A cluster of lustrous metallic grey-black crystals perched on Acanthite. It is possible that many (most) are twinned as is characteristic for the species, from what we have been told. A very rare member of the silver species group! This is a shockingly bright and sparkling specimen with highest luster. From Marshall Sussman (Crystal Cellar, Oro Valley, Arizona) on March 5, 2019. Photo by Tom Spann. Photos of this specimen can be found in: The Mineralogical Record, Arizona Mineral Collections, 2020; 55(1): 156.