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This list digest contains the following message subjects:
1. LapDigest News for Issue No. 74 - Sat 10/18/97
2. NEW: Mud Saws (Was- Saw for Cutting a 550 lb Geode)
3. RE: Saw for 550lb geode
4. RE: Saw for Cutting 550lb Geode
5. RE: Clamping Rocks in a Saw Vise
6. RE: Clamping Rocks in a Saw Vise
7. RE: Clamping Rocks in a Saw Vise
8. RE: Clamping Rocks in a Saw Vise
9. RE: Vertical Lap Problems
10. BIO: Comments on- Raymond Rodebaugh
Subject: LapDigest News for Issue No. 74 - Sat 10/18/97
I have heard from a member who had trouble with the last
issue. That member is on AOL and it seems that AOL turns all
messages greater than 2K in size into an attached file which
must be downloaded and read by a word processor. I have no
idea when I send out an issue what size it is; I only know if
it is short, long, or extra long! I'll work on this. Did any
of you also experience any reading problems? If so, please
let me know.
Also the member said that the trivia column were not aligned;
it was aligned when it left here! I must remember to compose
columns so they are aligned in anyones computer!
The paper on Feldspar by Anita Collins, President of the Ga.
Mineral Society, is given below. Feldspars are important
lapidary materials, and I am happy to publish her paper here
for you. Thank you Anita, for allowing us to present it.
Here in NC, the weather is chilly and dreary; hope it is
better where you are and you will be able to have a great
weekend! Stay safe, and HAVE FUN!
Subject: NEW: FELDSPAR
Anita D. Westlake
The word feldspar literally translates to: feld, meaning
field, and spar, meaning "easily cleaved material". It
refers to any of several crystalline aluminosilicate minerals
found in abundance in the earth's crust.
Minerals in the feldspar group are found in many places
throughout the world, in pegmatites, even meteorites, and
pass through all rock and ore-forming processes: igneous,
metamorphic, hydrothermal and sedimentary, yet only rarely do
they occur as gemstones. Feldspars are the most diversified
and the most extensively investigated minerals on earth,
though they only recently commanded the attention they
deserve. It wasn't until the middle of the eighteenth
century that minerals in this group were even vaguely
mentioned in Wallerius's popular work "Mineralogy" written in
1753. They were briefly described as varieties of a "spar
dense and lustrous" distinguished only by their colors of
white, gray, and the occasional red. It wasn't until the end
of the 18th century that serious crystallographic and
chemical research began. Today, at least 40 varieties of
feldspars have been identified, with a dazzling array of
colors and distinctive features.
Feldspars have a specific gravity which varies between
2.5 to 2.7 depending on the chemical composition. The
hardness ranges from 6 to 6.5. Its fracture, other than
along the cleavage planes, is subconchoidal to uneven. Most
feldspars crystallize from a melt in igneous rocks. Their
crystals are tabular, flattened and most are complexly
All feldspars have certain physical characteristics in
common: they have 2 good easily developable cleavages, one
which is perfect, usually known as the basal plane. Here, the
luster is pearly and the from the cleavage cracks parallel to
this face, brilliant iridescent colors are sometimes
reflected. The second cleavage, less perfect than the first,
is parallel to the pair of faces which truncate the acute
sides of the prism. The cleavages of monoclinic and triclinic
feldspars are essentially the same with the following
exception: the monoclinic crystals have cleavage planes that
are exactly perpendicular to each other, giving them the name
"orthoclase" which means "cleaving at right angles."
triclinic feldspar, the two cleavage directions are not quite
at right angles. These are referred to as "plagioclase",
meaning obliquely cleaving.
The presence of lamellae, which are thin, platelike
layers within the crystalline structure, gives rise to the
"Schiller Effect". This is an iridescence caused by the
scattering of light between the layers. In Labradorites, the
Schiller Effect is best developed, creating a lovely color
play in shades of green, blue, gold and yellow. The color
may be homogeneous or vary within a single feldspar crystal.
Research is currently being conducted on lower quality
plagioclase feldspar mined in Arizona to see if gamma
radiation will produce a color shift or enhancement. Initial
tests suggest this possibility exists.
POPULAR STONES IN THE FELDSPAR GROUP
Originally called "Amazonstone" because it was found
near the Amazon River, this term was also used to describe
CRYSTAL SYSTEM: Triclinic
COLOR: Light green, blue-green or bluish with a mottled
appearance and sometimes a fine crisscross network of light
striations (which help to distinguish it from certain jades
GENESIS: It is found in metamorphic rocks, intrusive magmatic
rocks and pegmatites. The finest examples of Amazonite in
the United States are found in Amelia Courthouse, Virginia.
Pikes Peak, Colorado also boasts a variety of Amazonite found
in cavities in a coarse pegmatite granite with smokey quartz
crystals, often of huge size.
LORE: Worn by gamblers to attract money. It was also used by
anyone taking a chance to ensure success.
The most magnificent of all the feldspars, Labradorite
occurs on the coast of Labrador, Canada. Although it is
often a dingy, dark gray, the brilliant play of colors and
unexpected flash combine to make this a most remarkable
stone. It is a lime-soda-feldspar, comprised of approximately
55% silica, 25% alumina, 2% ferric oxide, 11% lime, 4% soda,
with a touch of Potash. Feldspars with this composition are
referred to as Labradorite, whether they come from Labrador,
Madagascar, Scandinavia, or the United States.
The stone is cut, not with facets, which would destroy
its reflected rays of color, but either perfectly flat or
with a slight convex surface. It must be cut parallel to the
reflecting surface, or no play of color will be seen. The
sudden appearance and disappearance of brilliant colors is
its most striking feature and gives us the word
An interesting specimen of Labradorite from Russia
displays a perfectly recognizable image of Louis 16th. The
head is of the finest azure-blue and stands out from a
golden-green background. It is topped by a beautiful
garnet-red crown with a border of rainbow colors and a small,
silvery shining plume. In 1799 the owner received one
quarter of a million francs for it.
It was customary to use Labradorite in the
representation of objects with a metallic color such as the
iridescent wings of butterflies. In the beginning of the
19th century, reliefs of Mandrill baboons were very much in
vogue, and Labradorite was used to color the snouts of these
most colorful animals.
CRYSTAL SYSTEM: Triclinic
COLOR: Blue, green, yellow are the most common colors, with
copper-red being the most rare.
GENESIS: Widely distributed throughout the United States, it
is found in great abundance in Lewis and Essex Counties in
New York in situ as boulders in glacial deposits. These
boulders can be traced all the way down to Long Island and
New Jersey, and were so numerous in one river in Lewis
County, it was named "Opalescent River". Large quantities
were quarried at Keesville, NY for monumental and building
purposes. It is found in Pennsylvania, Arkansas and North
Carolina, but the gem quality variety is only found in
Labrador, Canada and Finland.
LORE: In ancient times, Labradorite was considered a general
"good luck" stone. In recent times, it has become popular
among New Age devotees as a spiritual, psychic-enhancing
Moonstone refers to the colorless, translucent, or
almost perfectly transparent feldspar which in a certain
direction reflects a bluish, milky light that has been
compared to the light of the moon. It has also been called
"girasol", "fish-eye", "wolf's-eye", "Ceylonese
"Water Opal". Very good glass imitations of moonstone are
frequently used in expensive jewelry. These "fakes" are
denser and less hard, and are only singly refracting, whereas
real moonstones are distinctly doubly refracting.
CRYSTAL SYSTEM: Monoclinic
COLOR: Almost colorless, tinged with yellow, whitish to
silvery white with a blue shimmer.
GENESIS: The best moonstone is found in Sri Lanka, and is
often referred to as the "National Stone of Sri Lanka". It
is collected by hand by miners who dig deep, narrow holes
in the earth. They lower themselves by rope to the bottom of
these pits, fill their wicker baskets with loose dirt and
gravel, and hoist the baskets up to the surface. It is then
washed by hand and the gem quality moonstones are picked out
of the gravel. The finest specimens in North America come
from Allen's Mica Mine in Amelia Courthouse, Virginia.
LORE: It is said to counteract the negative influences of the
number 13. Amulets of moonstone were hung in fruit trees to
produce abundant crops. It was thought to protect against
wandering of the mind, insanity and epilepsy. It was
attributed to improving physical strength and reconciling
lovers. If held in the mouth, a moonstone was supposed to
help decide matters. It was even used to hypnotize people.
In the Orient, moonstone was believed to be the solidified
rays of the moon, and the glimmering light within was the
light of the good spirit that lived in the stone.
Occasionally, under magnification, a peculiar flaw appears:
a long inclusion resembling a centipede.
A somewhat rare variety of transparent orthoclase, Noble
Orthoclase is nonetheless not considered valuable. It is
sought by collectors and connoisseurs for their collections
but is virtually unknown to the casual gem collector.
CRYSTAL SYSTEM: Monoclinic
COLOR: Mid to golden yellow, it is perfectly transparent with
a vitreous luster. Noble Orthoclase is most commonly faceted
into a "Step Cut" and the gems are usually free from
GENESIS: It is mainly found in pegmatites in Madagascar.
Known for their transparent, gemmy quality, sunstones at
one time were believed to contain metallic copper. Very thin
scales of hematite are arranged parallel to the direction of
perfect cleavage. The glittering sheen of the sunstone is
due to the reflection of this brilliant red metallic light
from the surface of these scales. At the beginning of the
19th century, sunstone was considered a great rarity and was
priced accordingly. Only a few small pieces were known, and
they came from Sattel Island in the White Sea.
CRYSTAL SYSTEM: Triclinic
COLOR: Specimens are commonly colorless or straw-yellow, but
some rare crystals have areas of red and/or green coloration.
These vary from pale to intense and may contain zones of red,
green, schiller or any combination of the three. The
schiller consists of round, thin, extremely reflective
platelets that are opaque to dark brown. Inside the crystal
they appear pink but near the surface have a white, metallic
GENESIS: Sunstone is found in a basalt flow near the Rabbit
Hills in Lake County, Oregon, as well as Siberia, Norway, and
Statesville, North Carolina. A rare variety of green
sunstone is found in Media, Pennsylvania.
LORE: No myths or folklore can be found in past history
regarding the sunstone, but current New Age thought links it
to protective energy. It is said to lend extra physical
energy in times of stress or ill health.
Feldspar, in all its chemical compositions, habits and
colors, is a fascinating mineral group to study and collect.
In its most mundane usage, it is ground up for a polishing
agent in toothpaste. In its highest and most noble form, it
is faceted as a rare and beautiful gem. It is at once simple
and sublime. Ralph Waldo Emerson once wrote: "A man is like
a bit of Labrador Spar, which has no luster as you turn it in
your hand until you come to a particular angle, then it shows
deep and beautiful colors."
Lapidary Journal, December 1994: "SRI LANKA'S GLITTERING
GRAVEL" by Stork Halstensen
Rock & Gem, August 1994: "PIKES PEAK PEGMATITES" by Steve
SIMON & SCHUSTER'S GUIDE TO GEMS AND PRECIOUS STONES, Simon
& Schuster: NY, 1986
THE CURIOUS LORE OF PRECIOUS STONES by George Frederick Kunz,
Dover Publications: NY, 1971,c1913
GEM MAGIC by Cornelia M. Parkinson, Fawcett Columbine: NY,
CUNNINGHAM'S ENCYCLOPEDIA OF CRYSTAL, GEM & METAL MAGIC by
Scott Cunningham, Llewellyn Publications: St.Paul, MN, 1988
Reviews in Mineralogy, V.2: FELDSPAR MINERALOGY,
Mineralogical Society of America: Washington, DC, 1983
THE FELDSPARS: PHASE RELATIONS, OPTICAL PROPERTIES, AND
GEOLOGICAL DISTRIBUTION by A.M.Marfunin, Israel Program for
Scientific Translations: Jerusalem, 1966
GEMS AND PRECIOUS STONES by George Frederick Kunz, The
Scientific Publishing Co: NY, 1990
PRECIOUS STONES by Dr.Max Bauer, Charles E. Tuttle Co.
Publishers: Rutland, VT, 1969
ENCYCLOPEDIA OF MINERALS AND GEMSTONES, 1976
COLOR ENCYCLOPEDIA OF GEMSTONES, 1977
Anita D. Westlake PHONE: (404)727-4066
Robert W. Woodruff Library FAX: (404)727-0053
EMORY UNIVERSITY, Atlanta Georgia EMAIL:firstname.lastname@example.org
An earlier version of this article was first presented to the
Georgia Mineral Society's Mineral Section Meeting on June 21,
Subject: NEW: Mud Saws (Was: Saw for Cutting a 550 lb Geode)
Wow Hale, you caught me! When I asked about mud saws (well
before the birth of this digest), you sent me the following
"Lapidary Journal has published 5 articles about mud saws.
1. Building a Giant Saw 63:09:654
2. Constructing a Mud Saw 83:12:1352
3. How I make Do 76:10:1782
4. Mud Saws 76:07:1048
5. Slow Does it with Big Mud Saw in
Petrified Wood 64:05:331
You can order reprints by phone by calling 1-800-676-GEMS and
giving them the titles and references above. They charge $2
per reprint and $1 for each 5 reprints, so your order would
cost $11.00. You can use your credit card to pay for them.
Their reprints take several weeks to come (maybe 6 to 8)."
So far, I havn't ordered the reprints :( so I can contribute
very little else except for comments about the basic concept.
Simply put, a rather long wire (cable) is dragged across the
rock after having a slurry of grit applied. The grit does the
cutting (very slowly), and at the same time wears the wire,
so eventually the wire must be replaced. Have no idea of how
long it takes to go through a foot of rock with one of these
monsters. This is still on my lengthy list of things to do if
I ever get a round to it
non commercial republish permission granted
Subject: RE: Saw for 550lb geode
Fran Allen and Ken <Fallen1969@aol.com> wrote:
<<Does anyone have homemade plans for making a large rock saw
with a six foot blade? We have a 550 lb geode we would like
to cut. Help!>>
As an alternative, you might consider renting the use of one
of those large diamond-bladed saws that are used for curb
cuts and other street repairs. I'm not sure if they go up to
six feet, but I've seen some about four feet in diameter.
Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
Subject: RE: Saw for Cutting 550lb Geode
There is a business in St. Johns, AZ that has a saw with a
six foot blade. I have lost their name and address. I don't
know if they do custom cutting or not. They spent a lot of
time taking us on a tour of their plant. Unless you have a
lot of them to cut, it might be better to ship your rock to
some one with a saw.
Don, the ramblin rockhound.
Subject: RE: Clamping Rocks in a Saw Vise
I use Elmer's glue to "dop" my rough rock to a 1x2 or 2x4. If
it is very irregular, I will take small pieces of dop sticks
and push them under the rough until I have it level and
orientated the way I wish to cut it. I will sometimes use
this method just to cut a "false" table in the rough so I can
grab it better to make the actual cuts. By this I mean I will
use the procedure listed above but make just a single cut on
the opposite side of where I really want to cut the rough. By
doing this I now have a flat surface I can grab in the vise
or I have a nice flat surface to glue my 2x4 dop to and like
water glass I can put the heal of the stone in water and let
it soak to remove the 2x4.
On the subject of the mud saw i think you can at least find
pictures of a mud saw in John Sinkankas' book.
non-commercial republish use permitted
Subject: RE: Clamping Rocks in a Saw Vise
I corrected my problem of securing odd shaped specimans in a
vice by simply drilling 4 holes in the side of the vice
closest to the blade (obvious). Two holes in the rear vice
plate & two holes in the front vice plate. I then threaded
the holes and inserted four bolts in these holes, then
tightened them. The holes only need to be 1/2 " deep and
1 1/2 - 2 " apart. The bolts only need to be protruding out
1/4 - 1/2 ". Bolts should have a flat head, which gives a
much greater grasping power than your regular stove type
heads. The irregular shaped speciman can then be clamped not
in the vice but simply into these protruding bolts. This
ended my problem of specimans coming loose, and at the same
time ended needless waste of the speciman that was in the
Morgans Antiques<->2nd Hand<->Rock Shop
1402 E. St. Patrick Street, Rapid City, S. D.
--non commercial reprint permission granted--
Subject: RE: Clamping Rocks in a Saw Vise
G'day; I use a chain/pipe vice. This is a vice that
plumbers and engineers use to hold pipes and thick cylinders
whilst cutting them.
The jaws are shaped in two V's and move to and from each
other with the usual sort of screw, but the V's are stepped.
One selects an approximate distance for the jaws, and then a
chain - exactly like a motor-bike chain (do they still use
them?) is passed over the top of one's rock and the end has a
kind of hook with a cylindrical nut attached. The hook is
pushed into the chain, and the cylindrical nut is pressed
into a slot, and upon turning the nut, tightens the chain
against the rock. A little bit of - well, reasonable abuse
will show whether the rock is held really fast and away you
go! Very difficult to describe without a sketch, but - well,
like I said, try and imagine it.
Having got a flat face to the rock, I 'glue' it with dopping
wax to a small hunk of scrap timber cut like an L This can
then be held in a normal lapidary saw vice. My slabbing and
trim saws are home-made setups which have worked well for
about 25 years. Water coolant with the slab saw, and a very
light Shell Co. transformer oil is used with the trim saw. I
need waterproof aprons with both these and also the grindery
and polishing setup. That's home made too. Think about what
you need to do something. Look around at what you, your mates
and the local junk shop have, think again only a bit sideways
this time, use a few tools, borrow from your long suffering
mates those you haven't got BUT RETURN THEM PROMPTLY - and
soon you have what you need without taking out another
mortgage on the house! This way you double the fun!
Subject: RE: Clamping Rocks in a Saw Vise
Attach a piece of 1/4" plywood to the inside of both jaws of
your vise. When you clamp an irregularly shaped rock in the
vise, the protrusions will sink into the softwood and
nothing, but nothing, moves.
Subject: RE: Vertical Lap Problems
Great Idea Hale, about using a 1x3 cut out like a door handle
..now all I have to do is remember how to dop the old way. I
still have my light bulb dop stove that works very well, and
many dop wax sticks, but I've been using 5 minute epoxy for
so long now I forget. I hope it's in the index somewhere :)
Thanks Hale and take care.............Dave
Dave Daigle, Edmonton, Alberta
The Edmonton Tumblewood Lapidary Club
Subject: Comments on BIO: Raymond Rodebaugh
Raymond F. Rodebaugh wrote in his BIO:
<<My computer at work is now surrounded by quartz crystals.
It doesn't seem to help.>>
Loved your BIO Raymond!
I was told by my network administrator that putting quartz
near your computer is an absolute no-no! Apparently the
vibrations of the quartz (even ones as small as in quartz
analog watches) can cause distortions on your hard drive.
Has anyone else heard of this?
Toronto, Ontario, Canada
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