Millerite

A rare example of thickly-crystallised Millerite from Friedrich mine in the municipality of Mittelhof, Rhineland-Palatinate, Germany and ex. the Josef Clemente Collection of southern Germany.  Millerite, a nickel sulphide, typically forms delicate, hair-like acicular crystals but sometimes, like in this specimen, the crystals are broad and substantial, quite different to what we commonly see.  The Millerite forms crystals of about 1 mm broad (very wide for millerite!) and up to 2.5 cm long of a dull brass colour with a dull metallic lustre.  The acicular crystals lie flat against a core of reddish Feldspathic matrix, and richly cover all sides.  Please note this specimen does show micro-cracks through and across some surfaces, but these have remained unaltered in the specimen for a long time and from all we can ascertain it remains completely stable.  This specimen is ex. the Josef Clemente Collection (1899-1987) of southern Germany.