[Sca-cooks] Soapstone Re: Lemon syrup.
phelpsd at gate.net
Fri Jun 15 17:27:29 PDT 2007
If I have the right of it, talc is hydrous magnesium silicate, which is
deposited by sedimentation or hydrothermal injection. Talc is also used to
describe the softest form of soapstone, a metamorphic rock consisting mainly
of magnesium silicate with varying amounts and kinds of chlorite. Talc has
a Moh's hardness of 1. Soapstone has a Moh's hardness varying between 1 and
3. Steatite is more commonly used to describe the harder varieties of
soapstone which are used as countertops and heat sinks.
Hmmm... I was quoting, in the main from a rather old dog eared copy of
Dana's Mineralogy. Per Dana, "...talc is a secondary mineral formed by the
alteration of magnesium silicates, such as olivine, pyroxenes, and
amphiboles, and may be found as pseudomorphs after these minerals.
Characteristically in low-grade metamorphic rocks, where, in massive form,
soapstone, it may make up nearly the entire rock mass. It may also occur as
a prominent constituent in the schistose rocks, as in talc schist.
In the United States many talc or soapstone quarries are located along the
line of the Appalachian Mountains from Vermont to Georgia. The major
producing states are California, North Carolina, Texas, and Georgia."
Talc is of course a mineral while soapstone is a rock. As such soapstone is
typically an admixture of several minerals with talc predominating. I can
try and provide old world locations if anyone is interested.
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