Katophorite

minerals

Formula: Na(NaCa)(Mg4Al)(Si7Al)O22(OH)2
Inosilicate (chain silicate), amphibole group
Specific gravity: 3.2 to 3.5
Hardness: 5
Colour: Black,dark green-black, bluish black
Environments:

Igneous environments
Metamorphic environments

Katophorite was defined as the katophorite group mineral with Fe and Al as the dominant elements in the C position in up until 1997. The katophorite group was redefined in 2012, renaming the Fe2+ and Al dominant member of the group ferro-katophorite. The name katophorite is now used for the Mg and Al dominant member of the group, which previously was named magnesiokatophorite (Mindat).

Katophorite occurs in alkalic volcanic and plutonic igneous rocks, and in blueschist facies jadeite rock. Associated minerals include arfvedsonite, aegirine, nepheline, eckermannite and chromite (HOM).

Localities

The type locality for katophorite is the Hpakant-Tawmaw Jade Tract, Hpakant Township, Mohnyin District, Kachin State, Myanmar.

At the Shields River basin, Montana, USA, katophorite is found in basic alkaline igneous rocks forming rims on aegirine (Webmin).

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