Edited and Published by Hale Sweeny
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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 245 - Thur 11/11/1999
2. RE: Dopping Problems
3. RE: Dopping Problems
4. RE: Dopping Problems
5. RE: How to Smooth the Dome on Cabs?
6. RE: How to Smooth the Dome on Cabs?
7. RE: How to Smooth the Dome on Cabs?
8. RE: Crushed Semi-Precious Stones
9. RE: Egg Making Machine
10. RE: Cutting Small Cabs
11. RE: Cutting Small Cabs
12. RE: WTB: marra mamba and chrysoprase
13. WTB: Sinkankas Gemstones of North America


Subject: LapDigest News for Issue No 245 - Thur 11/11/1999

WW1 ended 81 years ago today. Anne's uncle Charlie was
gassed in France in 1917 and bore the scars of that for the
rest of his life. He lived with Anne's parents, so I knew
him well. I entered the Navy in May 1942 and came home from
the Pacific in August 1946. That was 53 years ago. Today is
Veterans Day, and I looked, last night, at my High School
Yearbook, and looked again at the pictures of several
friends who did not come home from that war. For example,
Hal Major flew P-51s over Europe, and was shot down while
strafing flak towers in France during the invasion. Hal and
I went hunting on his father's farm in the summer of '42
while I was on leave - we didn't shoot anything, but we did
find a watermelon patch and rolled a few watermelons into
the creek to cool them, and came back late in the afternoon
and busted them open, and sat there and ate their hearts out.
That was the last time I saw Hal. He was a really nice guy,
and I remember him with a lot of fondness.

I know that WWII is foreign to most of you, but as you see
and hear the Celebrations today, please remember that there
are still a lot of us old guys who are not celebrating some
unknown event, but remembering friends who died in the War.
And remembering experiences we would rather forget. Enough!

One listmember wrote: "How about encouraging writers to the
digest to give their names and locations (city and state).
I often wonder if the writer might live just around the
corner or in Timbuktu." Remember the woman who wanted
crushed gemstones? Well I called her and it turns out that
she lives just 50 miles from my home. Emphasizes the point,
doesn't it? So please add at least your name and hopefully
your state when you send in a query or response.

God Bless all of you and keep you and your families safe
from harm.


Subject: RE: Dopping Problems

Speaking of getting stones warm for dopping, here is what I
use. I found an old coffee cup warmer. It is about the size
of a small saucer. I just plug it in and it warms up. I put
the stones on it that I want to dop. I am maybe a little
more careful with stones like opals but I have never had
any that ever got too hot. The dop wax seems to stick better
when the stone are nice and warm.


Subject: RE: Dopping Problems


When you make your dop sticks, make sure you pull out a few
'threads' of dop wax and save them (kinda like pulling
taffy). When you go to attach stones to the sticks, break
off a grain of rice sized piece of dop wax thread and lay
it on the back (which should be up) of the stone you are
going to attach to a stick. Heat the stone by holding it
with (needle nose) pliers or tweezers, passing it thru the
flame (don't hold it in the flame for more than a second
ever) until the dop wax 'grain' on the back starts to flow.
Set the stone quickly on a flat (hotpad) surface and press
the pre-waxed (and hardened) end of a dop stick on the back
of the stone. It should flow and make a good seal. Hold it
steady until it hardens. Cut your stone. By using the dop
wax itself you never overheat the stone. If your grain of
rice starts to boil you got the stone too hot. If it does
not actually start to flow its not hot enough.

I make my own dop sticks from dowels (and pencils and nails)
using traditional dop wax (I also use superglue and nails).
I put a 6 x6 x 1/4 in steel plate over a burner and set my
old, solid, mason jar lid (the kind with the glass seat) on
it and charge it with a block of dop wax. When it is soft
you can move it off the center to find a spot where it will
stay hot but not boil. The ends of sticks can be rolled in
the hot dop wax almost horizontally. Get a charge of wax
on the end and then quickly roll it on some Formica to shape
the end into a barrel around the stick (it should be barely
soft when you finish). Stand it in a dop stick rack (a chunk
of 2x4 with a grid of 3/8 inch holes drilled in it) until
ready to start putting on stones.

BTW, the plate is useful for heating stones if you want to
avoid direct flame contact.

Hope this helps.

Kreigh Tomaszewski
Please visit our family web pages at

Subject: RE: Dopping Problems


Many years ago I parted company with dopping wax. The
final straw with that contrary, mind of its own stuff came
about the moment that I dopped the ends of four fingers as
I reached for a preform cab in its supposed container.
That episode, in addition to the countless pop-offs which
occurred as the wheel became "rough," was my incentive to
sack the wax. Since that time I have used epoxy and flat,
bevel head machine bolts, and have had no pop-offs and my
fingers are all intact.

I built two wood frames to support the bolts in vertical
position. One frame supports 25 bolts for 40 x 30 and
larger cabs, the other supports 50 bolts for smaller cabs.
Frame dimensions are: 2-1/2" wide, 3-1/2" high, 21" long
(short enough to fit in the kitchen oven). The removable
top board has two rows of staggered bolt holes and is held
in place with wing nuts. To quick dry the epoxy I place
the filled frame in the oven for 30 minutes at 150 degrees.
The bolts I use are defense industry surplus and have
precision flat heads. This method enables the dopping of
several hundred stones in one sitting.

Stones are removed by placing under a rubber heel on carpet
and pushing against the bolt. Epoxy will pull out the
bottom of soft stones such as tigereye and obsidian but
they will release if placed in vinegar overnight.

Lou Harms
Independence, MO

Subject: RE: How to Smooth the Dome on Cabs?

<<My question is....How do you get the perfect smooth dome
on cabs?>>

Try a test: color a stone with a permanent marker (don't do
it on a soft stone!). As you sand the surface away, you can
see exactly where you've been. Recolor when you move to the
next sanding step. It helps key you in to exactly what your
hand is doing. Or not doing, as the case may be.

Dana Carlson

Subject: RE: How to Smooth the Dome on Cabs?

When polishing obsidian I usually take a pencil & smear the
lead back & forth across the face of the stone to be cabbed.
As you form the edges and on up to what you think should
be the crown, the pencil markings should be all gone,
providing you grind and sand the stone evenly all the way
around and over the top.

I have never tried this on any other type of stone, but who
knows it might work. I know it does on obsidian. Let me
know how you make out.

John Ratcliffe
Kamloops, BC

Subject: RE: How to Smooth the Dome on Cabs?

The one thing that works for me is an expanding-rubber drum.
When I press the stone into the sandpaper the backing rubber
deforms and makes nice smooth curves.

The mass-producers don't worry about small flats: They toss
hundreds of stones into a tumbler for everything after the
initial shaping. (Note the depressions in the flat backs of
inexpensive cabs.)

I have never been happy with my results with hard
flat-surfaced wheels. Anyone use those curved maple spools
or cups? Those seem very homebuilder-friendly.


Subject: RE: Crushed Semi-Precious Stones

Dear Barbara,

With respect to crushed gemstones, there is a gentleman here
in Perth, Western Australia who is part owner of a mine in
Mogok, Myanmar. They produce a wide range of crushed
gemstones for use in " paintings ". These artworks are
mainly religious works for use in Catholic churches and
convents. They use stone crushed to approximately the size
of grains of sugar which is then glued onto a conventional
base and framed as one would an ordinary painting. With the
right play of light, the results are fascinating.

The array of stone types they use covers both precious and
semi-precious - garnet, peridot and party colour sapphire
being popular - and I am given to believe some low grade
ruby and emerald is also used. The gentleman's name is Mr
Neville Cole and I have called him for you today. He is
happy to discuss your requirements with you at your
convenience. Indeed, he is happy to talk to anyone looking
for a source of stones from Burma. Like most miners, he is
often away for a few weeks at a time. So I will pass on his
telephone number to you and you may wish to call him from
time to time until you catch him. His mobile number is
+ 61 414474704 and there is an answering service if he is
not available. Please remember we are 12 - 15 hours ahead
of the U.S.

>From our own product range I can supply low grade
chrysoprase for crushing. Equally our nickelian magnesite
( yellow to lime green ) and our gaspeitic magnesite (lime
green to green) should crush OK.

To echo Hale's comments, fineness is a factor to be
considered. As is purity. With respect to fineness, our
material will retain colour to, say, sand grain size but I
have never had occasion to reduce it to a powder. Easy
enough to test by dollying some up by hand in a dolly pot
as the gold prospectors do. However if your experiments
work and you require the material in quantity, there would
normally be an increasing crushing cost proportionate to
the decrease in size.

As to purity, this is primarily a function of the quality
of the feed stock. The higher the quality of the material
being crushed, the cleaner the end product. And in most
cases, higher quality feed stock will translate into higher
front end cost. If you check the archives, there is an
interesting article on this by Mark Liccinni in which the
refers to the collection of pure lapis lazuli dust for use
in high grade paint pigment.

The alternative (if purity is a requirement) is to process
lower quality material - either before or after crushing -
to remove impurities. This may be more economic than using
high quality feed stock. If you would like to try it with
chips of our stone you are more than welcome. At present I
have about 60 kg of small chips in stock ( simple floor
sweepings, some good, some rubbish). If you would like to
experiment by picking through them, I will happily give you
your first 10 kg for free provided you pay postage ( or a
swap for something of the same value as the postage -
airmail on 10 kg, not including packing, is about
$US 100.00 ).

Best wishes in your endeavours,

Craig White
Chrysoprase Mines of Australia

Subject: RE: Egg Making Machine

I think an egg shape (in two dimensions) is really a blend
of two different ellipses, asymmetrical so that one end is
fatter than the other. You make an ellipse by putting two
tacks into a board, putting a loop of string around the
tacks, and pulling both strings tight with a pencil you
trace around the tacks. constrained by the strings. The
parameters for the shape of the ellipse are the distance
between the tacks and the length of the string loop.
Rotate this two dimensional shape along the axis of the
tacks to make an 'egg'. From the geometry they almost have
to be turned on a lathe (and perhaps hand finished at the
cut-off end{s}).

I'd love to hear another alternative (other than computer
controlled cutter on a stable column, or loving hand work).

Kreigh Tomaszewski
Please visit our family web pages at

Subject: RE: Cutting Small Cabs

Hi All -

Another trick for small dops is to get some brass rod from
your local welding shop to use as dops. They come in various
diameters. By taking a piece of channel iron and cutting a
slot in it at 90 deg. to the side just wide enough for a
hacksaw blade you have a nice little miter box. By stacking
in the rods you can cut a bunch at one time.

If you are cutting a bunch of small rounds that are of the
size of the rods that you have, all the better. By using
superglue and a piece of matchbook cover or postcard for a
spacer just cut to the brass and you have your outer shape
and size.


Craig Nielson

Subject: RE: Cutting Small Cabs

OK Hale, I've got a couple more pennies to toss into this
discussion. And this works for cutting to size, especially
for small stones.

Mark your slab with a template so you know the size cab you
want and trim around it, but don't touch the line. Make
sure your line was to size by using a pointed scriber (I
use an sharpened length of aluminum TV ground wire).

Rough grind (or fine if softer rock) the edges left from
trimming up to, but not quite touching, your scribed shape.
You should have a square edge (90 degree angle) and a
smooth outline shape that is just a hair too big. Use a
fine wheel and carefully make a very small bevel
(45 degree) around the bottom until the bottom is just a
hair smaller than the template hole.

Now we start trimming the top edge to bring it to shape in
steps. Imagine using a super sharp knife edge to trim off
the rock from just above the bevel at the base to just
inside the scribed line on the top. We want a hairline thin
band between the top of the bottom bevel and the bottom of
the top trim. Grind this around; it should still be just a
hair larger than the template.

Repeat many times, each time lifting the base a little and
moving towards the center at the same time with each 'cut'
on your grinding wheel. If you do it right you will end up
with a whole bunch of rings (when viewed looking down on
the top of the cab), each the same shape (and centered in)
as the template (and the stone is still just a hair too big
to slip thru it). Now you have the shape roughed out and
need to be off your coarse wheel.

So far we've been working around the stone. Now, on the
fine wheel, we're going to work from the base to over the
top. Each time we roll we start at a different point around
the base (1/4 to 1/3 the way around), using a light touch
so we trim the edges and not the small flat faces of the
rings. Over and over, around and around. Each rotation
across the wheel goes from the ring just above the base
bevel smoothly until it is just over the middle of the top.
Repeat until you have the shape smooth and the stone just
barely be forced thru the template (but don't push it quite
that hard) - the rest of the edge will disappear in sanding
and polishing, and the stone will exactly fit your template.
Do the same rotation sequence from base to top middle for
each sanding grit. Polish likewise.

With small stones, especially round ones, and a little
practice, you can align the dop stick roughly with the axis
of the grinding wheel and 'roll it' to get the edge trims,
tilting the base of the dop stick away from the wheel a
little more with each level. It is a little harder with
ovals to do this and keep the shape right.

If you do this right there is no way to produce a flat
spot. If you do, you have not made a smooth motion through
the entire length of whatever cut you were making or pressed
too hard thru part of the stroke.

And if you want real fun, try cutting 2x3mm opal cabs for
replacement side stones on rings. I'll give you a hint, a
micrometer helps. The amount the first ring needs to be
larger than the template (desired size) at the beginning
can be calculated - its the amount that will be removed by
the rotation grinding, sanding, and polishing... 80 grit is
approximately 7.5 thousandths of an inch in diameter. 120
grit is approximately 5 thousandths of an inch in diameter
and needs to remove between 20 and 30 thousandths of an inch
of surface (you have two sides) to eliminate the scratches
and pits of 80 grit. 220 grit is approximately 2.5
thousandths of an inch in diameter and needs to remove
between 10 and 15 thousandths of an inch of surface (you
have two sides) to eliminate the scratches and pits of 120

600 grit is approximately 1 thousandths of an inch in
diameter and needs to remove between 3 and 5 thousandths
of an inch of surface (you have two sides) to eliminate
the scratches and pits of 220 grit. Aluminum Oxide 305
pre-polish is approximately .2 thousandths of an inch in
diameter and needs to remove between .4 and .8 thousandths
of an inch of surface (you have two sides) to eliminate
the scratches and pits of 600 grit.

Polish is approximately .001 thousandths of an inch in
diameter or smaller and needs to remove between .1 and .2
thousandths of an inch of surface (you have two sides) to
eliminate the scratches and pits of 80 grit.

And thanks to Henry E. Paul and Albert Ingalls for
publishing the details on grit sizes.

Hope this helps.

Kreigh Tomaszewski
Please visit our family web pages at
Really, Kreigh, that is MUCH more that a couple a pennies!
More like a quarter!! ( smile) hale

Subject: RE: WTB: marra mamba and chrysoprase

Hi folks,

Let me just second Mark-in-Oregon's praise of Craig White's
Australian chrysoprase.

I just hand-cut, hand-drilled, hand polished, eighteen beads
(yes 18 of 'em! Never again, folks, never again!) of Craig's
"B" grade material for a bracelet for an artist friend.

By the slowness of sawing and drilling, the chrysoprase
strikes me as an eminently tough and dense material. The
polish it takes is correspondingly spectacular. The very
slight hint of milky opacity in vibrant green makes the
polished end result look like a living green table grape.

And now the usual Surgeon-General's Statement: No, I don't
own shares, nor do I have any other business connection
with Australian Opal Mines...

Ecclesiastes 10:19
Hans Durstling
Moncton, Canada
Freelance writing. Feature stories, technical ad copy,
clear manuals, bid documents, simple english, videos,
speeches. Email for publication and client list.

Subject: WTB: Sinkankas Gemstones of North America

Hello Hale and members,

I am looking for Volume ONE (1959) and Volume TWO (1976) of
John Sinkankas' GEMSTONES OF NORTH AMERICA. I'd pay a
reasonable amount, plus shipping, for copies in good
condition. Shucks, for good copies, I'd even pay an
outrageous amount plus shipping.

If you have an unneeded copy, please contact me off list.


Gail Clark

(Hale: What a splendid thing you are doing with Lapidary
Digest! Thank you for your own helpful expertise and for
all your effort that makes this list "must" reading for
anyone interested in lapidary. )
You keep talking like that and you can have anything I have!
Just to show you, I did a 'Net search of used book stores'
inventories, and looking at ABE alone. I found 20 copies of
various editions of these books, at prices ranging fron $20
per book to $75:

There are several such integrated used book lists available
on the Web, other than ABE. hale
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