inosilicate (chain silicate), amphibole,
polymorph of grunerite
Hardness: 5½ to 6
Streak: White to greyish white
Colour: Clove-brown to dark brown, grey to white, pale green
The type locality is the Tamarack and Custer Mine, Placer Center Mining District, Shoshone county, Idaho, USA, which is hosted in quartzite (Mindat).
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