Abstract

Single crystal x-ray measurements on galenobismutite from Nordmark Mines, Sweden (type specimen) give the following structural data: orthorhombic; space group, D2h16-Pnam or C2c9Pna2. Cell edges, a0 11.72 ± 0-03, b0 14.52 ± 0.03, c0 4.07 ± 0.02 Å. Unit cell contains Pb4Bi8Si6 = 4[PbS · Bi2S3]. Specific gravity 7.04 (highest of three measurements), 7.18 (calculated). Polished sections, white, strongly anisotropic; etch-reactions: HNO3, at once effervesces violently, etches deeply and leaves yellow deposit; HCl, gives a slight brown stain; KCN, FeCl3, KOH, HgCl2, negative.

Galenobismutite from Cariboo Gold Quartz Mine, British Columbia, and ‘lillianite’ from Mt. Farrell, Tasmania, gave powder patterns identical with that of the type material. ‘Lillianite’ from Gladhammar is shown by polished sections and x-ray photographs to be a mixture of galena and galenobismutite. Flink's crystals of ‘lillianite’ evidently represent the only known occurrences of distinct crystals of galenobismutite. These observations confirm the individuality of Sjögren's galenobismutite and show that ‘lillianite’ has no standing as a mineral species.

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