Makovickyite and cupromakovickyite from the Obari mine, Yamagata Prefecture, Japan

Abstract

Makovickyite (Ag_1.5Bi_5.5S₉) and cupromakovickyite (Cu₈Pb₄Ag₂Bi₁₈S₃₆) have been found in the Ohari mine, Tsuruoka City, Yamagata Prefecture, Japan. Makovickyite and cupromakovickyite occur in the chalcopyrite-muscovite-quartz ore. The empirical formula of makovickyite is Ag_1.27Cu_2.60Bi_10.25Pb_0.28S₁₈ (based on ΣS = S+Te+Se = 18). The unit cell parameters from the X-ray single cristal of the mineral are a = 13.246 (2), b = 4.055 (7), c = 14.679 (2) Å, β= 99.469 (2)°, V = 777.77 (3) Å ³ The empirical formula of cupromakovickyite is Ag_2.43Cu_8.66Bi_18.07Pb_2.32S₃₆ (based on ΣS = S+Te+Se = 36).