Freieslebenite Locality: Braunsdorf, Freiberg, Saxony, Germany Size: miniature, 5.6 x 4.4 x 1.9 cm Freieslebenite This beautiful little specimen features extremely sharp twinned Freieslebenite crystals to 4mm (as a cluster), perched on crystallized quartz matrix. It was once in the Museum of Bonn in Germany, and their label notes that they obtained it from the famous German dealers August Krantz (1809-1872) and his son, who lived in Bonn from 1850 on. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Freieslebenite
A silver-lead-antimony sulfosalt named for the Saxon mining commissioner Johann Karl Freiesleben.
Intro adapted from Wikipedia (CC BY-SA).
Freieslebenite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula AgPbSbS₃.
It crystallizes in the monoclinic crystal system (space group P2_1/a).
Key properties: Mohs hardness 2–2.5; specific gravity 6.2–6.23; Pale steel-gray to silver-white or lead-gray streak; Metallic luster.
IMA symbol Flb, grandfathered status — known before the IMA’s founding, named in 1845.
Hydrothermal in origin.
It is found associated with Acanthite, pyrargyrite, silver, andorite, galena, siderite.
The mineral was named to honor Johann Karl Freiesleben (1774–1846), Mining Commissioner of Saxony, Germany, who first described the mineral.