3.0 x 2.0 x 1.5 cm. Silvery-gray, fan-shaped aggregates of acicular crystals of the rare sulfide eclarite on white quartz with chalcopyrite. Very good specimen from the type locality. Ex. Paulo Matioli collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Eclarite
Eclarite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula (Cu,Fe)Pb₉Bi₁₂S₂₈.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Kobellite structural group.
Key properties: Mohs hardness 2.5; specific gravity 6.85; Metallic luster.
IMA symbol Ecl, IMA status: approved, named in 1982.
Found in gold-bearing sulfide ores of copper located in quartz veins cutting amphibolite facies metamorphosed mafic rocks (Bärenbad, Austria).
It is found associated with Pyrite, arsenopyrite, chalcopyrite, pyrrhotite, sphalerite, stannite, bismuth, gold, quartz (Bärenbad, Austria).
The mineral was named to honor Professor Eberhard Clar (1904–), Austrian mineralogist, University of Vienna, Vienna, Austria.