Classic, old-time material from the famous mines at Cavnic, Romania. Lustrous, sharp, steel-gray tetrahedrite tetrahedrons to 2.2 cm cover the matrix of quartz and minor sphalerite. Ex. Hans Karabacek, Mitch Gunnell and Dr. Bob Byers Collections. Karabacek was a noted Austrian collector who lived from 1878 to 1963 and was known for collecting only the best of specimens. Accompanied by a handwritten Karabacek label. Rich and excellent material with a great provenance. The Karabacek collection mostly ended up in Harvard and pieces today are seldom seen for sale.