Colemanite from Boron, California, USA - image 1
Colemanite from Boron, California, USA - image 2

Colemanite from Boron, California, USA

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Colorless bladed crystals of colemanite to 3.0 cm in size on matrix. In good condition.The Boron deposit, located in the Kramer borate district of Kern County, California, has a history dating back to its discovery in the early twentieth century, growing into one of the world's largest sources of boron-bearing minerals. Geologically, the deposit is hosted within Miocene-aged lacustrine sedimentary rocks of the Tropico Group, filling a structural basin associated with volcanic activity. The borates formed through the evaporation of boron-rich thermal and mineral springs in a closed lake basin. While the primary economic mineral of the massive deposit is sodium borate (kernite and borax), the surrounding and earlier-formed zones are well known for producing magnificent, highly modified monoclinic crystals of colemanite, a hydrated calcium borate formed through secondary alteration and crystallization processes.

Product details

SpeciesColemanite
SizeSmall Cabinet
Dimensions8.0 x 6.0 x 3.5 cm
Added on07/29/2026
LocalityUSA, California, Boron
Current owner
Unknown Owner
Acquired
Aug 2026
Previous owners
DateCollectorAcquisition price
—Weinrich MineralsNot disclosed

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Colemanite
Mineral guide
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Colemanite
Regional guide
Colemanite from Boron
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Locality guide
Boron
Boron, USA - Kramer borate deposit, a Miocene evaporite system yielding colemanite blades, ulexite, borax, kernite; renowned for mineral variety and paragenesi…