Grouped parallel-growth crystals of acanthite (pseudomorphs after argentite) with wires of silver perched on and around the acanthite. The largest silver wire is 0.5 cm. Some of the silver wires have some associated acanthite – it is hard to know if these are minor coatings or more in the nature of partial replacement, but some of the silver is certainly not replaced on this specimen (unlike some others where it seems to have been entirely replaced. In very good condition, the lowest of the top three acanthite tips has a nick, and otherwise no damage. Very neat association piece with good-sized acanthites.
About These Acanthites
Well-crystallized acanthite has never been common and most of the known localities for crystals are historic, making it difficult, and usually expensive, to obtain fine specimens. The finds at Imiter (Africa’s largest silver mine) in recent years have placed it among the world’s best localities for crystallized acanthite. Although these crystals formed as argentite, argentite is not stable below 179C, at which point it changes to monoclinic acanthite. The specimens are acanthite pseudomorphs after argentite, retaining the isometric crystal form of the original argentite crystals. I assembled this lot of acanthites over a period of about two years. Most of these specimens, from the 2008 find, remained in Morocco until 2013.