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LAPIDARY ARTS and FACETERS DIGEST
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Issue No. 219 - Friday, October 3, 2003
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Moderated by: Thurmond Moore III
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Committed to carrying on the fine works of
Hale Sweeny and Jerry Dewbre
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POST TO EITHER LINK BELOW:
lapidary@caprock-spur.com
faceters@caprock-spur.com
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VISIT OUR WEBSITE TODAY
http://www.gemcutters.org
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Hi all,

Great job, lots of post early submission. Better for
me, better for all of us. Thanks. Have a great
weekend. I am hosting a rock humt and BBQ
this weekend so I know I will.

Thurmond

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Index to Today's Digest

01  RE: Solid Black Facet Rough
02  RE: Solid Black Facet Rough
03  RE: Solid Black Facet Rough
04  RE: Solid Black Facet Rough
05  RE: Solid Black Facet Rough
06  RE: Solid Black Facet Rough
07  RE: Solid Black Facet Rough
08  RE: Solid Black Facet Rough
09  RE: Solid Black Facet Rough
10  RE: Solid Black Facet Rough / Cutting Ovals !
11  RE: Cutting Ovals !
12  NEW: What is a Gemstone?


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Message:01

Subject: Re: Issue No. 218 - Thursday, October 2, 2003
Date: Thu, 2 Oct 2003 22:27:31 EDT
To: lapidary@caprock-spur.com
From: Astronal@aol.com

Todd:  Black jade makes a nice faceted gem.

Astronal@aol.com

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Message:02

Subject: Re: Issue No. 218 - Thursday, October 2, 2003
Date: Thu, 2 Oct 2003 22:37:49 -0400
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: Donald Allen <donallen@gwi.net>

RE: Solid Black Facet Rough?
  You may want to ask your customer if or not it had a metalic look?
It coud be marcasites, if so.    If it was stone like, It was probably
Black Onyx, as this is sometimes faceted with a high polish. These,
both, have been in fashion, of and on, for a long time and every so
often comes up again. There both popular with Art Deco type Designs.

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Message:03

Subject: Re: Issue No. 218 - Thursday, October 2, 2003
Date: Thu, 02 Oct 2003 21:01:30 -0700
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: Mark Zirinsky <mz@mho.net>

for an absolutely black material, and a red mess elsewhere, use either
hematite or psilomelane.

- Mark Z, Denver

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Message:04

Subject: Re: Issue No. 218 - Thursday, October 2, 2003
Date: Thu, 02 Oct 2003 23:13:56 -0400
To: LapidaryArtsDigest <lapidary@caprock-spur.com>
From: Kreigh Tomaszewski <Kreigh@Tomaszewski.net>

LapidaryArtsDigest wrote:
> ====================================
> Message:01
>
> Subject: Solid Black Facet Rough?
> Date: Wed, 1 Oct 2003 18:30:47 -0600
> To: <faceters@caprock-spur.com>
> From: "Todd" <td_gunz@yahoo.com>
>
<snip>
>             Any comments, info, or advice would be appreciated greatly,
> as I'm stumbling around in the dark on this one.  Of course I find I do
> that a lot in life anyway.

Schorl is probably a good choice as the black tourmaline is generally
available in almost any size needed and will generally take a good
polish.

Another common choice is hematite for a black stone, but it tends to be
a silver black.

An uncommon choice you might consider is uvite. Black uvite is found in
NY and crystals to an inch are not uncommon. Its a better black than
schorl.

Other uncommon choices are some of the ores like sphalerite that come in
black, or black minerals like augite, melanite, neptunite, rutile, or a
very dark smoky quartz. They all will take a polish.

You might also consider a black obsidian (instead of the translucent
apache tear).

Have fun!

Kreigh

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Message:05

Subject: Re: Issue No. 218 - faceting a black stone
Date: Thu, 02 Oct 2003 22:22:43 -0700
To: LapidaryArtsDigest <lapidary@caprock-spur.com>
From: Noel Rowe <noel@roughtocut.com>

Hi Todd,

Regarding faceting a black stone. Why not just facet some onyx. It's
opaque so lighting up the edges won't be a problem 7 it's certainly
black enough to qualify.

--
Noel Rowe
Rough To Cut
http://www.roughtocut.com

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Message:06

Subject: Solid Black Facet Rough?
Date: Thu, 2 Oct 2003 22:29:25 -0700 (PDT)
To: faceters@caprock-spur.com
From: Alan Sutton <alan923@yahoo.com>

     For Todd or others interested in "Black Facet Rough" I can say
that the best material I have found is Black Spinel. Spinel is fairly
hard, 8 on the Mohs scale I believe so should stand up to some wear. I
came into possession of some of this material a few years ago and spent
quite some time trying to verify that what I had was indeed Black
Spinel which I had never heard of before. I have since convinced myself
that it is. But I can make no guarantee.
     I cut a beautiful ECED 1.2 11X9 at 5.5C to try it out.  It is jet
black and was a pleasure to cut and the polish is beautiful. I think I
polished it with 50K on tin. The rough has a lot of crazing on it so I
tumbled it to remove the outer surface. The crazes are not very deep
and in no way affect the finished stone. The pieces are from 1-2Grams
up to 10-12Grams so should make some fairly good sized finished stones.
     I saw some stones of Black Spinel on the ACN cable channel a
couple of weeks ago. They were mostly smallish (1-2C) and of course
foreigh cut. Priced right though at about $10-$12/C.
     Alan Sutton

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Message:07

Subject: Re: black faceted stones
Date: Thu, 02 Oct 2003 22:44:13 -0700
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: Don Rogers <Don@Campbell-gemstones.com>

>     Any comments, info, or advice would be appreciated greatly,
>as I'm stumbling around in the dark on this one.  Of course I find I do
>that a lot in life anyway.

A year or so back, the GIA ran a piece in their Gems and Gemology on black
stones.  Basically if it is black and has a surface that reflects light
well, one stone is as good as another as even a good Gemologist will have
trouble telling one from the other.

Wear issues should be considered though for a piece used in jewelry.  IE
Jet is not as good a choice as Black Jade.  A black Diamond has higher wear
stamina than either the Jade or Jet.  But from an appearance point of view
there is little difference between them.  Included is "Black Onyx" which is
dyed agate, Black Tourmaline, which is really very dark green,  Neptonite
which is really very dark red,  Even crystal Azurite looks black but is
very dark blue.  There is even a local stone that I find on the beach that
polishes up very nicely.  What is it?  I haven't a clue, and it doesn't
matter as it looks like the rest of the black stones.  I call it Avalia
Beachite.  Black sapphires are usually a very dark brown, not really
black.  There is Black Spinel which was used a lot in faceted stones back
in the 50's and 60's.  You almost never see it anymore.  I picked up some
black spinel rough some year back when in Australia.  I have yet to cut
any.   There is black Diopside which is very soft.  There are the star
garnets from Idaho that look black on the surface, but are really a dark
red/orange.  I'm sure I'm missing some.  Oh yes, Hematite,  or Bloodstone
as it is called in Europe.  Iron Oxide which stains everything red when
cutting it.  Made that mistake once.

The key thing with any black stone is to get one that is free of any cracks
or soft spots.  These will show up very badly when polished.  The cracks
will pack in polish and turn white.  The soft area will look very dull.  If
you are going to try a "black onyx" you should be prepared to re-treat it
after cutting because the black is only "skin deep", the white core looks
really bad when exposed.

If I'm replacing a missing or damaged stone, I will use black jade if
possible.  Following that, I will use a "black onyx" of very close to the
size I need so I don't cut through the skin.

If it will polish out black on the surface, one is as good as the
next.  When faceting a solid black stone, there is no need to worry about
angles.  Just pick a set that gives a good "Face".  There is no need for a
pavilion as it cant be seen anyway and adds nothing to the stone other than
weight.

Don

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Message:08

Subject: Faceted black gemstones
Date: Fri, 03 Oct 2003 12:20:22 +0000
To: faceters@caprock-spur.com
From: denney.wilson@att.net

     Several points.  First, there is natural black sapphire - it is usually
called just corundum or emory.  You can possibly get it from a cabbing supply
company - it does make nice cabs.  There is no demand for this so that is why
synthetic is not usually offered.  As to other choices, you might, if you are
not successful with the tourmaline, try some of the really dard smokey quartz
pieces.  I have cut one that was nearly coal black and looked good.  Other
choices are black glass (see a craft shop for this), some obsidians, jet, or
some closed c axis tourmaline (with very careful cutting).  Good luck.

Denney L. Wilson
Wilson Lapidary

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Message:09

Subject: Black Rough.
Date: Fri, 3 Oct 2003 08:56:12 -0400 (EDT)
To: faceters@caprock-spur.com
From: dojac@webtv.net (Jack Denne)

Have you a source for black onyx? I have used it for Opal doublets. Had
a ring with a crest on black onyx.  

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Message:10

Subject: Issue no. 218
Date: Fri, 3 Oct 2003 12:28:27 +0300
To: <faceters@caprock-spur.com>
From: "birdamlasu" <fob@birdamlasu.com>

Subject: Solid Black Facet Rough?

Hello Todd,

Have you thought of jet for faceting? I haven't tried it for faceting
but in my country around Erzurum city, jewels are full of them.

You can see the stone in my web page
http://www.birdamlasu.com/mycountry
click on Gemstones of Turkey or Oltu stone of Erzurum
Good luck..

Hello Arch,

>1.  what the bow tie effect is<

     A dark area that you see in the middle of a pear, marquise or oval
stone which looks like a bow tie or a butterfly.

>2. why it is bad (or undesirable)<

   It is bad because in coloured stones you see a darkness in the middle
of the stone instead of colour and in diamonds it shows a dark area
instead of colourless bright area. The larger it is the less attractive
the stone is.

>3. what aspect of a cutting design causes "bow tie" i.e. what aspects
should be avoided. (e.g. is it more prevalent in centre-point designs or

designs with a keel).<

   If the pavillon is too deep or too shallow or the stone has long
culet these causes the bowtie effect.

Kind regards from Turkey,
Oya Borahan

PS; Dear Thurmond,
Thank you a lot  for the funnies at the end of each digest, we need
them. I send them to my children ones in a while. It helps to shorten
the distance between us. (My three children are all over the world. You
can see them in my website in the gallery page.)

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Message:11

Subject: Re: Bow Ties and Barions
Date: Thu, 2 Oct 2003 23:24:08 -0400
To: lapidary@caprock-spur.com (LapidaryArtsDigest)
From: Dan Clayton <dclayton@speakeasy.net>

On Thursday 02 October 2003 10:14 pm, Arch wrote:
> 1.  what the bow tie effect is
> 2. why it is bad (or undesirable)
> 3. what aspect of a cutting design causes "bow tie" i.e. what aspects
> should be avoided. (e.g. is it more prevalent in centre-point designs or
> designs with a keel).

Hi again Arch,

Bow Tie effect in ovals is when either the end or middle of the oval is
bright but not both. It is caused by the difference in angle between
facets going from end of oval to culet from those going from middle
of the oval to culet. It gets worse as the L/W ratio gets higher. That
is the oval gets longer and narrower. This is one of the main reasons
people design and cut barions and similar things like OMNI and
Breakpoint. Using a keel can also help. Check Bob Keller's very
good article on Bob's Rockshop at:

http://www.rockhounds.com/rockshop/gem_designs/bow_tie_blues/

Cutting the halfmoon break facets makes it possible to have angle
the same or very close for end and central facets. That halfmoon
facets themselves take up such a little small percentage of the
area under the crown that they do not degrade the optics.
BTW some OMNI and Breakpoint ovals are Barions and some are
just similar. That is according to Bob Long and Norm Steele. For
my money they wrote the book on Barions and you can still find it.

DC

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Message:12

Subject: What is a Gemstone??
Date: Thu, 2 Oct 2003 21:05:02 -0700
To: <lapidary@caprock-spur.com>
From: "Galarneau's" <gggemswcr@cox.net>

All,
  I have been involved in this business of lapidary since 1978. Lately I
have lost confidence in my own ability to define a gemstone.  Many
people I have talked to say that if something can be made into jewelry,
cut and polished, or just is pretty it is a gemstone.  Man-made,
organic, mineral, fossil, or resin they are all gemstones.  Pearls,
pectolites, amber, tourmaline, garnet, name them all the jewelry
industry says they are all gemstones..   Can anyone define a gemstone?

  Gerry Galarneau - In partly cloudy, cooling off Arizona, hopefully the
last triple digit day was yesterday for this year. Cutting lots of
Exotica Jasper, Picasso Marble, Botswana Agate, Crinoid Marble, garnets,
etc..the list never ends.  Gemstones???

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TODAY'S FUNNY ~

Reaching the end of a job interview, the Human Resources
Person asked the young MBA fresh out of MIT, "And what
starting salary were you looking for?"

The candidate said, "In the neighborhood of $125,000 a
year, depending on the benefits package."

The HR Person said, "Well, what would you say to a package
of 5-weeks vacation, 14 paid holidays, full medical and dental,
company matching retirement fund to 50% of salary, and a
company car leased every 2 years - say, a red Corvette?"

The Engineer sat up straight and said, "Wow!!! Are you kidding?"

And the HR Person said, "Certainly, ...but you started it."

   
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