Administered by Hale Sweeny (email@example.com)
This list digest contains the following message subjects:
1. LapDigest News for Issue No. 132 - Tues 4/7/98
2. NEW: Do We Consider Flintknapping Part of Lapidary?
3. NEW: Making Agates Red by Heating
4. RE: Making Agates Red by Heating
5. RE: Coloring Agate Slices--Historical German Method
6. RE: Red Tigereye?
7. RE: Red Tigereye?
8. RE: Red Tigereye?
9. BIO: Wayne Moorhead
10. BIO: Paul T. Ahlstedt
Subject: LapDigest News for Issue No. 132 - Tues 4/7/98
I have now updated the index through Issue 131, but due to
its large size, have had to break it in two parts. The two
files are now named: index1.txt and index2.txt. All BIOs are
in the index named <indexBIO.txt>, and all mastheads (if that
is the proper name) are in <indexDATE.txt>.
Also, I have noted that there is some confusion about how to
access the archives. I am working on an article describing
this in full, which should be ready by at most issue after
It is spring! Flowers! Azaleas! Pear trees! IT'S BEAUTIFUL!!
Subject: NEW: Do We Consider Flintknapping Part of Lapidary?
I was wondering if you have ever written about making arrow
heads from obsidian, or other things? If so, please direct
me to the proper area.
Ron: We have never done anything related to flintknapping,
and didn't even consider that to be a part of lapidary, but
I don't know why! Maybe we should! Maybe we should include it
in the list of things we discuss. Members: should we include
flintknapping as part of what this list is about? Write to me
at firstname.lastname@example.org and I will summarize the results and
report them here. hale)
Subject: NEW: Making Agates Red by Heating
Just have to add a little here, I recently saw on NHK TV
(Japan) a program about an agate carver, who heat treated his
agates to obtain a nice red color. Showed gray agate going
into ash filled box (3x3 ft), and a charcoal fire built on
top. They said the process took about a month! He carved a
goldfish from the stone with a good color that really looked
"right". Watching the carving with iron points on arbors over
a big box of grit or polish was an education.
Subject: RE: Making Agates Red by Heating
Sinkankas [Gemstone and Mineral Data Book, pp108] describes
the coloring process, basing much of the chapter on the 1913
work of Dreher, which was reported here in Issue 130. He also
describes the heating of agates to turn them red. I will
summarize, but not copy, his comments below.
Many agate pebbles and nodules found in streams have absorbed
enough iron to turn red when heated. Larger rocks may only
show red on outer layers, as they have not absorbed the iron
deeply enough. These small nodules must be carefully dried,
best after preforming. Bring up to heat slowly. Pebbles and
nodules may be embedded in sand in a suitable container and
heated in a kitchen oven, with heat increased in increments of
50 degF about every 30 minutes, till the oven has reached its
maximum setting. To cool, turn off oven and let stand
overnight to come to room temperature. He notes that pebbles
from streams in Brazil and Uruguay make great banded
This possibly answers the question as to how the Japanese
sculptor was able to turn the agate red by heating. The same
also probably applies to the red tigereye discussion.
Subject: RE: Coloring Agate Slices--Historical German Method
Very nice article on classical German method of dyeing
agate, with an important safety note: If you are going to
heat your Sulfuric Acid in order to "Set" the caramelized or
carbonized sugar solution, (don't use honey; it's too
expensive for a job that table sugar does better), please be
aware that concentrated Sulfuric acid does not boil; it
decomposes at about 180 degrees Celsius, with the liberation
of copious quantities of a dense, white cloud of Sulfur
Trioxide, which is viciously corrosive and toxic. (if it gets
on your skin, first it dehydrates by pulling moisture out of
the cells, and then it acts like the acid it has become; it
eats people!) I don't even recommend a fume hood for this
operation; If you have ever replaced the squirrel cage on a
"hood" fan, you'll understand why. Do it outside, on a
moderately breezy day, and be sure that the breeze is blowing
away from you and your house (or anyone else's!) In even
moderately humid air it recombines to form the (very) heavy
Sulfuric acid and drops out of the air within less that 100
yards. Don't use battery acid; you have to boil it down
about halfway before it's of any use, and it has a nasty
tendency to "bump" (explosively boil over) creating havoc on
whatever it boils over onto.
Now; dyeing other materials. "Everyone" has seen howlite
dyed to resemble turquoise or sugilite. Some people have
even been defrauded by unscrupulous dealers who represented
the dyed material as the real thing, which it closely
resembles. Commercially, and as a hobbyist's fancy, it is
done with Ty-d-Bol (R), although many other toilet bowl
cleaners will work just as well. (I have used Vanish(R) with
good results) Use the blue variety for Turquoise-dyed
Howlite, and the purple variety for faux Sugilite. Remember
to finish the stone all except for the final polish before
dyeing; otherwise you'll be repeating the dyeing step.
At least, though, the dye is relatively insoluble and will
withstand washing. Many a lady has taken a shower with her
"Lapis Lazuli" necklace on, and had her neck turn a startling
shade of blue which was difficult to wash off unless she used
I consider the use of Methylene Blue to enhance Lapis not
only fraudulent, but stupid! Nile Blue or Oil Blue O, both of
which are insoluble in water are much better choices; or if
for some reason, like having a lot of Methylene Blue on hand,
but none of the other, and wishing to "enhance" the color, it
should at least be "Mordanted" and then washed to make sure
that the color is fast. Mordanting is basically a process of
boiling the stone in a solution of alum, dyeing, then
"Setting" the mordant by heating in a strong solution of
If ever we buy a lot of suspiciously blue Lapis, we boil it
in alcohol for a while before attempting anything else with
it; if the alcohol turns blue, we repeat until it no longer
does. The funny thing is that the lapis thus extracted is
frequently more attractive than the dyed material; when
lapis is dyed, it all comes out the same color, and it is the
small variations in color of the natural stones that adds
We once got royally taken by a gentleman who had some
gorgeous Amethyst baroques for sale at a very attractive
price. I, being suspicious by nature, asked, "Are these
dyed?" "Oh, no;" the dealer said "You can't dye Amethyst!"
Shows what he knew. We took them home and boiled them in
alcohol. The Gentian (Crystal) violet fairly flew out of the
stones, reducing them in value considerably, but making
honest stones out of them. We consider it to be the height
of dishonesty to sell an "Enhanced" stone without telling the
buyer that it is; we feel that such a practice constitutes
blatant fraud, and should be frowned upon, just as is
oil-soaking emeralds to hide flaws.
non-commercial republication rights granted.
(Ed. Note: I failed to give a reference for the article on
the German coloring method. It is: Dr. O. Dreher, Farben des
Achates (Idar: E. Kessler, 1913) 20pp. hale)
Subject: RE: Red Tigereye?
In regards to Red Tigereye, you can turn the brown to red
with heat in your ordinary oven. The temperature required is
about 400-500 degrees. Bring temperature up slowly and
reduce it slowly as well. Unless it remains at the higher
temperature for some considerable length of time, you will
only get a surface change of color...Consequently, finish
your cab or whatever before heat treating the piece....
regards and good luck
Can republish my comments
Subject: RE: Red Tigereye?
<<One person said brown tiger eye, when heated for a while,
turns about a brick-red color. (snip) Can any of you
add anything to this?>>
Yep, easy to prove. Take a small scrap piece of the brown,
place it on a strip of steel, and heat the steel from
underneath, at a spot about 1/2" from the stone. Watch it
change. Caution, the doggone thing will be HOT so don't grab
it right away. Also if the stone has any oil or water on it
there may be a problem. Grownups, have your kids do this for
Subject: RE: Red Tigereye?
In response to your question about Red Tiger eye, yes, red
tiger eye does occur naturally. In fact it comes in Brown,
Red and Blue that I am aware of. I work for a Jewelry and
Lapidary supply shop in Sacramento Calif. and we have carried
it in the rough before many times! :)
I hope this answers your question :)
"non-commercial republish permission granted"
Subject: BIO: Wayne Moorhead
I'm the current President of the San Diego Mineral & Gem
Society, and have been doing lapidary and silver work for
about 6 years now. My wife publishes our monthly club
newsletter "The Pegmatite" and we're interested in shop tips,
tricks and pitfalls to pass along to our membership of 500,
and also the exchange bulletin editors who read our
publication (about 100).
I have various essential lapidary machines, (slab saw, trim
saw, cabbing unit, polisher) and also a sphere making machine
that I built with help and advice from club members.
Looking forward to participating in the discussions!
San Diego Mineral & Gem Society
San Diego, CA 92121
Subject: BIO: Paul T. Ahlstedt
We are pleased to be able to join this newsgroup, and would
like to offer a brief background about our company. P.T.
Ahlstedt Mining and Mineral Exploration started in 1993 with
the sole purpose of mining and marketing cabinet to museum
quality mineral specimens. Due to byproducts created by
mining operations, we then became involved in the faceting
and cabbing rough markets. Today, we are one of the major
players in the international gem trade industry. We offer
competition quality faceted gemstones and services (see our
ad in the classified "services" section of most major trade
publications), gem quality faceting and cabbing rough, cabinet
to museum quality mineral specimens, and a host of other
We join this newsgroup today with an acute interest in the
lapidary arts, and hope that we can both share, and learn
from all participants. While our primary interest is in
faceting, we hope that all of you can help to broaden our
knowledge of THIS most interesting artform (lapidary).
We are also pleased to announce (almost :-) our new webazine
called "The Gemking." It shall be a weekly publication
devoted to all aspects of lapidary arts, gem and mineral
collecting sites, shop helps, etc. It is near completion at
this time, and we shall post a URL and formal introduction as
soon as possible. We invite everyone to participate, and
have even provided a vehicle with which to do so at the site.
We look forward to visiting with everyone. Have a great day,
and happy cabbing!!!
Paul T. Ahlstedt
P.T. Ahlstedt Mining and Mineral Exploration
"Competition Quality Faceting Services"
Cut and Rough Gemstones Dealers since 1993.
1997 American Gem Trade Assn. "Cutting Edge" Award Winners
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