20698: Ulexite replacing Borax - Was $50 Now $25
Boron Open Pit,
Boron, Kramer Borate deposit, Kern County, California
Small cabinet - 6.7 x 4.0 x 3.1 cm
74 grams
Specimen status: Available
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specimen number to order
Borax - Na2(B4O5)(OH)4·8H2O
is the dominant species mined at the U. S. Borax Open
Pit. However borax easily suffers chemical alteration,
resulting in replacement by the new species while the
borax crystal shape is preserved (i.e., pseudomorphed).
Dehydration to tincalconite - Na2(B4O7)·5H2O
is common (and is the general fate of borax specimens
unless very carefully preserved). Much less commonly
seen is alternation to fibrous, silky ulexite - NaCa[B5O6(OH)6]·5H2O.
This is due, in part, to the nonphotogenic nature of
these pseudomorphs; their homeliness caused them to be
often overlooked in the massive dumps. This example is
prettier and more distinctly shaped than most, as well
as being on the large size. Nothing I would consider to
be damage. A superb example for the collector of
borates, of pseudomorphs, or of California minerals. The
pit's dumps have been closed to collecting for years
now, so finding quality specimens from this locality is
becoming increasingly more difficult.
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