Calcite

The Banana Slide was a richly mineralised fault zone at 400 m depth, extending some 1.6 km to the east of Egremont and could be accessed from several adjacent mines.  This specimen is from Haile Moor mine near Egremont and based solely on the habit, size, colour and lustre of the Calcite crystals, this could be from no where else, a Banana Slide classic!  Interestingly, the Calcite habit gradually changed traversing along Banana Slide, with large nail-head crystals such as these at one end and fine, almost acicular scalenohedral crystals at the opposite end.  The entire fault zone was richly crystallised and miners would work in their spare time extracting the crystals to sell.  This spectacular specimen comprises of approximately ten tightly packed adjacent crystals, all of nail-head habit with trigonal, Mercedes-type flattened pyramidal terminations.  The terminations are of quite transparent colourless Calcite, have vertically orientated fine striations and grade to brick-red prisms coloured by finely disseminated Hematite inclusions. The terminations, viewed with a x5 loupe, contain delicately-structured plumes of a black mineral, most likely manganese.  Amongst the crystals is single deep cavity, seemingly where a crystal should have developed, but obviously did not.  This is a wonderful nail-head Calcite from the evocatively named Banana Slide Fault Zone in West Cumbria.