It comes from the famous mining district of Baia Sprie (Felsőbánya/Kapnikbánya in German) in Transylvania, Romania, where it has been mined since the 19th century along with silver, lead, and zinc. The Transylvanian deposits, of hydrothermal-epithermal origin associated with Tertiary volcanism in the Carpathian Mountains, have yielded some of the world’s most famous museum specimens of antimonite, featuring long, slender, lustrous acicular prismatic crystals, often in radiating or interlaced groups. Lead-gray in color with a brilliant metallic luster, gray-black streak, low hardness (2 on the Mohs scale), density 4.6 g/cm³, and perfect cleavage parallel to the crystal’s elongation.

A specimen of great historical and museum value: the ancient Transylvanian specimens, collected between the 19th and early 20th centuries, are among the most sought-after and highly valued pieces by collectors of classic European minerals; highly prized for the elegance of its radiating crystal clusters;