Tennantite with Chalcocite

This small cabinet specimen of intermixed Tennantite with Chalcocite richly coating a vuggy Quartz veinstone matrix is from the famous Cook's Kitchen mine at Pool, between Redruth and Camborne in Cornwall, England.  Cook’s Kitchen began in 1815, the same year as the Battle of Waterloo and continued until 1897, producing tin, copper and arsenic.  The Tennantite and Chalcocite form sooty dark grey crystals with a matt to semi-metallic lustre, all exhibiting natural etching and not easy to distinguish from one another.  Careful examination of crystal faces is the key to differentiating them apart.