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Colemanite

Specimen cases holding small mineral samples on a reference tray, viewed from above.

Properties

Property table of the Wikipedia article “Colemanite”, reprinted as recorded in the fetch.
CategoryInoborates
FormulaCa2B6O11·5H2O
Crystal systemMonoclinic
ColorColorless, white, yellowish, grey
Crystal habitMassive granular to coarsely crystalline, most commonly nodular.
Cleavageperfect, distinct
FractureBrittle uneven to subconchoidal
Mohs scale hardness4.5
LusterVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity2.42

From the Wikipedia article

Colemanite (Ca2B6O11·5H2O) or (CaB3O4(OH)3·H2O) is a borate mineral found in evaporite deposits of alkaline lacustrine environments. Colemanite is a secondary mineral that forms by alteration of borax and ulexite.

Source

Source record: crystal-compendium/colemanite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.

https://en.wikipedia.org/wiki/Colemanite — revision id 1346390802. Text and properties from Wikipedia, licensed CC BY-SA 4.0.