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A member of the alkali amphiboles with the composition (Na,K)Ca2(Mg,Fe)4Ti[Si6Al2O22](OH)2 in a group which includes katophorite Na(Na,Ca)(Mg,Fe2+)4Fe3+[Si7AlO22] (OH)2 and oxyhornblende NaCa2(Mg,Fe, Fe3+,Al,Ti)5[Si6Al2O22](OH,O)2; sp. gr. 3.2–3.5; hardness 5.0–6.0; small euhedral crystals; dark brown to black; this rare group of amphiboles occurs in intermediate alkali igneous rocks.

Subjects: Earth Sciences and Geography.

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