Geocronite n. : A lead-gray or grayish blue mineral with a metallic luster, consisting of sulphur, antimony, and lead, with a small proportion of arsenic.

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Taxonomy
Geocronite, mineral, free encyclopedia, endmember, antimony, arsenic, Sala, Sweden, search, formula, Pb14, Sb, solid solution, solution series, jordanite, grey, Sulfosalt minerals, crystals, sulfides.

Defination from the web:
Geocronite is a mineral, a mixed sulfosalt containing lead, antimony, and arsenic with a formula of Pb14(Sb, As)6S23. Geocronite is the antimony rich endmember of a solid solution series. The arsenic rich endmember is named jordanite. ...