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. 62 - Tues 9/23/97
2. NEW: Soapstone Carving Rough and Supplies
3. NEW: Lapidary Grinding Wheels
4. RE: Lapidary Grinding Wheels
5. NEW: How to Polish African Landscape Jasper
6. NEW: Labradorite and Peristerite
7. NEW: Tools for Polishing with Diamond
8. BIO: Jim Newman
9. RE: Refurbishing an Old Lapidary Machine #60
10. RE: BUDDSTONE #61


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<MSG1>
Subject: LapDigest News for Issue No. 62 - Tues 9/23/97

Garry Platt is an AMBER collector and author, and he now
has a Web site which focuses on AMBER... a very complete
site. If you want to see a well designed Web site, or if
you want to know almost anything about Amber (except how
to work it) and Amber's cousins, I recommend a visit to:
URL = http://www.gplatt.demon.co.uk/

I think it would help if we all signed our submissions
with our names and our e-mail addresses. Something from
"burp@net.com" just doesn't read as well as something
from "jim smith"!!

Have fun, be safe, smile!

hale
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<MSG2>
Subject: NEW: Soapstone Carving Rough and Supplies


Just getting into soapstone carving and as usual, I would
rather collect my own rough, as I do for cabbing (mostly).
Anyone know of a quarry that produces soapstone as a waste
product that can be visited by a gem and mineral club on a
field trip?

The area I am interested in is: Any of the following states
during the April to October season: All of New England, NY,
PA, NJ, DEL, Maryland, W.V. VA, Ohio, or NC. Then any
southern state in the winter from Florida across to Arizona
as long as it is low elevation (relatively warm).

Also, where can I buy fine-tooth rifflers and 2-point files
able to stand-up to pyrite/magnetite inclusions?

Thanks, Dave Millis, ROCKDOC@epix.net
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<MSG3>
Subject: NEW: Lapidary Grinding Wheels


Here is a two part question set:

1. Silicon Carbide lapidary grinding wheels are said to
be available in grit fineness beyond the usual 220, even
up to 600 grit. I would like to hear about such and,
especially, where they can be purchased.

2. Some Silicon Carbide grinding wheels do hard labor
and last for a very long time while others seem to get
"eaten up" in short order. Is this my imagination? I have
heard that there are differences in bonding agent integrity
with some being specifically "sacrificial" to prevent
loading and grit size reduction (wearing). Can this be
true? I never see any life span or work usage claims in
the catalogs... Rio Grande, for instance, says you can
have either of two sizes in either of two grits- and that's
it! If anyone knows the "inside" story, I would like to
learn a bit about this most mundane topic... and,
especially, where to purchase with a choice.


...gtb <gtbutts@infinet.com>

*---------------------*
* George Butts, KC8T
* Laurie Butts, N8CKI
*---------------------*
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(Ed. Note: I asked Peter Erdo of Graves Co., a member of
this list, to talk about the Silicon Carbide wheels which
are available today, and he sent this response. Thanks,
Peter ... hale)
---------------------------------------------------------


<MSG4>
Subject: RE: Lapidary Grinding Wheels


The finest grit that is commercially available for lapidary
use is a 320 grit. Beyond that the silicon carbide grain
becomes too powdery to make a good lapidary wheel, as well
as too expensive. Please note that I said lapidary wheel.
I am sure that there maybe other finer grit wheels but none
that are rated for grinding rocks.

There are two types of SC wheels available in both 100 and
220 grits. The 320 grit is not carried by the major
suppliers ( Graves included ) because sales do not warrant
it. A majority of work beyond 220 grit is handled by diamond
abrasives or SC belts. One type is the green wheel. It is
softer and more aggressive, wears away faster to prevent
loading. The other is the black type. A little harder, it
lasts longer but may not be as aggressive as the green. We
sell only black as the green is about 30% more expensive
and the differences in cutting speed are really most
important to the production houses. Even these folks are
almost all diamond now.

Silicon carbide is the dinosaur of lapidary. It does have
its place in lowering initial costs but in every other
respect, diamond is simply better, cleaner, faster, and
in the long run cheaper.

Peter Erdo
Graves Company

Non-Commercial Republish Permission Granted
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<MSG5>
Subject: NEW: How to Polish African Landscape Jasper


I recently tumbled a load of African landscape jasper. It
shaped beautifully -- no complaints there. But, I couldn't
get it to take a polish. I tried two types of tumblers --
rolling and vibrating -- and three types of polish. No
shine. I finally let it tumble in the vibrating tumbler
with Rapid Polish for about a week, then tumbled it for
another week dry with dry pellets. Finally, a shine! This
whole process took about a month, and I was getting really
aggravated. Has anyone had a similar experience? Is this
problem common to this type of jasper or to jasper in
general? Just curious and would appreciate feedback.

Thanks.

Jenna Ortolani
ortolani@airmail.net

Non-Commercial Republish Permission Granted
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<MSG6>
Subject: NEW: Labradorite and Peristerite


Hey, am I all wet? This is what I think I know about
labradorite and peristerite. Yes, labradorite is the
mineral, but spectrolite is the lapidary/gem name
regardless of origin. I just got some excellent material
(trading) from Saranac Lake, NY. The grain size is
relatively small, several inches max. It cuts nice.

As far as orientation goes: The critical step is orienting
the rough to make the slab. After the slab is cut it's too
late or too early, depending on your frame or reference.
The slab should never be cut so that maximum "fire" is
parallel to the slab surface; 10 or 20 degrees off is OK.
Then it is necessary to orient the cabbing template so
that the long axis of the ellipse will orient the stone up
or down (unless you are planning on mounting the stone
horizontally. Here's why. These stone are usually worn as
pendants or ear rings as they are a little soft for rings.
That means they hang vertically. Since most lighting is
overhead, flat slabs throw their "fire" down where you
won't see it! A correctly cut stone catches the light from
above and throws color up and out. Ellipsoidal cabs can
only show well in one vertical position; rotate the cab
180 degrees and the fire goes down and away. However, if
you are interested in displaying your cabs, you should
start all the way back to the rough stage where you slab
to get a different angle specific to the display case
lights and your intended cab orientation.

Had enough? - There's more.

The "fire" in labradorite or peristerite is caused by
twinning of two different feldspars. It's the same two
feldspars that produces the blue and related colors at some
angle. Then there is peristerite (note some USA books do not
list peristerite as a mineral; try a Canadian book as most
peristerite comes from Ontario) which has a second plane
of fire usually some shade of bronze. This is caused by a
second twinning. So there are at least three feldspars in
peristerite. All the same rules for cutting apply here;
ignore the bronze "fire"; cut as if it only had blue.

And the final point about cutting these stones: Make the
dome high. The more rounded the dome the better the fire
shows at more angles. Cabs over 22x30 should be cut from
slabs greater than 1/4 inch!

Hale, if you are going to use these for intarsia cut as if
it were for a display case.

Finally, here's a trick I learned about cutting feldspar
which tends to pick as you grind. I mix Attack with 5
minute epoxy and spread with a small disposable paint
brush. It soaks into any cracks and holds it together. It
also means you can orient it easily without wetting it.

I forgot what the phrase is about republish, but you can
use this info as you wish. Give credit/questions to Dave
Millis, me. Inga Wells does not cut, but we both use this
logon.

Dave Millis (rockdoc@epix.net)
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(Ed. Note: Terminology has always been a problem. There are
names used by mineralogists which are foreign to lapidarys,
and many mineralogists dislike (abhor)the lapidary names
for minerals. Nowhere is this more apparent than with names
of feldspars. I personally take a middle road and follow
the lead of Sinkankas (MINERALOGY), who was both lapidary
and mineralogist. In describing ALBITE, he says: Silvery or
pale bluish reflections of considerable intensity are often
noted in Albite, and this is then called MOONSTONE; when
such reflections display a variety of hues, the term
PERISTERITE is sometimes used. (caps mine) Note that neither
peristerite not moonstone is a mineral name; the mineral
is named albite.

Albite is the first mineral in a 6 member series called
the plagioclase series: Albite (moonstone and peristerite),
Oligoclase (sunstone), Andesine and Labradorite
(labradorite and spectrolite), Bytownite and Anorthite.
Note how many lapidary stones come from this one series!
I personally reserve the word SPECTROLITE for the gem grade
version of labrodorite which comes from Finland.
..hale)
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<MSG7>
Subject: NEW: Tools for Polishing with Diamond


In Issue 50, Richard mentions using diamond paste on a
hard felt wheel for polishing.

I am working with irregular shapes, usually (edge) gold
plated and would be very interested in other comments about
diamond paste use. I can give some details of my methods
and hope others will come back with their experiences.

"Hard Felt" shafted wheels for use in a flexshaft or Dremel
are too soft for me. I find that soaking the felt (totally
saturating) in a 10%-15% aqueous solution of hide glue
gives an excellent hardness which better holds the diamond
paste and its shape. I buy the highest strength and purest
(defatted) dry hide glue granules from woodworking supply
houses. This is far harder than common gelatin as it is
selected as a top strength wood adhesive. I think
Franklin's Liquid Hide Glue would give equal results but
they do have liquifiers in their formula I worry about...
but LHG does have preservative so you don't have to
dissolve it from the dry granules every time you want to
use it.

I also make a different form from a piece of 1/8" drill rod,
1-5/8" long, to which I adhere a chamois strip with solvent
based contact cement (as used in gluing Formica countertop)
for a single turn. The chamois strip is (usually) about
5/8" wide by 3" long. I let this dry overnight which gives
a tough, heat resistant, water resistant bond between the
steel "pin" and the chamois strip. Next, I saturate the
(dangling) strip with hide glue solution and wrap it around
the pin, taking care to wrap in the "winding" direction
(clockwise from the pin end). The glue-wet chamois is not
very tacky so I wind on a few turns of thin wire to hold it
in place until it dries. I dry it over silica gel for speed.
Once dry it is entirely solvent resistant and, unaffected by
the silicone oil base of the diamond paste and extender. By
the same token, a small brush and lacquer thinner can clean
the tool... but it is so simple to make these by the dozen
that there is no need to clean up and change grits.

For a different hardness, I cut 1/2" or 5/8" slabs of
phenolic board into small squares with a band saw and then
drill a 1/8" center hole. I press fit the same type of
pin as above into this hole, using contact cement as a
"lubricant". After a short cure time, I chuck this assembly
in a Dremel and shape the "square" into a "drum" against
my (running) bench grinder. The Dremel runs in a counter
(clashing) direction to the bench grinder and in a minute
or two becomes a cylinder. I shift from the bench grinder
to a belt sander and finish the tool to a flat cylinder or
"barrel" or tapered cone ....or whatever shape I want. The
phenolic is very tough and hard so it takes very little
diamond paste to charge.

I get the phenolic board from the scrap bin of our Dayton
Plastics outlet ($2.00/lb). They also have glass-epoxy
board of the same thickness but it doesn't work as well as
the phenolic (too hard?). As to suppliers, does anybody
think they see a difference in diamond paste from
Crystalite vs LapCraft (or other supplier).

...gtb

*---------------------*
* George Butts, KC8T
* Laurie Butts, N8CKI
* gtbutts@infinet.com
*---------------------*
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<MSG8>
Subject: BIO: Jim Newman


I'm Jim Newman and live with wife-mate June. We have been
in the hobby since the early '60s when the Aiken (SC) Gem
& Mineral Society was formed. My interests have included
all phases of the hobby except faceting. (Or "crystal
butchering" as I sometimes refer to it as, to my faceting
friends). I was involved with the EFMLS in several jobs,
and in the Wildacres program.

Because of health considerations, we moved here to the Due
West Retirement Center in January '96, and I have been
allowed to set up a small operation for cutting and polishing
in the basement. I am trying to get some of the residents
here interested in the hobby, and am making some progress.

One of my other interests has been micro crystals of gold and
silver, and I still have a rather nice collection of them
which I still intend to exhibit competitively one of these
days - but not in Jackson MS at the American/Eastern
Federation Show next month.

The newsletter is terrific and I'm enjoying every issue!

Jim Newsman
DWARF, Box 307
Due West SC 29639
<jimini45@juno.com>

-non-commercial reproduction rights granted-
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<MSG9>
Date: Tue, 23 Sep 1997 07:40:59 -0600
To: "'lapidary@mindspring.com'" <lapidary@mindspring.com>
From: SchneDJ@LOUISVILLE.STORTEK.COM
Subject: RE: Refurbishing an Old Lapidary Machine #60


Richard Dudley inquired about refurbishing some Star Diamond Lapidary
equipment. I recently inherited a lot of old Star Diamond equipment
(with documentation) so I thought I'd pass this along.

First let's start with the equipment. My 1969 Star Diamond catalog
lists four different grinding machines that are not combined with a trim
saw. They are the GP-6, GP-8, Super GP-8, and GSP-8:

GP-6: two 6x1 grinding wheels, one 6x3 expanding drum, and one 6" convex
head - $89.95
GP-8: two 8x1-1/2 grinding wheels, one 8x3 expanding drum, and one 8"
convex head - $158.40
Super GP-8: two 8x1-1/2 grinding wheels, two 8x3 expanding drums ,and
two 8" convex heads - $179.95
GSP-8: Two 8x1-1/2" wheels, three 8x3 expanding drums, and one convex
head. - $199.95

Wish those prices were still valid! The Super GP-8 is the model I
inherited (with original documenation). Here's the instructions for
the Super GP-8 for changing wheels:

To change grinding wheels, remove four nuts from the top of the wheel
cover. Remove small bolts from rear of cover. Diconnect main line
water from shut off cock. Lift off wheel cover. Sightly loosen jam nut
at left end of shaft by turning clockwise (left-hand thread).
Disconnect belt from pulley. Entire shaft assembly may then be removed
from housing. Remove sanding and poishing head or drum. Loosen bearing
spacers, etc., and replace. It is not necessary to remove either the
pulley or bearing on right end of shaft. Replace by reversing the
procedure. It is best not to tighten set screws on bearing until shaft
assembly has been located and jam nut tightened in pace. Replace belt
on plulley, install wheel cover and connect water system. Machine is
then ready for operation.

As far as replacing the wheels and/or belts, you have two choices
silicon carbide or diamond. The original equipment is silicon carbide
and is cheaper to purchase initially. Diamond is more expensive, but
cheaper in the long run when you consider how fast carbide wears out on
the tougher materials.

With lapidary grinding wheels, you also have two choices for bond - the
softer green (more common) and a harder (and cheaper) black bond. Green
wheels claim to be self sharpening. That is because of the softer bond.
They don't need sharpening (dressing) to expose new sharp grits.
Because of the softer bond, dull grit just tears away. The black wheels
don't wear down as fast, but they tend to dull and glaze over. So you
will need to dress them frequently to remove the glaze and expose fresh,
sharp grit.

For purchasing wheels and/or belts here are some possible suppliers.
For a more extensive list, you may want to consider the May 1997
Lapidary Journal buyers' directory which lists many sources of lapidary
equipment. These are some that I have already requested catalogs from
and they have been more than happy to send them:

All these are for 8" x 1-1/2" 100/220 grit Silicon Carbide wheels:
Black bond Green bond
Bourget Bros (310) 450-6656 $34.40/$37.60 N/A
Griegers (810) 304-7690 N/A $48.99/$51.99
Eloxite (307) 322-3050 N/A $35.00/$37.50
Kingsley North (906) 563-9228 $47.95/$51.95 $62.95/$68.95
Alpha Supply (360) 372-3302 $47.50/$51.50 $62.00/$68.00
Graves (800) 327-9103 N/A $46.95/$49.95
Thunderbird (505) 722-4323 $29.95/$42.05 $29.95/$42.05
MLS (612) 872-7211 $44.00/$49.50 $44.00/$49.50

And I just found this one and I want to call up and follow up on it to
verify what they mean:
Rough and Tumble (541) 459-3351 has listed a price "for a case package
of 5" green Camel brand wheels:
100/$49.50 220/$55.00
I wonder if they mean the price is per wheel in qty of 5 or the whole
case of 5???

Now if you want to go diamond, the going price for diamond grinding
wheels seems to be running around $200 each
<MSG10>
Date: Tue, 23 Sep 1997 07:49:06 -0600
To: "'lapidary@mindspring.com'" <lapidary@mindspring.com>
From: SchneDJ@LOUISVILLE.STORTEK.COM
Subject: RE: BUDDSTONE #61


I have an old "Gem Material Databook" (1957) Pub. Gem & Minerals
Magazine:

Buddstone: chalcedony or cryptocrystalline quartz
Dark vivid green, lighter & darker figured
translucent to opaque
refractive: 1.531 1.539
specific gravity: 2.58 - 2.65
hardness: 6-1/2 - 7
toughness: 7
cleavage: none
fracture: conchoidal
habit: mammillary, botroidal, massive, more brittle than agate

I to have a few slabs and cabs of this material. Wish I could get more
and I haven't seen any sources - yet - but I'm always looking.

"non-commercial reproduction permitted"
Jim Schnell
Storage Technology Corporation
schnedj@louisville.stortek.com


>
>I have a small slab of a material I have never seen before.
>It is a pale lime green color with a swirl of white thru
>it. There is a paper stuck to it with the name "BUDDSTONE"
>written on it. There is no other information available. It
>is a beautiful slab and I would like to know more about it
>and where it may be obtained. Any information would be
>appreciated.
>
>
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