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Ca2B6O11·5H2O A colorless or white hydrated borate mineral that crystallizes in the monoclinic system and occurs in massive crystals or as nodules in clay.



(named for W. T. Coleman, 1824–93, the owner of the mine where it was discovered), a mineral of the class of borates. In terms of chemical composition it is a hydrous calcium borate, Ca[B2BO4(OH)3].H2O. Complex chains composed of B(O, OH)4 tetrahedrons and BO3 triangles bonded into a three-dimensional structure through Ca2+ ions and H2O buffer molecules are present in the crystal structure. Colemanite crystallizes in a monoclinic system, forming short, colorless crystals of columnar or dipyramidal appearance, as well as continuous fine-grained masses. Hardness on the mineralogical scale, 4–4.5; density, 2,440–2,450 kg/m3.

Colemanite is formed by precipitation, along with other borates (hydroboracite, inyoite, and borax), gypsum, and clayey deposits, from boron-containing brines of continental lakes. It is also found in the deposits of hot springs. Along with the other borates, colemanite is used as a boron ore.

References in periodicals archive ?
Piga, Arsenic Leaching by Na2S to Decontaminate Tailings Coming from Colemanite Processing, Miner Eng, 16 45 (2003).
Yartasi, A Semiempirical Kinetic Model for Dissolution of Colemanite in Aqueous CH3COOH Solutions, Industrial and Engineering Chemistry Research, 35(1996), No.
Eti Mine processes and markets the boron minerals commonly found in Turkey, namely tincal, colemanite and ulexite at the following facilities; Emet-Kutahya, Kirka-Eskisehir, Bandirma-Balikesir, Bigadic-Balikesir and Kestelek-Bursa.
The acquisition of Nordkalk will enable Ahlstrom to become a vertically-integrated manufacturer of glass fibre, as Nordkalk supplies raw materials used in glass fibre production - namely quick lime, kaolin and colemanite.
Dogan, Dissolution Kinetics of Colemanite in Oxalic Acid Solutions, Chem.
Recipes that are composed of saggar ash and ulexite are coded as A (uncalcined ash and ulexite) and AC (calcined saggar ash and ulexide); glaze recipes where colemanite is a flux are coded as B (raw ash and colemanite) and BC (calcined ash and colemanite); ash component stoneware recipes are coded as C (raw ash and stoneware glaze) and CC (calcined ash and stoneware glaze).
It operates two mines, both producing colemanite concentrates, grading [B.
The most important boron minerals of Turkey's are tincal, colemanite and ulexite.
Lustre Glaze Recipe I Lead Basilicate 20% Colemanite 6% Boric Aside 15% Potasium Feldspar 18% Flint 12% Soda 30% add: Silver Nitrate 1% Bizmush Subnitrate 1% Rutile 2% Tin Oxide 1% Lustre Glaze Recipe II Potasium Feldspar 33% Borax 37% Whiting 11% Soda 6% Flint 11% add: Silver Nitrate 1% Bizmush Subnitrate 1%