Franklinite on Calcite

An 18 mm long perfectly formed octahedral/bipyramidal black Franklinite crystal embedded in Calcite from the Franklin Mining District, Sussex County, New Jersey, USA. The abundance of Franklinite in the orebodies in the Franklin Mining District sometimes makes us forget how rare a species it is on a world scale. Even with this abundance, good individual crystals are uncommon and good crystals attached to matrix rarer still. This miniature specimen is a lovely example with the perfect black Franklinite crystal contrasting with the bright white Calcite matrix for dramatic effect.