UNUSUAL INCLUSIONS IN NATIVE GOLD FROM THE MIR KIMBERLITE PIPE

Abstract

We found about 50 gold grains in the heavy fraction obtained by dissolving large-volume samples of serpentinized and carbonatized kimberlite from the Mir pipe. Many of them were full of inclusions of other phases. These inclusions are of indisputable genetic interest, as is the native gold itself. It forms angular, lumpy and flaky grains 0.2 to 1.8 mm long, 0.1 to 0.6 mm wide and 0.05 to 0.8 mm thick. Their surfaces are uneven and rough, being covered with sproutlike growths and projections. Of the 33 gold grains studied, 26 proved to be very high-assay. The presence of an unusual association of gold minerals in the Mir-pipe suggests that alkalic mafic magma similar in composition and origin to kimberlite magma is potentially gold-bearing.