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

1. LapDigest News for Issue No. 81 - Fri 11/7/97
2. NEW: Cutting Chatoyant Jade
3. RE: Apache Tears
4. RE: Apache Tears
5. RE: Ultrasonic Drilling
6. FS: Lapidary Books


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<MSG1>

Subject: LapDigest News for Issue No. 81 - Fri 11/7/97

The Index to the Archives has been updated through Issue 80,
and is in the Archives as INDEX.TXT.

If you do channel work, would you send me a note and tell me
about it?

Have a great weekend!

hale
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Subject: NEW: Cutting Chatoyant Jade


I want to make some cabs and a pendant out of a chatoyant
piece of green nephrite jade. The rough is a core that is 4
inches long by 1-3/4 inches in diameter. There is a chatoyant
band that is 1 inch thick that runs across the diameter of
the core and through the length of the core.

Is there an optimum angle to cut the jade in relation to the
chatoyance to maintain the maximum chatoyant effect?

Thanks,

David Clayton
drc@ccnet.com

non-commercial republish permission granted
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Subject: RE: Apache Tears


Peter Rowe wrote:

<<What happens with apache tears is that with weathering and
aging, some of the glass starts to actually crystalize out as
it's component minerals. This occurs forming vein and seam
like structures, forming a honeycombed sort of thing that can
then break apart along those devitrified seams. That's what
forms the chunks that, after stream tumbling and erosion,
become apache tears.>>

This is the basic process but, having collected Apache tears
"in place," I would say that stream tumbling isn't involved
in their formation. Older obsidian flows absorb water along
cracks, forming the honeycomb effect Peter refers to. (This
is part of an alteration process from obsidian to a partially
altered material known as "pitch stone"). Sometimes fresh
glassy obsidian "cores" (Apache tears) are left inside this
series of cracks. Another process is also involved.
Moisture trapped inside the pitchstone swells up, forming a
frothy pumice-like form of glass known as perlite along the
cracks. (Pough says heat is involved, which makes sense).
While Apache tears eventually erode away and may be found in
streams, perfectly-formed rounded glass pebbles are found
inside the perlite. (See Figure 150, page 504, Vol. 1,
"Gemstones of North America," Sinkankas.


Rick Martin
R-Orion@postoffice.worldnet.att.net

non-commercial republish permission granted
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Subject: RE: Apache Tears


Hi-

A posting in #80 implied that the round, smooth shape of
Apache tears is the result of stream polishing; this is not
the case, they look just the same while still in bedrock.

Dick's theory on Apache tear formation:

Some surprising things can make up a solution under pressure.
Sub-surface molten rocks have water and assorted gasses in
solution, as long as they remain tightly confined. When
pressure is released, either by actually reaching the surface
or near surface, or by cracks venting to the air, these gasses
escape quickly- imagine the apparent stability of a shaken
bottle of coke, until you jerk off the cap. Sometimes, these
molten rocks can cool so fast, that the rock can contain the
water within the solid structure and remain relatively stable
at atmospheric conditions. Apache tears are always found
encased in concentric layers of pearlite- kind of a frothy
volcanic glass, presumably formed by escaping gas/steam from
the molten obsidian. I figure that all the volatiles didn't
get a chance to escape before the hardening pearlite sealed
off the system, leaving scattered round nuggets of regular
obsidian (with water in solid solution): Apache tears. As a
test, stick one in a high temperature kiln. When the glass
reaches softness such that the gasses trying to escape can
overcome the viscosity, the whole thing will pop into
expanded pearlite about the size of a softball, with texture
like crispy styrofoam.

Make sense?
Dick
dale@bo.net
non-commercial republish OK
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<MSG5>

Subject: RE: Ultrasonic Drilling

Hale,
Have enjoyed your lapidary digest and your effort. I am a 30
year lapidary guy. I make mainly hearts and crosses for a
personal ministry, and also baroque belt buckles out of
mainly Montana Moss agate. I have a 90 section piece of
eastern Montana to hunt, thanks to a rancher friend.

To set a loop in my pieces, I aquired an ultra-sonic drill
from a friend about 15 years ago for about $500. It was made
by Geo-sonics of New London Ia. 52645. However, about 3 years
ago I had trouble making the drill operate so I called these
people to get help. They told me Geo-sonics had been bought
and closed out of business. They had a few parts in a box
which was not very helpful. They told me that to replace my
drill would cost about $7000 or more. They intimated that no
one was making a hobby drill such as mine anymore.

I eventually got mine going by just tinkering around with it.
It works great, drills a 3/8" hole in minute or so, using an
oscillating wire mounted in a cone with a grit slurry flowing
down the wire. It uses an ultrasonic generator to set up the
vibration.

This all probably doesn't help the call for help, unless he
can find someone with a used Geo-sonic who wants to sell.
Remember that no parts are available, tho some guy into
electronics may be able to rig up or fix one of these things.
Whether there is another firm making these machines old or
new I do not know. I suspect not.

Bill Carrothers
nipntuck@concentric.net

Non-commercial republish permission granted.
-------------------------------------------------------------
(Ed. Note: Lapidary Journal Index shows only one article on
this subject; it is ULTRASONIC DRILLING 75:04:355. hale)
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Subject: FS: Lapidary Books


1) GEM CUTTING - Sinkankas, $67.95 Excellent for the beginner
or experienced gem cutting hobbyist.

2) THE ART OF GEM CUTTING - Dake,$4.50 Show how to buy rough.

3) ADVANCED CABOCHON CUTTING - Jack Cox, $4.00 Master special
shaped cabochon cutting.

4) CABOCHON CUTTING- Cox, $4.00 From doping to setting the
stone.

5) INTRODUCTION TO LAPIDARY- Kraus, $19.95 What equipment to
purchase for different fields in lapidary.

6) PRO-AM GEMCUTTING GUIDE - Ridge, $1.50 How to take care of
equipment.

7) HOW TO USE DIAMOND ABRASIVES - Riggie, $4.00 How to use &
take care of equipment (very good book for the price)

8) MASTER GEM CUTTING TIPS - Wycoff $14.95 Covering faceting,
cabbing, carving, gemology & related topics.

THE AUDUBON SOCIETY BOOKS

9) FIELD GUIDE TO NORTH AMERICAN ROCKS & MINERALS -
Chesterman, $19.00

10) FIELD GUIDE TO NORTH AMERICAN FOSSILS -
Thompson $19.00

11) FIELD GUIDE TO FAMILIAR ROCKS & MINERALS -
Chesterman $ 19.00

BOOKS ON TUMBLING

12) PRO-AM TUMBLE GRIND & POLISH GUIDE-
A.V. Ridge, $1.95 beginners guide.

13) GEM TUMBLING-
The Victors, $3.50 Tumbling from beginning to end.

14) HOW TO TUMBLE, POLISH GEMSTONES & MAKE TUMBLED JEWELRY-
Wexler, $4.00 Step-by-step instructions for tumbling rough
stones into sparkling jewels.

15) LORTONE TUMBLING BOOK- Lortone, $1.50 How to, for how
long & what amount of grits & polish to use. (this book
comes with all LORTONE tumblers, which we also carry.)

We also carry books on CARVING, GEOLOGY, PALEONTOLOGY,
FLUORESCENCE, MINERALOGY, FIELD COLLECTING, GHOST TOWNS,
TREASURE HUNTING, PROSPECTING, GEMSTONES, BUYING SELLING &
APPRAISING,BEADING, ENAMELING, FIMO & CLAY, STAINED GLASS,
STONESETTING, PLATING & REFINNING, ENGRAVING, CASTING,
INDIAN JEWELRY MAKING, JEWELRY MAKING, and MAPS (atlas &
gazetteer for various states) We also have how to videos
available.

DO NOT SEND CREDIT CARD INFORMATION OVER THE INTERNET!
Prices subject to change. You may E-MAIL me for your other
needs and or purchases.

PHONE: 1(800)820-3612

You may send check or we can send COD. All books are not
always in stock, so it's best to get together before issuing
a check.

Thanks BETTY and RUSS
jaderockshop@webtv.net
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