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Formula: NaCaB5O7(OH)4.3H2O
Hydrated borate containing hydroxyl
Crystal System: Monoclinic
Specific gravity: 2.135 to 2.141 measured, 2.132 calculated
Hardness: 3½
Streak: White
Colour: Colourless, colourless in transmitted light
Solubility: Readily soluble in dilute acids. Partially decomposed in hot or cold water, with Na being leached relative
to Ca
(Mindat)
Environments
Probertite occurs in lake-bed deposits, the boron supplied by
hydrothermal
spring activity. Probertite may be an ore of boron. Associated minerals
include kernite, colemanite,
ulexite and borax
(HOM).
Localities
Doğanlar boreholes no. 2 and no. 188, Doğanlar village, Emet District, Kütahya Province, Turkey. Probertite
and glauberite are the main rock-forming minerals in the lacustrine
Doğanlar succession of the Emet basin. They are primary
products grown subaqueously in a relatively shallow saline lake
(Journal of Sedimentary Research 86.5.448–475).
At the type locality, the Baker Mine, U.S. Borax Mine, Kramer Borate deposit, Boron, Kern county, California, USA,
Probertite and kernite are the main
borates of the replacement deposit, and the crystallisation of the
probertite has preceded or has been simultaneous with the crystallisation of the
kernite. These two exceptional
borates
are evidently products of fumarolic or hot-spring conditions in which the temperature was the important factor
influencing
the crystallisation of these two lower hydrates, as the main minerals of the deposit, instead of the usual and common
borax and ulexite. The presence of
realgar, orpiment and
stibnite as associates of the
kernite
confirm this view of fumarolic action
(AM 14.427-430).
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