This figure exhibits a combination occurring on the ferro-magnesian meta-silicate, Hypersthene. Forms: (a), (b), (m), (n), (h), (o), (c), (i), and (u).

Hypersthene

This figure exhibits a combination occurring on the ferro-magnesian meta-silicate, Hypersthene. Forms:…

Orthorhombic Iron Disulphide (Marcasite) sometimes shows cyclic groups of five individuals, bounded by ∞ P, {110} (M); P∞̆, {011} (l); and 0P, {001}, and united into a pentagonal figure by (M) as twinning plane.

Marcasite

Orthorhombic Iron Disulphide (Marcasite) sometimes shows cyclic groups of five individuals, bounded…