Abstract
Osarizawaite, a new mineral. from the Osarizawa mine occurs in the oxidized zone of lead-zinc-copper veins as earthy and friable masses, associated with other secondary minerals of lead or copper. The chemical formula of osarizawaite has been determined as Pb (Cu0.98 Zn0.02) (Al0.81 Fe0.1 ?? )2 (SO4)2 (OH)6. Its physical and optical properties are: greenish-yellow in colour; specific gravity=3.89-4.02, 4.20 (calc.); mean index of refraction=1.735-1.757, birefringence strong. The unit cell dimensions for both the hexagonal cell and the corresponding rhombohedral cell are: α0=7.05Å., c0=17.23Å., Z=3; αrh=7.04Å., α=60°06′, Z=1. The data obtained demonstrate that the mineral is a new species being the aluminum analogue of beaverite and belongs to the alunite group. A new mineral name, osarizawaite, is proposed for the mineral which belongs to the alunite group and whose ideal chemical formula is PbCuAl2(SO4)2(OH)6 where Cu and Al may be partially replaced by Zn and Fe respectively.
