This is a superb old-time European silver sulphide, magnificent in its crystallization. Miniature in size, the Acanthite crystals are incredibly prominent forming stacked, repeatedly twinned octahedral crystals, displaying a metallic grey appearance. Acanthite is technically monoclinic (bladed) in form but its polymorph Argentite is isometric (cubic). However, Argentite does not exist at below 177 C at atmospheric pressure - the internal form being replaced, or pseudomorphed, perfectly by Acanthite. The largest crystal here measures an impressive 1 cm across and in combination with the others forms an arborescent array in several crystal branches. It is from the important historic silver-mining district of Freiberg in Saxony, Germany. A stunning miniature specimen of rich silver ore with fine crystals. A green Richard W. Barstow sales label dating to pre-1982 accompanies this specimen.
