Wildacres for another week.

You guys take care of yourselves, and hug and kiss the ones
you love - you can never overdo this!! ...and have fun!!!


Subject: NEW: Etching Stone

I'm looking for the best technique to use for a couple of
my upcoming projects. I need to etch a line drawing and
some script -- both with fairly fine detail -- on stone.
For the particular projects I have in mind, the stone will
be jade, though later projects use other stones (agate,
jasper, quartz, etc.). The depth needs to be around 1/32"
deep and undercutting is okay as I intend to fill it in
("inlay"?) with gold (24k leaf or amalgam). Suggestions?

Shawn sent this to several mail lists and they have already
published the replies. Rather than reproduce them all here,
I will summarize them below. Please send in your response
if you have something to add to the following:

There are two methods of doing this: chemical etching and
mechanical etching (e.g.; sand blasting or cutting with a
diamond tool). The only chemical which will do a fast job
is probably hydrofluoric acid, and this is one of the most
dangerous and insidious chemicals in any laboratory.


If you wish to etch into a carbonate such as limestone, you
can use hydrochloric acid, but exercise extreme caution. HCL
is also a dangerous acid.

Silicates or quartzes such as quartz or obsidian and jasper
will react much as does glass; there are hobby etches which
contain HF in very dilute amounts, and these are sold in
many hobby stores for etching or frosting glass. The one I
have used for etching designs into obsidian or quartz bolas
is named Armor Etch-All, and is sold in many hobby shops and
in many art-glass shops. It contains 1% HF, and comes as a
thick paste, which is more easiily handled than a liquid.
You may make a mask from wax or from one of the rubber
masking materials sold for this purpose. Again, look through
the literature at hobby shops for "how-to-etch" designs into
glass. This is a slow method, and may require 24 hours or
more, with two or three applications, to get a satisfactory
etch.... and even then, it still will be a very shallow

You may want to put the material being etched under a lamp
to make it warmer; reaction rates double for every 10 deg.C
increase in temperature.

I think that sandblasting is the best bet to get your design
cut that deep. Many art-glass stores have sand blasting
equipment setup which they rent on an hourly basis. They
also carry masking material from which you may cut the
design, and the mask self-adheres onto the material to be
blasted. Our art-glass store owner trained me in the use of
the equipment and masking material, as a service.

If no art-glass stores are nearby, try a company which
makes grave stones; these are done by sandblasting, too.

I have never sandblasted any material except quartzes, and
I used silicon carbide grit for that. Alumina should also

The last method is to cut the design with a high speed
rotary tool with diamond pointed tools. For me, this would
be used only as a last resort, as my hand is not that

Subject: NEW: Gem Materials from Texas and Bermuda?

I have a client from Texas who is marrying a lady from
Bermuda, and they would like some materials in their
wedding rings which are native to their respective lands of
origin. Does anybody know of any gem materials which are
found in these places?

I figure Texas has petrified wood, probably some agates-
any other suggestions, or sources?

Are there any Gulf Coast natural pearls still available?
Bermuda must have some coral, although I'm not sure if it
is gem quality- are there any stones from there? I know
Larimar comes from the Carribean area, but I'm not sure
from where.

I'd be glad of any input from people familiar with these

Andrew Werby
Sculpture, Jewelry, and Other Art Stuff

Subject: RE: Looking for Book(s) on Agates

One of the finest books on agates that I have seen is "The
Agates Of North America". It was compiled and edited by Hugh
Leiper. Published by The Lapidary Journal.

Not only does it give you some very fine pictures of various
Agates, it also tells you where to find them. I am not sure
that the book is still published. It may be available from
some of the different lapidary Shops.

Though most of the time I lurk, I really enjoy the Lapidary

Best to all.

Elmer Panasuck
If you want to buy this, or other out of print books, check
the used bookstores on the Web. I use: Advanced Book
Exchange at (, and
MX Bookfinder at ( You should
be able to find it at one of these sources. Their prices
are from $7.50 to $10.00 for used copies of this book. hale

Subject: RE: Looking for Book(s) on Agates

Brad Cross does have a book on the Agates of Northern
Mexico. He also said he will have a new book coming out in
a few months, same subject but I believe by a new publisher,
possibly in a different format.

He can be reached at

Paul Bordovsky

Subject: RE: Looking for Book(s) on Agates

The author of "The Agates of Northern Mexico" is Brad L.
Cross. As indicated in a previous message, Brad does live
in Austin, TX. He recently made a trip up to Dallas to give
a presention to our club, the Pleasant Oaks G&MC of Dallas
and had several copies of the book with him. I do not know
if the publisher has any, but it is published by Burgess
International Group, Inc., Burgess Publishing Division.
Their address is 7110 Ohms Lane, Edina, Minnesota 55439-2143
and their phone is 612-820-4561. The Library of Congress
ISBN number is 0-8087-7282-1.

I found the book to be excellent.

Don Shurtz

Subject: RE: Looking for Book(s) on Agates

Hi Hale, Steve, the other editors, list members and agate

After my holiday in Idar-Oberstein, Germany, where a lot
of agates can be found, I read Steve's message in the List.
I'm wondering if you, Steve, looked at the Agate Page and
it's Agate Bibliography at www:\ A lot of books
are described there.

I searched for books I own and I found several; some of them
are in German and if you don't understand the language, the
pictures are great.

*Banded Agate; Origins and Inclusions by Roger K. Pabian
and A. Zarins. Can be bought at the University of
Nebraska-Lincoln (www:\
*Agate; Microstructure and possible origin by Terry Moxon.
Can be bought from Terry at:
or from his homepage: homepage:
*Achate by G. Plodowski and R. Werner.
ISSN 0341-4078
*Das Problem der Achatgenese by Michael Landmesser
ISSN 0341-6992
*Achat by H.J. Blankenburg
ISBN 3-342-00304-9
*Achate, Bilder im Stein by J. Arnoth.
ISBN 3-85815-143-2

When you want to know more just mail me or the Lapidary

Robert M.B. de Jager,
Groningen,The Netherlands.

Subject: RE: Polishing Peridot

Well, golly, I tried Linde A and it worked like a charm. I
started out using lots of water, trying to avoid heat
buildup (you may recall that chunks were pinging from my
peridots whilst I was attempting to put a polish on them
with cerium oxide). That turned out to be unnecessary as
the polish came quickly without much pressure. I managed
to resurrect most of the ruins I had been working on.
They're just slightly smaller than originally anticipated.

I bought two how-to books. I will now refrain from
reinventing the wheel.

Many, many thanks to all who helped!

Dana Carlson

Subject: RE: Filling Cracks in Dino Slabs


While epoxy will work for the cracks in your dino bone, you
probably will get better results using a commercial
stabilizer designed for filling cracks, and for penetration
into the material. We use Opticon and have good results,
although someone out there may have a better solution. It
is available from most any lapidary supply; if you need
specifics on how to get some, contact me off

Welcome to the digest, you will love it!


Subject: RE: Rainbow Obsidian Structure and Colors

Hi, Hale. I can't give you a source on this (somewhere from
the primal rockhound collective knowledge) but I think the
color in rainbow obsidian is from light playing off
stretched out bubbles of gas trapped in the glass.

The amount and size of the bubbles determine the type of
obsidian you have, with pumice (a lot of big bubbles) at
one end and rainbow (very small bubbles) at the other.
Sheen obsidian falls in between.

The stretch and orientation of the bubbles play into the
different "rainbow" effects as well as the chemical content
of obsidian. The bands on the side of the stones are just
the different bubble concentration/size zones in the flowing

Different collecting sites (as well as area at a given
site) have different size bubbles, degree of stretching,
mixing, banding, and cooling which lead to the different
types of rainbow. By the way the samples you have are still
flowing - very slowly (definition of a glass).

Buy the way, cut your slabs a little thicker than usual
because the glass tends to get more surface micro fractures
during grinding than most stones, which need to be sanded
out before polishing.
Good luck,

Jerry Kinder

Subject: RE: Rainbow Obsidian Structure and Color

Hello Hale

I've done a little experimenting with Rainbow Obsidian but
by no means am I an expert on the geological makeup of the
material and therefore I cannot explain the whys and
wherefores. I use Rainbow Obsidian for manufacturing golf
putter heads.

The lines or grooves around the outside of piece usually
represent the changes of color, the closer together the
more of a rainbow effect you will get, and the farther
apart they are they may only show the two main colors of
purple and green along with the black. The outside matte
finish is due to weathering and must be removed in order
to see the grain of the material.

The main thing is what is the piece going to be used for.
If it is for cabs and jewelry you want to get a piece with
the lines close together and cut at a perfectly 90 degrees
to the lines and then it may shine in both directions. If
the lines or changes of color are farther apart you will
not get the multicolor of the rainbow on a small piece.

The most popular use of rainbow obsidian today is contouring,
the handworking of the top of a good sized piece. This is
usually done with the outside in its natural shape only
cleaned up and polished. I would say a minimum size of 6"X6"
and preferably an irregular shape is best. The top is then
handworked high in the middle and tapering off to the
outside edges exposing the changing of colors as it goes
down. Irregular shaping on the top produces better color.
When completed polishing the pieces are a beautiful work of
art and they fetch a good price.

The contouring can be done with the MK Diamond
"Wet Grinder/Polisher" model # MK-1503. It has 3" & 4"
diameter Diamond discs with quick disconnect water feed.
The pads go from 50 grit on up to 8500 micro grit.

I am not connected with MK Diamond and am not advertising
their product. I just found out about them when I researched
their buying of the Star Diamond Co. and their grinder is
just the ticket for contouring rainbow obsidian and the ends
of petrified wood logs. See them at

I hope this will be of some use to you and it is not too
confusing. The written word cannot replace the actual deed.

Ernie Ogren
The Geode Man

Subject: RE: Rainbow Obsidian Structure and Color


I would like to let you know some of the things that I
have found out about some of the various "exotic" obsidians.

In general, the rough pieces will have some kind of a
striated rind on them. These "grooves", when present, can be
used to orient the stone when cutting. If no striations are
noticeable, then trial and error are needed to find the
proper orientation, this is best done by grinding and
polishing several windows in the rough to see the
orientation of the effect. Or you can whack it with a hammer
to knock a chunk off!

The "Sheen" types (Rainbow is one of them) are best oriented
so that the cut is parallel to the exterior grooves (or
effect). This holds true for the "Flash" types of obsidian
in general, but I have had wonderful effects by offsetting
the cut of my slabs by about 10-15 Degrees. This causes the
blade to cut across several of the internal layers and gives
Life to the center of a flat-top cab.

Because the internal striations are not necessarily parallel
to the ones that show on the exterior, I recommend that you
examine each slab as it is cut and make adjustments as you

Have fun, that's what it boils down too anyway.


Work like you don't need the money.*
Love like you've never been hurt. *
Dance like nobody's watching. *


Subject: RE: Mineral Oil as a Trim Saw Coolant

<<You might want to compare the price you pay for mineral
oil against the price you would pay for the same quantity
of a saw oil like Almag or that other one - whose name
escapes me at the moment.>>

Are you thinking of Pella A?

Thanks, Ray - yes, that is it! PELLA-A!! hale

Subject: RE: Does Alunite Need to be Stabilized?

Another opinion on Alunite: cut in the shape of a heart,
wirewrapped and accented with garnet beads it's quite
lovely, a bleeding heart.

Desires wrapped in wire
Debbie: Thinking about the alunite slabs I've seen, I can
visualize the bleeding heart pin or pendant and agree it
would be most attractive! A good use of this material.hale

Subject: RE: BIO: Peter Plantec

((I'd love to hear from other opal lovers about good sources
that won't kill you with their prices. Peter Plantec))

Hi! Well, you're on the right track already just by
LOOKING for good sources! ;-) There are several good
sites on the web and mail order for quantity opal, but the
absolute best place to find what you want is to go to gem
shows and look over what the dealers have brought.

Since you live in the L.A. region, I would DEFINITELY
encourage you to go to a meeting of the American Opal
Society. <<>> LOTS of
very friendly people who are always willing to answer
questions and to help out with any sort of problem!

A good place to start looking for rough is the AOS annual
show in Anaheim, November 6, 7. The website has more
details. You won't find a better gathering of people
selling opal anywhere! ;-)

Larissa A. Williams
Sunnyvale, California

Subject: WTB: Gritabrade Lap

Anyone out there heard of a lap called "gritabrade"? It's a
metal lap about 1/8 thick covered with various diamond grit
(100, 200 etc.) It is used to rind flat areas in rocks or
slabs before slabbing. I got mine from my dealer, who has
since retired and moved away. I am about ready for a new
one. Any ideas as to who may still sell them?

Mack Lingenfelter

Subject: WTB: Flint for Flintknapping

I am new to the group, having joined about 6 or 8 weeks ago.
I live in Queensland, Australia. I have the only claim in
Agate Creek for agate and I have a claim at a place called
Yowah for yowah nut opal, which I will start mining within
about 6 weeks, I hope.

The main reason for contacting you is that I need some
very large pieces of flint. I have a customer who wants to
make knives. The pieces he wants are at least 8 inches long
or longer, 6 inches wide or wider, and 4 inches deep or
deeper. Colour is not important. Can any of your members
out there help me with a source, please.



Subject: WTB: Apache Junction Jasper and Zebra Jasper


We just attended a 'Rendevous' here in Colville and saw some
cabbed Apache Junction Jasper that was very nice indeed. He
said it came from Deming, New Mexico. Does anyone know of a
source for this material? It looks like it would make great

He also had "Zebra Jasper", which was of a quartz material
with black stripes that were bordered with a solid wavey
white band. We would also like to find some of that material.

Love reading the list, and do so appreciate your hard work.

Thank you,

Keith and Ann Berger
Round Rocks Etc., 765 E. 1st Ave., Colville, WA 99114
Check our site for GREAT hand made marbles

Subject: FS: Sphere Machines

We manufacture 4 sizes of sphere machines: A marble
maker/refinisher, one that makes up to a 3 inch sphere. one
that makes up to a 5 inch sphere and one that makes up to a
7 inch sphere.

Please contact me at or by phone at
303 936 6600.

Joe Adams
2903 South Meade Street
Denver Colo. 80236

Subject: FS: Yellow Cat Petrified Redwood

Hi Friends
In issue #225 Vi Jones asks if anyone has Yellow Cat redwood
for sale. Please let her know that I own "The Mineral Adit
Rock Shop, 2824 W. Colorado Ave, Colorado Springs, CO 80904.
Ph 719-475-1557. Email " and that I have
a nice selection of the Kladder collection of Yellow Cat
redwood for sale in the shop. It is extremely rare and comes
from a small area near Moab, Ut.


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