For all who are curious about glass disease


Glass Disease:

       A durability defect of glass, leading to disintegration, due to a
wrong balance of oxides and is unusually high in alkali or low  in lime.
It is characterized by surface moisture and dulling, and crizzling.

More info can be found at:

http://216.239.37.100/search?q=cache:qUzEeTvFeB8C:nautarch.tamu.edu/class/anth605/File5.htm+%22Glass+Disease%22&hl=en&ie=UTF-8

Basically, glass disease is a breakdown of glass. It forms alkaline
substances and leaves a hazy, powdery residue. If anything, it should not
cause concern about the condition of shell material. Remember, Bynesian
Decay (Byne's Disease) is due to acidic deteriorization of shells (CaCO3).
Glass disease results in alkaline materials and should not harm the shell.
I believe soda-lime glass (flint glass) is most at risk and the more
expensive borosilicate glass is less at risk. You can determine which
glass you have with UV light. Soda-lime glass fluoresces a yellow-green,
borosilicate glass does not. Paul Callomon, from the Academy of natural
sciences (philadelphia) presented a nice talk on this at the American
malacological Society Meeting this year. I will check my notes to see if I
left any details out.
  Hope this helps.
 Regards, Charlie
******************************************************************************
Charlie Sturm, Jr
Research Associate - Section of Mollusks
                     Carnegie Museum of Natural History
                     Pittsburgh, PA, USA

Assistant Professor - Family Medicine

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