The silver-rich zinc-lead sulfide deposit of Harmsarvet, 14 km NW of the famous ore deposits of Falun, south central Sweden, is located in a series of Precambrian biotite gneisses, about 2 km SE of a monzonite intrusion. Host rock to the mineralisation has undergone hydrothermal alteration, with especially sericitisation and saussuritisation on a large scale. The silver minerals are native silver, acanthite and silver-antimony-sulfosalts with an important part of the silver present as submicroscopic inclusions in secondary pyrite formed at the expense of pyrrhotite. On average, ore contains 0.39% Ag. A temperature of at least 177°C is proposed for the formation of the major part of the mineralisation.