Argentite

ARGENTITE (from the Latin word "argentum" (silver) * EN: argentite, silver glance, vitreous silver argyrite; DE: Argentit; FR: argentite, argyrose; ES: argentita, argirosa; RU: аргентит) is the mineral of the class of sulphides, the cubic polymorphic modification of Ag2S, which is stable at the temperature of more than 173 degrees Celsius (below this temperature it transitions to acanthite). It is rare within the nature, the name "argentite" is often used for the paramorphs of acanthite, which are similar to argentite.