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. 224 - Thurs 8/5/99
2. NEW: Rainbow Obsidian Structure and Colors
3. NEW: Chrome Diopside Prices and Workability
4. NEW: Cabbing with S/C Slurry on Hardwood Disks
5. NEW: Star Sapphires
6. NEW: Schools for Learning Lapidary Arts
7. RE: Does Alunite Need to be Stabilized?
8. RE: Does Alunite Need to be Stabilized?
9. RE: Does Alunite Need to be Stabilized
10. RE: Does Alunite Need to be Stabilized?
11. RE: Does Alunite Need to be Stabilized?
12. RE: Parts for 6" Sears and Roebuck Gem Maker
13. RE: Parts for 6" Sears and Roebuck Gem Maker
14. RE: Parts for 6" Sears and Roebuck Gem Maker
15. RE: Parts for 6" Sears and Roebuck Gem Maker
16. RE: WAD or Romanechite
17. RE: Looking for Book(s) on Agates
18. RE: Looking for Book(s) on Agates
19. BIO: Peter Plantec
20. FS: Slab Saw


Subject: LapDigest News for Issue No. 224 - Thurs 8/5/99

This issue is getting so fat that I am sending it several
days earlier than planned!

Just heard that there are several slots open for the next
SFMS Wildacres Workshop on August 23-29. These are:
Gem Identification, 1 opening; Raku Pottery, 1; Beginning
Silver, 3; Adv Silver(Repair), 4; Advanced Wirecraft, 3.
Anyone interested should call Ron & Anna Denton,
(706)569-1219 to reserve a spot, then forward their
application and full fee immediately. Cost is $225 for the
week, I believe, which includes room, board, and instruction
- but not materials.

Hey, guys -- take care of yourselves and hug those you love
and - have fun!!!


Subject: NEW: Rainbow Obsidian Structure and Colors

I bought some chunks of rainbow obsidian rough at the show
at Franklin. I will describe one piece (but they all have
the same characteristics.). It is almost a cube in shape.
One side, which I will call the 'top', is covered with a
grey matte surface, except for a couple of small conchoidal
fractures, which are shiny black in color (typical obsidian
fracture structure). The opposite side, which I call the
bottom, has the same appearance.

The other four sides, between the top and the bottom, all
are striated with narrow grooves which follow all around
the cube and match up at each corner. (I was told to cut
parallel to these grooves to get the rainbow effect.) The
grooves vary in width; let's call where the grooves meet:
'lines', as that is what they are. These four sides all
have the same gray matte color as on the top and bottom.

Possibly, the lines and grooves could have come from some
weathering process and might indicate that there are layers
in the obsidian which differ in some characteristic such as
hardness. This would fit with the concept that the rainbow
colors each came from a different layer.

I had not known nor heard that obsidian changed
characteristics from top to bottom, as it solidified. I had
thought that it was a fairly homogeneous material.

I have not been able to find an explanation of the cause
of the colors in rainbow obsidian, nor anything else about
it's structure. If anyone knows about it's structure and
the reason for the colors, and why there are grooves aroung
the rough cube, I would appreciate learning it. Also any
references to rainbow obsidian (on any topic) would be


Subject: NEW: Chrome Diopside Prices and Workability

Hello from Istanbul,

I need information on chrome diopside prices.

Also if you can, tell me know how good is this stone for
carving or cabbing?

Kind regards,

Oya B.

Subject: NEW: Cabbing with S/C Slurry on Hardwood Disks


Can you give me any advice on using grooved hardwood discs
and s/c grit and water as a slurry to smooth and polish
cabochons? I read in a book that some cutters believe it
gives a much smoother polish than sandpaper. I tried using
canvas with a hard rubber backing but it seems to leave
pits in the stone.

Thanks for any help..

Chris Adam

Subject: NEW: Star Sapphires

A star sapphire shows a six-pointed (or rarely, twelve-
pointed) star-shaped image when viewed under a point light
source. There are also other star-reflecting minerals, all
of which show stars for the same reason: there are thousands
of tiny needle-shaped crystals within the gem. Star
sapphires contain microscopically thin needles of the
mineral rutile.

The crystals are oriented along the molecular axes of the
sapphire crystal, which has six-way symmetry. Light is
reflected by the shiny rutile crystals into the six-pointed

Sapphires are crystals of aluminum oxide, also known as
corundum. Corundum is the second hardest mineral, after
diamond. Rubies are also corundum crystals.


Subject: NEW: Schools for Learning Lapidary Arts

Dear Hale,

Do you have any suggestions for schools where I may learn
to be a Lapidary? Anywhere in the country will do but,
obviously, South Florida would be best.


Al Raskin
19444 Cedar Glen Drive
Boca Raton, Fl 33434

Subject: RE: Does Alunite Need to be Stabilized?

Alunite can be soft to hard. Most of the better material
does not need to be stabilized. The pieces that have yellow
in them are usually harder than the white. It will take a
good polish except for the chalky stuff. It polishes best
for us with tin oxide.

It can also be colored like turquoise if you have a mind to.

Micki Bleily
Bleilys Gems

Subject: RE: Does Alunite Need to be Stabilized?

Hi Hale,

<<Walt: I couldn't find Alunite in the first four books I
searched, and don't think I have ever heard of it or seen
it for sale. Tell me about it, please! hale>>

Found it in the 1995 Glossary of Mineral Species page 6
formula: K2Al6(SO4)4(OH)12
Trigonal (Hexagonal) system, Alunite group

Also found it in A Field Guide to Rocks & Minerals by
Fredrick Pough, page 177.

Is supposed to be white, light gray or flesh red, has
hardness of 3-1/2 to 4; S.G.: 2.6 to 2.9

A mountain of the stuff was found at Marysvale, UT
it goes on a little, but I don't think you would want to
use it in rings.

That’s all I can add, hope it helps.


Subject: RE: Does Alunite Need to be Stabilized

Peterson Field Guides "Rocks and Minerals" says it is basic
hydrous sulfate of aluminum and potassium with a hardness
3-1/2 to 4, white, light gray, or flesh-red; cleavage fair
basal and poor rhombohedral. Brittle; translucent to
transparent, sometimes fluorescent orange in UV light.
Closely resembles limestone and dolomite.

"A great mountain of alunite is to be found at Marysvale,
Utah, and several attempts have been made to work it
commercially, both by the exploitation of the potash as a
fertilizer and the balance as an ore of aluminum. ...

Although uninteresting from the specimen standpoint, it is
potentially valuable as a raw material."

All you wanted to know and more.

Robin Pascal

Subject: RE: Does Alunite Need to be Stabilized?

Alunite is a potassium aluminum sulfate, K-Al3-(SO4)2-(OH)6
(sorry, can't do subscripts here). Also called alumstone.
They use it mostly to produce alum. There are some (now not
active) mines near Marysvale, UT that I have visited a time
or two. The ore can be processed to recover both potassium
and alum, and they started to develop the Marysvale mines
during WWII; more to get the potash for gunpowder than for
the aluminum, as I remember. But they got into a big hassle
with the State government vs private parties etc. about just
where to build the plant where it was going to be processed,
and very little came of it before the end of the war. It's
mostly massive or disseminated, but the stuff I have from
the "good" mine is somewhat crystalline and rather

It is rather soft, about 4.

Walt: does it need to be stabilized? I don't really know,
because I never heard, before, of anyone with any interest
in working it. (Or of how it would be worked, or stabilized,
if they do). Mine, at least, is pretty blah as far as color
is concerned (although perhaps yours is different??)

Maybe someone else can throw more light on the subject.


Subject: RE: Does Alunite Need to be Stabilized?

Alunite is sulfate of potassium and aluminum. Hardness:
3.5 - 4.0. Sp G: 2.6 I have the chemical composition if
anyone wants it. Alunite, also known as Alumstone, is found
in Nevada, Utah and Colorado. It is a reddish pink with gray
areas and has a waxy feel. The material I have used would
not need to be stabilized. I do not think it would absorb
stabilizer easily.

The suggestion about using a stocking in polishing gypsum
sounds interesting and viable. My alunite is in a sphere
form and polishing was not easy due to its softness.

Mike Eggleton

Subject: RE: Parts for 6" Sears and Roebuck Gem Maker

Before you twist the wires to pull the covering tight, cut
a "vee" nick in the rim at the point where you are going to
do the twist. After twisting the wires, bend them down
into the vee nick (cut).

This makes it a lot safer. Don't forget the safety rule -
turn the switch off if you're going to put fingers down to
find something that has come off.

Mike Eggleton

Subject: RE: Parts for 6" Sears and Roebuck Gem Maker

If you need to tie a leather buff to a disk that has a slot
or groove, you may use some heavier weight nylon fishing
line. This will tie it securely but will not skin your
knuckles if you get too close.

The other method is to use some kind of perforated holes in
the outer rim (circumference) of the leather pad and use
the nylon line like a shoe string and lace the leather pad
as tight as possible with the nylon line passing over the
back of the aluminum disk.

Subject: RE: Parts for 6" Sears and Roebuck Gem Maker

Hi Hale, Hi Richard,

If I didn't throw it out in this past weekend's massive
workshop cleanup blitz, I should still have a picture of
the Star Diamond 6" Gem-Maker, the one which I believe is
identical to what was sold under the Sears brand. If you
can't find a picture close by, email me off list.

Freelance writing. Feature stories, technical ad copy,
clear manuals, bid documents, simple english, videos,
speeches. Email for publication and client list.

Subject: RE: Parts for 6" Sears and Roebuck Gem Maker

When I was a kid (back in the 60's), I think Sears sold B+I
(Burlington Industries?) gem makers made in Burlington,WI.
They were three legged vertical shaft machines that required
switching the blades/wheels and had a small coolant tank and
saw vise.

I had an 8" B+I, but there was also a 6" model. Not very
handy because you used the side of the grinding wheel. When
changing wheels, you never lined it up the same so the wheel
developed a bounce due to uneven wear.

I don't know what happed to B+I.


Subject: RE: WAD or Romanechite

Lee Corey,

You happened on a favorite subject of mine lately. There is
a dealer named Dave Hignett who has some rough for sale. I
bought some last month for $20 a pound. This particular
material comes out of a mine in Chihuahua, (like the dog)
Mexico. I think you will be very happy with this material.
It's very hard, coal black, with silver agate like lines
through it. Here's his business card:

Dave T. Hignett
The Agate Gallery
1408 N. Lowell Street
Santa Ana, California 92706
(714) 558-6003

Interesting, I've never heard those names used for manganese
ores before. I'll have to add them to my list along with
"Crown of Silver Agate" and "Corona Del Plata Agate."

By the way, there are at least a couple of places east of
Los Angeles in the Mojave Desert where you can dig
psilomelane. It's one of those things on my "to do" list
one day.

Terry Vasseur

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

I have one that is published by the British Museum (Natural
History), Cromwell Road, London, SW7 5BW. The book is simply
called Agates and its ISBN number is 0565011006. It gives
agate locations throughout Britain with some excellent
photos. The best (of course) coming from Scotland.

Alec fae Scotland

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

Tim (?) Cross was selling a book on the Agates of Northern
Mexico. By the way, he lives in Austin. I don't have the
book handy, but if no one has any details, I can dig it up.

Subject: BIO: Peter Plantec

Hi folks.

I'm Peter Plantec, a software developer with a passion for
opals and a love of Amber and fossils. I don't cut fossils
as I think it's just the wrong thing to do. I love to cut
and polish amber to reveal the inclusions. But, I just find
quality opal something that endlessly fascinates me. I'm
learning to cut and shape fire agate as well. It's quite
challenging for a newbie like me. I also want to learn all
I can about opals.

My wife suggested I buy some opal from E-bay because you
can see photos, but I'm not convinced. I'd love to hear
from other opal lovers about good sources that don't kill
you with their prices.

Peter Plantec
Creative Director
Virtual Personalities, Inc.
Beverly Hills, CA

"We can create pretty fair artificial's
artificial wonder that stops us cold."

Subject: FS: Slab Saw

I have a 24" Covington saw for sale. It is has large
lengthwise capacity and is built like a Sherman tank. The
blade shows very little use.
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