Argentopolybasite

argentopolybasite

argentotetrahedrite-(Zn)

rozhdestvenskayaite-(Zn)

naumannite

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Formula: Ag16Sb2S11
Suphosalt, pearceite-polybasite group, antimony-bearing mineral
Crystal System: Trigonal
Specific gravity: 6.403 calculated
Hardness: 3
Colour: Dark grey to black
Environments

Volcanic igneous environments
Hydrothermal environments

Localities

There are two co-type localities, the Arykevaam deposit, Anadyrsky District, Chukotka Autonomous Okrug, Russia, and Šibeničný vrch, Nová Baňa, Žarnovica District, Banská Bystrica Region, Slovakia.

At the co-type locality Arykevaam deposit, Anadyrsky District, Chukotka Autonomous Okrug, Russia, the epithermal gold - silver deposit is located on the flank of a dome-shaped volcanic structure composed of various Upper Cretaceous (100.5 to 66 million years ago) volcanics ranging from basalts to subalkaline rhyolites. The outcrops of subvolcanic bodies are associated spatially with fields of secondary quartzites and mudstones that contain quartz veins with epithermal gold - silver mineralisation. The main vein mineral is quartz. Adularia, chlorite, illite, kaolinite and gypsum are present in minor amounts. The main ore minerals are pearceite and polybasite, whereas acanthite, freibergite series minerals, proustite, chalcopyrite, galena, pyrite, sphalerite and native gold are less common.
Argentopolybasite is a hydrothermal mineral, which formed from low- to moderate-temperature hydrothermal solutions (MM 87.382–395).

At the co-type locality Šibeničný vrch, Nová Baňa, Žarnovica District, Banská Bystrica Region, Slovakia, epithermal veins with silver - gold mineralisation are located in a Middle Miocene (15.97 to 11.63 million years ago) stratovolcano, represented mainly by andesitic rocks. Low- to intermediate- sulphidation epithermal veins and veinlets are hosted in an extrusive rhyolite body in the central part of the deposit. In the southeast and southwest parts of the deposit, the host rocks comprise ignimbrites and andesites.
The samples containing argentopolybasite were collected from the dumps of old workings. The ore shows typical low-sulphidation epithermal mineralisation with banded textures composed of adularia, chalcedony-like quartz and disseminated precious metal minerals.
Argentopolybasite is associated with acanthite, pyrargyrite, proustite, rozhdestvenskayaite-(Zn), naumannite and gold - silver alloys (MM 87.382–395).

At the Kremnica Au-Ag deposit, Kremnica, Žiar nad Hronom District, Banská Bystrica Region, Slovakia, the epithermal gold - silver deposit is located in the remnants of a large Miocene (23.03 to 5.333 million years ago) andesite stratovolcano. The deposit consists of a system of low-sulphidation epithermal veins with gold - silver - antimony mineralisation developed on marginal faults.
The samples with argentopolybasite were collected 10 cm wide hydrothermal quartz vein, that frequently contained drusy cavities with crystalline quartz, dolomite, siderite and abundant aggregates and crystals of silver sulphosalts such as argentopolybasite, polybasite, pyrargyrite, argentotetrahedrite-(Zn) and rozhdestvenskayaite-(Zn), as well as minor stephanite and miargyrite, and subordinate amounts of gold, naumannite and pyrite (MM 87.382–395).

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