CR13AM4: Tetrahedral crystals of Tetrahedrite with epitaxic coatings of Chalcopyrite, very lustrous, on matrix and with small coatings of white rhombohedral Dolomite crystals.
Some crystals are fractured as is often the case in these classic pieces since it is an old German specimen referenced in mindat.org (Mindat ID: YYU-5K4). It comes from the collection of Carlos Curto (number 1970.13) whose label and computer catalogue entry we will send to the buyer.
Clausthal-Zellerfeld, Goslar District, Harz, Lower Saxony/Niedersachsen  Germany

Specimen size: 4.6 × 3.5 × 2 cm = 1.81” × 1.38” × 0.79”

Main crystal size: 0.9 × 0.8 cm = 0.35” × 0.31”