Beautiful specimen of sharp Sphalerite tetrahedrons with Quartz and Calcite from the famous Madan ore field, Bulgaria. On small spiky Quartz crystals grow black Sphalerite tetrahedrons with strong luster. The crystals show penetration twinning. They are chunky, sharp, well isolated and shiny. The tips are truncated. Come colorless Calcite is seen too. In good condition – some nicks and contacts.

Fantastic!