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. 36 Mon 7/28/97
2. NEW: Starting Out in Lapidary
3. RE: Starting Out in Lapidary
4. RE: Dangers of Rock Dust
5. AD: Liccini


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<MSG1>
Subject: LapDigest News for Issue No. 36 Mon 7/28/97

I am publishing another letter on lung damage from exposure to fresh cut
rock dust, as I believe this is a very important topic. This thread
refers to raw rock dust from dry cutting/grinding (without a fluid shield,
or a mask.) It does not refer directly to our usual cutting, grinding
or sanding operations, as we almost always (or should) have a fluid
shield, either water or oil, and frequently a mask.

However, in using either trim and slab saws, with either water or an
oil lubricant, I think it is still a very good idea to wear a mask. In
one 20 minute session on a 6" trim saw at Wildacres, my mask was
heavily spotted with small oil spots thrown out by the saw; without a
mask, these would have been inhaled right down into my lungs! And many of these small oil droplets COULD have contained a small piece of the cut material.

Be careful... you only have two lungs, and with two nostrils, they both
can get contaminated at the same time!
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<MSG2>
Date: Tue, 29 Jul 1997
From: mjones@gophone.com

Subject: NEW: Starting Out in Lapidary


Hi everyone. I am 38 yrs old and just starting out in rock/gem collecting
after a Bancroft, Ontario trip. I am really excited and welcome any tips or
suggestions as well are areas in Ontario that are great to work. I appreciate any info you can relate about neccessary equipment and where to begin in lapidary work. Thanks in advance! :]

Noria Jones
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<MSG3>
Date: Tue, 29 Jul 1997
From: hale2@mindspring.com

Subject: RE: Starting Out in Lapidary

Noria, and anyone else just starting out:

First, welcome to the Hobby. It is a wonderful way to be creative, to learn about rocks and minerals, and to meet some very nice people.

Advice? Find a good local club and join it. In Canada, there is a very good listing of all clubs in the Directory put out by the Rock and Mineral Association of Canada, whose URL is <<http://pangea.usask.ca/~dfs846/rmac/rmac.html>>. For clubs in the US, try Albert Zabinski's home page:<< http://bankswith.apollotrust.com/~zabinski/ , and in Australia, contact John G.Bowden at <<johnbow@onthenet.com.au>>, who will look up clubs for you in his listing.

If there are several clubs in your area, contact them all. Some clubs specialize in mineralogy while others are strong in lapidary. Many clubs give instruction in workshops or short courses in a variety of lapidary topics, at very low cost; they may have their own machines, letting you try out both lapidary topics and machines to see what you might be interested in. Also, I have found that club members like to help others - so ask questions of as many of the members as possible and assess their answers for yourself. Finally, many club members will have their own shops at home, with a wide variety of equipment. Try to visit their shops and discuss their equipment with them.

I know we have members who collect lapidary material in Canada each year, and I hope they will also respond about collection sites.

This should give you a good start... Oh, and keep reading LapDigest! (smile)!
-- non-commercial republish permission granted --
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<MSG4>
Date: Mon, 28 Jul 1997

Subject: RE: Dangers of Rock Dust


This is a continuation of the article on the dangers of rockdust. In the first letter, the writer said that he used a portable rock saw without a water shield or a mask, and had suffered considerable lung damage from
a one-time exposure, and warned everyone to 'mask up' ! The earlier postings on this topic are in Issue 30, #2 (written as 30-2), 31-4, 31-5, and 32-7.

(In an earlier post on Rocks-and-Fossils mail list, dated 7/16/97, someone had suggested that there were two reasons why freshly cut rock dust was far more dangerous then wind blown dust. First, it has sharper edges which can really damage your lungs; the comparison between them was compared to the differences between shards of broken glass and tumbled pebbles. Next, the concentration of rock saw dust is probably much greater than the concentration of dust in wind. )

In reply to this, on Thu, 17 Jul 1997 "Nathan A. Schachtman" <nschacht@voicenet.com> writes:

The reason is much more likely to be that freshly fractured silica carries a surface charge (high zeta potential) that makes the particles much more membranolytic or cytotoxic. It really has nothing to do with
the shape of the particle.

If you take those same particles and allow them to age, their biological activity goes down as the surfaces are hydrated. The toxicity of the particles can be restores by washing the particles in acid to dissolve away the layer of hydration (Beilby layer) and expose the fresh silica surface.

Someone else mentioned that silicic acid (silanols) was the bad acting chemical functionality. That's not at all clear. At neutral pHs, silicic acid is not going to much protonating. It is hydrophilic, and can be absorbed in bodily fluids and excreted. Indeed, silicic acid is how we absorb silicon as an essential neutrient. It is a normal constituent of connective tissues and bones, and most human organ tissues has a baseline of silicon content.

Amorphous silica is relatively harmless, and it has surface silanols as well.

The sort of fatal silicosis that results from short, extremely intense exposures is well known in the sandblasting industry. Sandblasting with silica has been prohibited in the UK for a long time now. I suspect
that we will see it outlawed within a year or so in the US.

Can fatal silicosis result from a single intense exposure. I would want to see the chest x-rays myself, but there are case reports of people inhaling extremely fine ground silica, such as you will find in Ajax type products, with lethal effects.

Nathan A. Schachtman

{Reprinted with permission of the author}
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<MSG5>
Date: Tue, 29 Jul 1997 11:54:23 -0400
To: <lapidary@mindspring.com>
From: mark@LICCINI.com
Subject: AD: Liccini


With great pleasure I would like to offer below an extra fine lot of
assorted Beryls I just received from customs.

http://www.LICCINI.com/July/BERYL.htm

In addition,I would like to further offer an extraordinary lot of huge
water clear hammered flawless Quartz.The sizes are 500gm to 2 kilo.Did you
ever want to facet that big one?Or seeking the material for that fine
carving?These make excellant stands also,or hey!Slice em,hinge em,and carve
out the centers to make a giant egg with that special item featured
inside.The smallest ones measure 4"x4"x4".the special price is
$150/kg($.03/ct).That makes a 500gm stone only $75.
*larger sizes available,discounts for volume purchase,inquire.

Leaving this week again for Brazil,but only for a week.Please send your
inquirys and orders with the word "order" in the subject.

Lastly,please check the following URL's for all newer top merchandise.

http://www.LICCINI.com/List/May.htm
http://www.LICCINI.com/June/JuneList.htm

Mark Liccini
LICCINI
Gemstone Rough Dealers since 1970 U.S.MAIL
E-Mail: mark@LICCINI.com 107 C.Columbus Dr.#1A
http://www.LICCINI.com Jersey City,N.J.07302
Voice Mail/Fax: 201-333-6332
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