Rathite Locality: Lengenbach Quarry , Im Feld (Imfeld; Feld; Fäld), Binn Valley, Wallis (Valais) , Switzerland ( Locality at mindat.org ) Size: miniature, 3.9 x 3.3 x 1.8 cm Rathite (huge XL from type locale) This specimen hosts a HUGE crystal for the species, measuring 2.8 cm - over an inch long! It is up to 8mm width. The crystal face is complete and undamaged, and the crystal shows off its end-terminations at top and bottom. A major crystal for the species, of some importance, and well above anything you typically see from the locale. This is an older piece that has been in a private German collection for some time. I have not seen a larger example for sale. To be sure about it, i had this tested every which way by Bart Cannon's lab in Seattle, to prove to his satisfaction that it is rathite , and not the slightly more common lengenbachite or baumhauerite. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Rathite
Rathite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Ag₂Pb₁₂₋ₓTlₓ/₂As₁₈₊ₓ/₂S₄₀.
It crystallizes in the monoclinic crystal system (space group P2_1/a). It is a member of the Sartorite structural group.
Key properties: Mohs hardness 3; specific gravity 4.99–5.45; Chocolate-brown streak; Metallic to dull luster.
IMA symbol Rat, grandfathered status — known before the IMA’s founding, named in 1896.
Found in crystalline dolostone with other Pb-As-S minerals.
It is found associated with Liveingite, baumhauerite, sartorite, hutchinsonite, dufrénoysite, tennantite, pyrite.
The mineral was named to honor Gerhard von Rath (1830-1888), Professor of Mineralogy, Bonn, Germany.