Images
Formula: Ca[B5O8(OH)][B(OH)3].3H2O
Hydrated borate containing hydroxyl
Crystal System: Monoclinic
Specific gravity: 2.00 measured, 2.003 calculated
Hardness: 3
Streak: White
Colour: Colourless, white
Luminescence: Not fluorescent under UV
Environments
Volcanic igneous environments
Evaporite deposits
Localities
The type locality is the Hard Scramble claim, Ryan, Furnace Creek Mining District, Inyo county, California, USA.
Gowerite has been found at four localities in the Furnace Creek borate deposits. It was first found at the Mott
open cut, but it is more abundant on the Hard Scramble claim.
At the gowerite localities, colemanite and
priceite veins, generally less than 2 inches thick, occur in altered fragmented
olivine basalt. The
borate-veined basalt is in the
Furnace Creek formation and lies above the main zone of colemanite and
ulexite, which is in lake and stream sediments near the base of the formation.
The gowerite is restricted to a weathered zone where the colemanite
and priceite veins waste away within a few feet of the present surface of the
hillsides and leave irregular aggregates of alteration products. Among these products of weathering at many localities,
gowerite is one of the rarer borates, like
sassolite and hydroboracite, in
contrast to consistently abundant fluffy ulexite. Others, such as
ginorite, meyerhofferite,
colemanite and a magnesium borate of
uncertain identity, seem to be intermediate in abundance.
Associated minerals include gypsum,
thénardite and some limonite.
In the Mott open cut some of the scarce gowerite is in globular clusters, to 10 mm in diameter, of radiating small
blades on remnants of a colemanite vein, and closely associated with crusts
and clusters of subhedral crystals of meyerhofferite, some
gypsum, and a small quantity of
hydroboracite. Some of the gowerite at Mott forms small clusters
in the loose aggregate from the weathered basalt, like the much more
abundant ginorite associated with
sassolite nearer the surface. Ulexite
occurs throughout the weathered zone but is concentrated in the upper part.
The more abundant gowerite at the Hard Scramble locality is in compact globular clusters, commonly from 1 to 10 mm
in diameter, within loose material weathered from the underlying basaltic
rock and on vein-like coherent aggregates of meyerhofferite, also
produced by the weathering of the priceite veins.
Ulexite, ginorite and
gypsum occur with the gowerite but are more widely distributed in the
weathered material above the veins. Unlike those at the Mott locality, the alteration products at the Hard Scramble are
derived from priceite, and no
sassolite was found among them
(AM 44.911-919).
Back to Minerals