Gahnite (rare locality specimen)

Item Description

A hard to find Gahnite specimen from the great Broken Hill area in Australia. Gahnite is a member of Spinel group, and was defined for a time as a zinc-bearing Spinel, but it's actually a valid species, as it forms a series with Spinel were zinc substitutes for magnesium. I've also seen some manganese-bearing Gahnites from Langban, Sweden, but I don't know if any of the Broken Hill pieces contain manganese. This piece is a good representative example featuring black crystals measuring up to 6 mm, with minor tan Sericite, sitting on Quartz matrix, not the typical Calcite/marble that you would expect from Gahnite (or Spinel). A cool reference specimen that is not commonly seen in crystallized examples from Broken Hill.
From the collection of Gerry Morvell.