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Colemanite (2CaO·3B₂O₃·5H₂O)

Colemanite, or hydrated calcium borate (2CaO·3B₂O₃·5H₂O), is an important ore of boron. It is a colorless or white monoclinic stable borate mineral that is a common natural source of insoluble boron.
Typical Chemical Analysis

B₂O₃= 39.50 – 40.50%
CaO= 26.00 – 28.00%

Chemical and Physical Properties

• Melting Point: 930ºC
• Solubility in Water: 0.81% by weight @ 20ºC of a saturated solution
• pH: 9.5 (1.0% solution @ 20ºC)
• Approx. Bulk Density: 55 lbs/ftᶟ
• Decomposition: Dehydration begins 105ºC

Typical Applications

Colemanite is a naturally occurring, mineral borate product used in many different applications, including heat-resistant glass, glazes, enamels, cleaning products, roofing products, fiberglass, flame retardancy, steel making/slag modification and agriculture.

Packaging Options

Bulk 2,200 lb. super sack and in 25 kg net (55.2 lb. net) multiwall paper bags, and custom packaging


Colemanite TSCA (SARA Title III) Status: Listed. For further information, please call the E.P.A. at +1.202-554-1404.
Colemanite CAS Number: 1318-33-8
Colemanite EC Number: 296-640-5

U.S. National Library of Medicine (NIH): Substance Listing

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  • Powder (75 Microns)


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