Iron Cap Mine, Landsman Camp (Landsman group), Aravaipa, Santa Teresa Mts, Aravaipa District, Graham Co., Arizona, USA

CaFeSi₂O₆

Crystal System: monoclinic
Colour: brownish green or black
Lustre: vitreous, dull
Habitus: prismatic to fibrous
Hardness: 5½ - 6½
Fracture: irregular/uneven or conchoidal
Cleavage: distinct/good on {110}
Density: 3.65 g/cm³ 
Origin and geological occurrence: it belongs to the pyroxene group. Hedenbergite is a common constituent of metamorphosed iron formations or other ferruginous siliceous sediments and in Fe-Mn skarns.

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Samples:

9D.4 Hedenbergite  Fibrous crystals with quartz. Campiglia Marittima, Livorno, Tuscany, Italy. #inosilicates