Calcite with Boulangerite

The resultant effect of micro-crystallised Calcite rhombs, jet-black due to Boulangerite inclusions and forming curved ridges, is a specimen with a texture and lustre of rippled, brushed silk.  This eye-catching and showy miniature is from Cavnic mine in Maramureș County, Romania.  Boulangerite is a lead antimony sulphide, normally classed as a sulphosalt and forms finely divided particles and acicular hair-like inclusions; in many instances turning the Calcite grey, but in this example, jet-black.