Web Site: http://www.lapidarydigest.com
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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 191 - Sat 1/2/99
2. NEW: Cabbing Emeralds
3. NEW: Questions about an Opalized Clam
4. RE: Orienting Star Garnets
5. RE: Variscite
6. RE: Variscite
7. RE: Variscite
8. RE: Variscite
9. RE: Which Oil to Use in a Slab Saw?
10. RE: Which Oil to Use in a Slab Saw?
11. RE: Which Oil to Use in a Slab Saw?
12. RE: Which Oil to Use in a Slab Saw?
13. RE: Which Oil to Use in a Slab Saw?
14. NEW: Which Oil to Use in a Slab Saw?
15. RE: Which Oil to Use in a Slab Saw?
16. RE: Which Oil to Use in a Slab Saw?
17. RE: Which Oil to Use in a Slab Saw?
18. RE: Which Oil to Use in a Slab Saw?
19. RE: Which Oil to Use in a Slab Saw?
20. RE: Which Oil to Use in a Slab Saw?
21. RE: Which Oil to Use in a Slab Saw?


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<MSG1>

Subject: LapDigest News for Issue No. 191 - Sat 1/2/99


Happy day after New Year's Day!!

As I mentioned before, I am putting together a list of
member's links, and would appreciate it if you would send
me your URLs, your first and last names and a short
sentence or two describing your website. Following is a
example showing what I would like the list to look like,
and what the description should be like:


-----Member's Web Pages-----

Susan Herrmann http://pages.sssnet.com/7genex7/

This site is dedicated to promoting knowledge and
awareness of Scythian art and related ancient arts
and history .

Jeanne Ridolfi www.rockpeddler.com

Site has discount lapidary equipment & supplies;
also faceting and cabbing rough, and online catalog.

Greg Fisher www.gemsources.com

A wholesale searchable database of gemstones
restricted to members of the trade, password
protected. Apply for passwords on line.

Kreigh Tomaszewski http://www.concentric.net/~Tomaszew

The Tomaszewski Family Public Web pages with home
pages for each member, details on our hobbies, including
the family Intranet, some links we've found useful, foster
parenting, and our family genealogy.

--------------------------------

These will give you an idea of what we need. Please send
your information as soon as you can.

Hey guys ... remember to tell your loved ones how you feel
about them, remember to give them hugs - especially the
children - and, above all, HAVE FUN TOGETHER!!


hale
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<MSG2>

Subject: NEW: Cabbing Emeralds


One of my planned projects for the new year is to finally
cab some small emeralds that I have. They are no more than
a few millimeters in any direction, but they look nice,
decent color, and are not too included. All I've ever heard
is how brittle they are (coming from a jewelry background),
so I'd really like some advice. Do I need to orient the
crystals somehow? Is there a preferred method of dopping?
Is there anything I should or shouldn't do?

Normally I tend to just dive right into a project and figure
it out as I go, but emeralds are one of my favorites and I'd
like to end up with the same number of stones as when I
started.

Thanks for all your help!

~kara
<karac@email.his.ucsf.edu>
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<MSG3>

Subject: NEW: Questions about an Opalized Clam

(for Tim Vogle)

Hi Tim -

Just read your post re the 6" flat laps, and see you deal
in whole opal clams.

I have a question about these. Recently I got a clam about
the diameter of a silver dollar by way of trade. Outside,
it's a uniform frosted milky white to tan colour. Away from
the hinge, where the shells join at the front, some small
chips have broken off, revealing glassy opal with a few
areas of green and blue pinfire. No fire is visible looking
at the exterior rough shell.

It looks quite attractive as a clam. But yet I'm an opal
fiend too, and in my quest for cuttable stones am sorely
tempted to cut the clam into two halves say along the
juncture where the shells meet.

My question is, do these clams normally contain a treasure
trove of cuttable opal? Or do they ever yield cuttable opal
at all? Or sometimes, or only rarely...or? or?

If you were in my shoes would _you_ cut it or leave well
enough alone? And why?

Cheers & thanks

Hans Durstling
sinico@nbnet.nb.ca
Moncton, Canada
-----------------------------------------------------------
(Note: ANYONE on the list can chime in with an answer! hale)
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<MSG4>

Subject: RE: Orienting Star Garnets


One question on tumbling before orienting garnet stars. A
retired geologist friend of mine says that garnets, because
of their metamorphic origin, have a lot of internal stresses
built into them and that you will crack a lot of stones in
the tumbling process that would have been cutable otherwise.

What about that???


Rose McArthur
obmcarthur@clearwater.net
-----------------------------------------------------------
This raises another question: If you have stones with high
internal stresses, can you heat treat them to reduce or
eliminate the stresses, as you can with metal, without
destroying the stones? If so, how high a temperature must
you go to and for how long? Flintknappers regularly heat
treat their stones, taking them to high temperatures for a
long soak. They say - and I believe them - that this makes
their stones flake better. But to eliminate internal
stresses? hale
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<MSG5>

Subject: RE: Variscite

Hale -

I've been cutting it up for intarsia also, which is why I
am asking if I am wasting valuable rough just to have some
green in my pieces. I have other greens I can use if so.

My impressions on the pieces I've sawn and used for
intarsia and also the two stones I cabbed : Sawing and
grinding wise, very much like turquoise, same with
polishing, matter of fact for the massive type other than
it's a pretty green handles the exact same. The more
translucent deep green stuff cuts faster and seems softer
so would not make a good ring stone. The deep green looks
fantastic against red jasper with lapis by the way.

Oh and a good use for a faceting machine that does not
belong on Jerry's list ;) You can make very precise and
detailed intarsia on a faceting machine.

Ken
kwetz@home.com
-----------------------------------------------------------
Ken: That is exactly the reason I bought a used but good
faceting machine. Yes, I use a faceting machine, but not to
make facets (altho a list member did accuse me once of
hating faceting!!) It is a great adjunct to intarsia!! hale
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<MSG6>

Subject: RE: Variscite


Hi Hale and gang,

Golly, all of the Variscite that I have is in micromounts,
and they are just lovely the way they are!! The biggest
might be 1mm or so. Doubt that I would cut any of them.

Mine come from Indian Mt., AL, Utah, and near Girard, GA.
Might have more locations, but Utah and Nevada seem to be
the most plentiful. The Audubon book does state that it has
been used as a gemstone.

Hope everyone has a safe and Happy New Year.

Earl
ewenglish@blueridge.net
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<MSG7>

Subject: RE: Variscite


Ken,

Variscite is almost identical in its properties and in
value to turquoise, the most sought after is the translucent
green, especially the older material with yellow banding in
it (Wardite). Really good translucent Variscite /Wardite is
rare and more valuable than the rest. Kelly Green opaque
material is next in value, then the turquoise colored
material. The turquoise colored material can be found with
a black matrix making it almost identical in appearance to
turquoise.


Gil Shea
legal@mtaonline.net
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<MSG8>

Subject: RE: Variscite


Just a few notes on Variscite. Joseph E. Pough in his book,
"Turquoise", mentions Variscite as sometimes being mistaken
for turquoise. The classic illustration of it that you see
in books on semi-precious stones shows a slab with circular
patterns in it--outlined in an olive mineral, if I remember
right. Came from Fairfield, Utah.

Occurs also in Nevada, Australia, and Spain. I know what
you mean about that beautiful emerald green type. It really
grabs you. I once fell in love with a slab "from an old
collection" and bought it for a pretty penny, only to
discover that it was composed of little blobs with
imperfections in between. Sigh. Well, it will still make
a lot of nice ring cabs.

Sinkankas, in his "Gem Cutting, A Lapidary's Manual" says
that the dark material is harder and takes a better polish
than the softer, more porous light colors. Because of
variations in the hardness it is difficult to get a well
shaped stone and care has to be taken on the sanding. He
recommends smoothing with diamond paste on leather or wood
to keep from undercutting, and finishing on leather with
diamond, Linde A, or cerium oxide or tin oxide.

My cousin has a nice necklace of Variscite made in the 40s.
Would like to know if it went through a period of
popularity then.

Rose McArthur
obmcarthur@clearwater.net
-----------------------------------------------------------
Random information on Variscite:

1. Variscite is found in Utah, USA; Germany; Australia and
Brazil.

2. It was discovered in 1837, when Breithaupt described
material from Voigtland in Germany. The mineral name alludes
to Variscia, the ancient name for the Voigtland.

3. Variscite is in the Variscite Group. Other minerals in
this group include: Mansfieldite, Scorodite, and Strengite.

hale
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<MSG9>

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


In a message, you write:

<< Is there any valid reason NOT to use vegetable oils in
our cutting saws? I figured that I might have to clean it
a little more often, but other than that?>>

Vegetable oil will go rancid and will not smell much better,
if any, than the more accepted saw oils. As it heats, it
thickens and forms a varnish coating. Ever notice an old
frying pan, the dark brown, black coating that most cooks
leave on because it is tuff and will not stick as bad as the
metal. I expect a like buildup will happen over time on the
blade.

The two light machine oils that work the best, are
within budget for their price, and available, are Shell's
Pella-a, and Texico's Almag. Both have a minimum of bad
things listed on the label. Both are designed for
machining, cooling and lubricating. Both will stink a
little. I have tried using a 1/4 cup of Pinesol in new oil
and that seems to help the smell problem a bit.

Don at Campbell Gemstones
<Campgems@aol.com>
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<MSG10>

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


FWIW

I've never used a vegetable oil in a saw, but I'd think it
would be to volatile & gummy. I once used canola oil to
store clean steel shot in a closed tumbler for the summer.
When the tumbler was opened about 2-3 months later, the oil
had mostly congealed & the was quite a mess.

At our lapidary club, we use Texaco's ALMAG in our 5 saws
(10-24"). It works fine, if the saw is left idle for a day
or so, the swarf settles to the bottom of the pan & could
be removed without much difficulty (notice, I didn't say
anything about a mess (bg)).

ALMAG is manufactured to be used in the metal fabrication
industry as a coolant for machining items made from aluminum
or magnesium. It works fine for rocks as well. We've used it
for over 10 years. It cleans up with soap (Dawn dish
detergent) & water. We get the ALMAG in 5 gal cans from our
local Texaco bulk plant.

Dave
gemstonesetc@gci-net.com
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Subject: RE: Which Oil to Use in a Slab Saw?


John,
Don't do it! Vegetable oil works well for cutting - but if
you let it sit too long between uses it will coat the inside
of your saw with an impenetrable plastic-like layer of
hardened goop. I recently got a tremendous deal on a used
10" trim saw - the only catch being that I have to remove a
layer of dried soybean oil/rock dust from it before I can
use it. It's a daunting task. :-)

I recommend that you use either a soluble oil (can be mixed
with water) or Texaco's Al-Mag oil. The Al-Mag can be rough
on your hands, so wear gloves if you use it. It allows a
superior, friction-free cut. I've never seen a blade warp
while running with Al-Mag (and I can't say the same for
soluble oil).

Pete Steiner
Buffalo, NY
troubadr@buffalo.edu
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Subject: RE: Which Oil to Use in a Slab Saw?


I think that all vegetable oils tend to dry to a film, given
time. The heat would doubtless accelerate the process. But
the major reason not to use it would be its lack of
stability over time: when the oil goes rancid it will smell
really bad. I use USP mineral oil, which isn't much more
expensive, lasts forever if it's filtered periodically, and
doesn't dry or go rancid. But I have to say I've never
actually filled my saw up with Wesson oil- if you do this,
let us know how it works out.

Andrew Werby
drewid@LanMinds.Com
Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com
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Subject: RE: Which Oil to Use in a Slab Saw?


There has been a long thread running on the Orchid List, a
jewelry makers list, regarding a person who now owns a slab
saw which was filled with soy bean oil. The oil has formed
an extremely hard surface on all of the saw's interior. One
problem may have been in having some residual petroleum
based oil which mixed with the soy oil. However, given the
serious problem the saw owner is having cleaning the saw for
use, I would be very hesitant to fill a saw with vegetable
oil.

An alternative suggestion is to use mineral oil. Doug
Duffy, director of the lapidary lab at the Arizona Museum
of Mining and Minerals has about twelve saws of all sizes.
He has been using Duoprime Oil which is a white mineral oil
with vitamin E added as a stabilizer. Doug has had the oil
in use about two years and has found that the odor is much
less than Almag Oil and the mineral oil does not seem to
mist as much. He has purchased the oil from Western States
Petroleum, Inc. The oil is approved by the USDA for contact
with meat and poultry, and it is approved as kosher!

John McLaughlin
jmclaughlin@supreme.sp.state.az.us
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Subject: NEW: Which Oil to Use in a Slab Saw?


It will go rancid and stink. That's enough reason not to
use it.


Tim Fisher
Ore-Rock-On and Pacific Fishery Biologists WWW Sites
Tim@OreRockOn.com
WWW: http://OreRockOn.com
See naked fish and rocks!
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Subject: RE: Which Oil to Use in a Slab Saw?


Hi Folks -

In brief, don't do it.

I once ran out of oil and used a combination of Mazola and
olive oil. It cut well enough but the mix then dried and
hardend like paint, coated everything! inside the saw. Took
me forever to scrape the resulting gunk off. Some of it is
still there, and that was eight years ago that I did it.

Cheers,
Hans Durstling
sinico@nbnet.nb.ca
Moncton, Canada
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Subject: RE: Which Oil to Use in a Slab Saw?


Happy new year Hale:

Snowing and cold here. Supposed to get down to single
digits tonight.

There used to be an urban legend about the use of vegetable
oils in slab saws. They said the oil would turn rancid and
develop a strong odor after repeated heating. Probably a
myth that kept us using commercial oils. I still stick
with the commercial oils. Just don't use transformer oils.
I know those have serious affects.

Steve Ramsdell
sramsdel@prairienet.org
-----------------------------------------------------------
Steve: we had a thread a while back about the danger of PCB
in transformer oils. During that time, I talked to people in
two power utilities and both confirmed that the PCB-laden
oil in almost all transformers have been long replaced. One,
in charge of this area, said that they may have one PCB
transformer left on their system, and that they would never
sell the PCB-laden oil, but would send it to a proper
disposal area -- I think they incinerate the old oil. Thus,
I would not be adverse to using transformer oil obtained
from a major utility! Particularly if they gave you a
certificate saying that it was free of PCBs. hale
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<MSG17>

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


Does woodworking experience count? <g>. I can tell you that
in general, vegetable oils are "drying oils", whereas
mineral oils are not. Vegetable oils will eventually harden,
first into gum, then varnish. Also, Hale is right about heat
accelerating the process.

All that means, of course, is that cleaning more often is
necessary, as you say. As far as conducting the heat away
and providing lubrication, I expect it would work fine.

Al
albalmer@worldnet.att.net
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<MSG18>

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


Someone wrote me a post a while back stating that they
tried the vegetable oil and it really made a mess of their
saw. Since then I've been introduced to coconut oil -- its
solid below a certain temperature but warms up quickly and
I'm told it doesn't congeal. Whether it really does or not
remains to be seen -- I have left some open to the air for
a few months to test it. By the way it's odorless - doesn't
smell like coconuts at all.


Susan Herrmann
7genex7@sssnet.com
-----------------------------------------------------------
Susan: If what Al Balmer said holds true for coconut oil,
(and it is a vegetable oil!) you may wish to reevaluate
using it as a saw oil. hale
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<MSG19>

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


When I read the cutting oils letter in LD#190, I thought I
would comment on it as soon as I got a few minutes. In the
meantime I read the article on cutting Saginites in the
Febuary 99 issue of Rock and Gem, which covers cutting oils
quite well. I will add that vegetable oil does not have the
cooling properties and wear resistance required of diamond
saw blades, (according to the article there is a special
food oil that does work). I have used Almag for more years
than I care to remember and it works beautifully, it rinses
easily and washes off with any mild dish detergent. But
most important of all it protects your expensive diamond
blades from heat and wear. I have never encountered any
unhealthful side effects as noted in the article as I use
a number of precautions such as rubber gloves and vents
and of course when cutting malachite, a respirator. Also
the use of a dry sump on your saw will keep the oil clean
and give it a longer life. Hillquist Inc. of Fall City
Washington has a good inexpensive and compact dry sump,
(coolant recovery tank) that I use and works well, and I
am fabricating one for my 24" saw.

Keep on cutting
The Geode Man
Ernie Ogren
Thegeodman@aol.com
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<MSG20>

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

Do not use vegetable oil, soybean oil, etc. for any reason.

I had the experience of using it several years ago. When I
started cutting rocks in my ten inch Lortone slab saw
everything seemed to be going very well. No smell. Easy to
clean. But then I stopped using the saw for about six
months. When I went back to try to cut another stone I
found that the saw was completely covered with a gummy
material which did not want to dissolve with any normal
thinners.

My solution to this gummy mess was to use four cans of oven
cleaner and a garden hose to get the gunk off of my saw.
I had to repaint, reoil etc.

I would never want to go through that again. DO NOT USE
VEGETABLE OILS AS A LUBRICANT IN SAWS.

Sincerely,
Dick Rathjen
rpc@flash.net
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<MSG21>

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


My experience with vegetable oil is that it gums up and
makes an awful mess. I'm not sure if the heat from cutting
actually gums it up, however, I do know that the oil
thickens after it has set in your saw's reservoir for a
period of time.

If you use a large saw, use Almag or Pella and keep your saw
in an open air or well ventilated area.

If you are just cutting small stuff, a large 10" commercial
tile saw is an amazing tool to have. It can also be used as a
carving tool on softer materials and all you use is water
to cut with.

Dee Purkeypile
dpurkey@swbell.net
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