An unusual form of coated diamond

Abstract

another cassiterite-sulphide deposit, andorite in a much restricted occurrence has a composition of Ago.96Pbl.27Sb3.o3S 6 containing no tin (Huang, 1985). It appears that in these deposits the Sn present in the ore-forming environment formed tin minerals at relatively high temperatures, while andorite is a product of late-stage processes at lower temperatures. Recent analyses of andorite from various occurrences (Borodaev et al., 1971; Birch, 1981; Makovicky and Mumme, 1983 and Moelo, 1983) all show an absence of Sn.