Hi,
Chrysocolla to mineralogists is a secondary copper mineral - a hydrated
copper silicate; the name comes from the Greek for gold and glue, hence its
association with borax; not entirely sure WHY the secondary copper mineral
was/is called chrysocolla though.
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I believe that powdered chrysocolla is(was) made into a paste, and is(was)
used to support fine gold-work when undergoing hot welding (gold will weld
at room temperature too). At least, so an old goldsmith once told me.
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From: James Fussell <[log in to unmask]>
To: mining history forum <[log in to unmask]>
Subject: re. borax
Date: 03 April 2000 22:28
more about of borax:
Uses of borax/other borates/boric acid:
fluxes for manufacture of artificial gems, glasses and enamels, especially
in pottery and enamelled iron trades (is there still an enamelled iron
trade?)
used in soap and glue industries and in cloth manufacture and tanning
preservatives
antiseptics
paint-driers (?)
boron carbide, produced in electric furnace - near as hard as diamond -
used as abrasive and 'resistant material'
and last (for the moment) but not least - borax is used in the borax bead
test - qualitative chemical analysis for iron, copper, chromium, manganese,
cobalt, nickel and uranium; testing can be done miles from anywhere as long
as you've got a platinum wire (or at a pinch you can use the filament from
an electric light bulb - if there's one handy), a candle or spirit lamp or
something like that, and a blowpipe plus the breathing technique required
to use it.
"(Borax) has been obtained since early times from the salt lakes of Kashmir
and Tibet; it was brought to Europe as crude material called tincal and
then purified. [then several US localities in California and Nevada] Named
borax from the Arabic buraq, which included also the niter" [or nitre,
depending on which side of the Atlantic one comes from] "(sodium carbonate)
of ancient writers, the natron of the Egyptians. Borax was called
chrysocolla by Agricola because used in soldering gold." [Dana's Textbook
of Mineralogy, 4th edn, ed. W E Ford, 1932]
Chrysocolla to mineralogists is a secondary copper mineral - a hydrated
copper silicate; the name comes from the Greek for gold and glue, hence its
association with borax; not entirely sure WHY the secondary copper mineral
was/is called chrysocolla though.
Native boric acid (sassoline or sassolite) is or was exploited in Tuscany;
don't know when that started.
James
[log in to unmask]
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