Glass beads

I am researching a number of late 19th century black dyed silk
textiles which have degrading (formation of white crystals,
crizzling and weeping) black glass beads.  I have access to
facilities to analyse the glass but can not easily identify the dyes
used. Could anyone suggest likely dyes and finishes for this period?
>From the published literature the degradation of black glass beads
on black textiles form the late 19th century seems to be quite
common, is this just a coincidence or have other people also
observed more glass decay on black textiles than other colours?


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                  Conservation DistList Instance 15:62
                  Distributed: Tuesday, March 12, 2002
                       Message Id: cdl-15-62-018
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