Mindat Short Description

The magnesium-iron-manganese subgroup amphiboles are defined with Mg, Fe or Mn as the dominant element in the B position, or B(Ca + ΣM2+)/ΣB ≥ 0.75, BΣM2+/ΣB > BCa/ΣB, where M is Mg, Fe and Mn.

This subgroup contains both monoclinic (cummingtonite a...