At 05:26 PM 12/13/00 -0500, Beverly Erlebacher wrote:
> > From: [EMAIL PROTECTED]
> > Date: Wed, 13 Dec 2000 17:09:33 -0500
> >
> > As of this writing, I
> > have a bottle that was purchased from City Chemical in NYC, The label
> says,
> > Zinc Sulphate and in parenthesis Pumice Powder!
>
>Wow, that's pretty strange. If pumice the natural rock were actually zinc
>sulphate, I'm sure the Canary Islands would have been mined to the water line
>for zinc! I've never heard of pumice as a common name for zinc sulphate, but
>they wouldn't print it on the label if it weren't true, eh?
In trying to resolve this matter by appeal to the Web, I found a whole
truckload of chemical supply sites that sell "pumice powder" and "zinc
sul[f|ph]ate" as two different products. Perhaps City Chemical extracts
its zinc sulphate from impurities in a particular batch of pumice, or
something?
On the Web site of a pumice supplier in Turkey
(<http://www.ekokim.com/Pumice.htm>) I find the following:
Pumice is a lightweight volcanic, sponge like aluminum
silicate rock of igneous origin with a porous structure
formed by a process of volcanism. This highly vesicular
volcanic stone consisting mainly of silica SiO2. The high
silica content (ca. 70%) positively affects the quality of
pumice increasing the hardness of the material and its
resistance to chemical attack.
Further along they give a chemical breakdown of the pumice they supply:
69.9% SiO2, 14.3-14.9% Al2O3, 1.6-3% Fe2O3, much smaller amounts of TiO2,
SO3, and MgO, and a bit of moisture. No mention of zinc.
Weird.
NT
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