Tiemannite is a very rare mercury selenide: simply HgSe. This is the classic locality for crystals: tiny black modified tetrahedra. This specimen hosts a few very choice, sharp crystals, unusually free of alteration coatings, on matrix. The crysta; ls are small, under 2mm, but very sharp and eye-visible. Another vug, with smaller crystals, lays beneath them. One suspects the museum numbering person mislabeled the piece, not recognizing the material and putting the museum accession number on the display face!