Janggunite

Janggunite
General
Category Oxide mineral
Formula
(repeating unit)
Mn5-x(Mn,Fe)1+xO8(OH)6
Strunz classification 4.FG.05
Crystal system Orthorhombic
Unknown space group
Unit cell a = 9.324, b =14.05
c = 7.956 [Å], Z = 4
Identification
Color Black
Cleavage Perfect,one direction
Tenacity Fragile
Mohs scale hardness 2 - 3
Luster Dull
Streak Brownish black to dark brown
Specific gravity 3.59
Optical properties Biaxial
References [1][2][3]

Janggunite is a rare manganese oxide mineral with formula Mn5-x(Mn,Fe)1+xO8(OH)6.

It was first described in 1976 for an occurrence in the Janggun mine, Bonghwa-gun, Gyeongsangbuk-do, South Korea and named for the locality.[2]

References

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