Aguilarite is a rare Ag-Se sulfide, with the San Carlos Mine in the Guanajuato district being the Type Locality. This fine, sponge-like cluster consists of a myriad of intergrown, skeletal, pseudocubic crystals that are a metallic grey-green. There are possibly even some Acanthite crystals mixed in, which Aguilarite is isostructural with. Formally in the collection of rarities expert Bill Pinch. For what it is, this is a fine thumbnail, and the world's best Agularites have come from the historic silver mines at Guanajuato. Analysed in teh Downs lab at University of Arizona, Bill Pinch confirmed this himself some years ago. it comes with his label and an older Burminco label from the 1960s or 1970s. SUPERB specimen!