Antimonselite from the new occurrence, Příbram uranium-base metal ore district (Central Bohemia, Czech Republic), has been studied by means of electron microprobe and X-ray diffraction. Antimonselite crystals, reaching up to 1.5 mm across, were rarely found in the calcite gangue with uraninite in association with clausthalite, tiemannite, hakite, tetrahedrite, Se-rich chalcopyrite, permingeatite, Se-rich and Se-analogue of chalcostibite and dzharkenite.
The structure was refined from single-crystal X-ray data to R1 = 0.0143 for 634 observed reflections. The structure of S-rich antimonselite is isotypic to that of stibnite.
Sulfur was found to be entering the selenium sites regularly without any evidence of preferential ordering of the atoms at the different sites.