Geocronite-Jordanite and Fluorite, Milpo Mine, Cerro de Pasco, Pasco, Peru

The January-February 2024 (volume 55) issue of the Mineralogical Record recently shed light on the black sulfosalts that were sharing the spotlight with beautiful green fluorite emerging from Peru. Along with bournonite, pyrite and galena are geocronite and jordanite; both lead-antimony-arsenic sulphides, but impossible to differentiate without chemical analysis. We have several specimens recently sourced several of these rare yet beautiful specimens from a good friend in Peru.

This is our largest and best specimen we are offering. This large specimen is richly covered, front and back, with silvery geocronite-jordanite crystals (and possibly bournonite) which has overgrown smaller brassy pyrite crystals. Emerald to apply green fluorite, in turn, has overgrown the geocronite-jordanite making for a nice colour contrast. Another side of the specimen has a curved, white crust (perhaps it once grew around another mineral long since dissolved?) and is now speckled with more sulfosalts and pyrite crystals. Very attractive, mineralogically complex and from the mysterious Andes Mountains!

From the Milpo Mine, Cerro de Pasco, Pasco, Peru. Dimensions: 7 cm x 7.5 cm x 10 cm