Date: Tue, 12 Nov 2002 22:07:05 +1300
Reply-To: Conchologists of America List <CONCH-L@LISTSERV.UGA.EDU>
Sender: Conchologists of America List <CONCH-L@LISTSERV.UGA.EDU>
From: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject: Re: Glass disease clarification
In-Reply-To: <005501c2897d$09aac8e0$d0f0aec7@Jacobs>
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clarification</title></head><body>
<blockquote type="cite" cite>OK, I had to ask: What is glass
disease; what are the symptoms? I thought<br>
glass was inert.<br>
<br>
John Jacobs<br>
Seffner, Florida<br>
johncheryl@earthlink.net</blockquote>
<div><br></div>
<blockquote type="cite" cite><font color="#8080C0"><b>OK, now since I
do not understand the different kinds of glass, can you tell me if you
believe I am at risk of glass disease with shells in glass lamps,
glass jars from places such as Walmart,
etc... How
would I know if I had soda glass? Is the glass that
causes the disease<u><i> ONLY </i></u> the expensive tubes?<br>
Thanks!<br>
Mary Jo</b></font></blockquote>
<div><br></div>
<blockquote type="cite" cite>For all who are curious about glass
disease<br>
<br>
<br>
Glass Disease:<br>
<br>
A durability defect of glass,
leading to disintegration, due to a<br>
wrong balance of oxides and is unusually high in alkali or low
in lime.<br>
It is characterized by surface moisture and dulling, and
crizzling.<br>
<br>
More info can be found at:<br>
<br>
http://216.239.37.100/search?q=cache:qUzEeTvFeB8C:nautarch.tamu.edu/c<span
></span
>lass/anth605/File5.htm+%22Glass+Disease%22&hl=en&ie=UTF-8<br>
<br>
Basically, glass disease is a breakdown of glass. It forms
alkaline<br>
substances and leaves a hazy, powdery residue. If anything, it should
not<br>
cause concern about the condition of shell material. Remember,
Bynesian<br>
Decay (Byne's Disease) is due to acidic deteriorization of shells
(CaCO3).<br>
Glass disease results in alkaline materials and should not harm the
shell.<br>
I believe soda-lime glass (flint glass) is most at risk and the
more<br>
expensive borosilicate glass is less at risk. You can determine
which<br>
glass you have with UV light. Soda-lime glass fluoresces a
yellow-green,<br>
borosilicate glass does not. Paul Callomon, from the Academy of
natural<br>
sciences (philadelphia) presented a nice talk on this at the
American<br>
malacological Society Meeting this year. I will check my notes to see
if I</blockquote>
<blockquote type="cite" cite>left any details out.</blockquote>
<div><br></div>
<div>We are talking here about chemicals in the glass causing the
SHELL to break down, not the glass itself deteriorating. Shells can
become reduced to a white powder. My affected specimens have not
broken down yet, but are solidly encrusted by 2 different types of
crystals, and cannot possibly be cleaned... unless an ultrasonic bath
could do it.</div>
<div><br></div>
<div>Glass is not inert. In fact quite a few "standard"
chemical reactions do NOT take place unless a glass test-tube is
used!</div>
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