Abstract
LONDON. Mineralogical Society, June 9.—G. E. L. Carter: On an occurrence of vanadiferous nodules on the coast of South Devon. The author describes an occurrence of vanadiferous nodules in the red marls that underlie the Budleigh Salterton pebble beds on the coast of South Devon. These nodules consist of siliceous and argillaceous material impregnated with vanadium oxide and calcium earbonate. A typical nodule examined at the Imperial Institute showed a roughly concentric structure, ill-defined black shells alternating with shells of light-coloured material. Radiating black bands stood out as ribs on the surface of the nodule. Analyses by Miss Hilda Bennett showed that the black portion of the nodule contained 13.96 per cent of vanadium oxide, estimated as pentoxide. The light-coloured portion of the nodule contained only 1.91 per cent of vanadium oxide, and was relatively richer in calcareous and siliceous matter than the blacker and more vanadiferous portion.—M. H. Hey: Studies on the zeolites. Part 2: Thom-sonite (including faroelite) and gonnardite. A chemical, optical, and X-ray study of a considerable number of thomsonite specimens has led to the conclusion that thomsonite and faroelite form a continuous isomorphous series. The true symmetry of thomsonite is shown to be didigonal polar (C20). The unit cell is shown to contain (Ca,Na)6(Al,Si)20O40.12H2O. The mean refractive index ranges from 1.517 to 1.535, falling with increase in the Si/Al ratio. Apparatus has been designed and applied to measure the vapour pressure of thomsonite at various temperatures and degrees of dehydration, and it appears very probable that a dimorphous high-temperature form exists, the transition being readily reversible. Gonnardite is probably identical with the high-temperature dimorphous form of thomsonite (meta-thomsonite), and is therefore to be regarded as a separate species.—A. Russell: An account of British mineral collectors and dealers in the seventeenth, eighteenth, and nineteenth centuries. A second instalment: John Woodward (1665–1728) and Charles Francis Greville (1749–1809). L. J. Spencer: Hoba (South-West Africa), the largest known meteorite. The large mass of meteoric iron discovered in 1920 on Hoba West farm, 12 miles west of Grootfontein, measures about 10 9 feet on its flat upper surface, and is estimated to weigh 60 metric tons. It belongs to the group of nickel-rich ataxities. Chemical analysis by Mr. M. H. Hey shows iron 83.44 per cent, nickel 16.24 per cent, with small amounts of cobalt, copper, sulphur, phosphorus, and carbon. Photomicrographs ( 820) by Dr. J. M. Robertson show a minute plessite-like structure.—L. J. Spencer: Twelfth list of new mineral names. Since the publication in 1928 of the eleventh list of this series (the first was in 1897), 120 names have been collected from the current literature. In addition to the bibliographical reference, a brief description of the essential characters of the mineral and derivation of the name are given.—J. Drugman: On different habits of fluorite crystals. In fluorite the cube is usually the predominating form. Crystals of other habits octahedral, rhombic-dodecahedral, and triakis-octahedral are described. The temperature during the growth of the crystal has perhaps influenced its habit.
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Societies and Academies. Nature 128, 42–43 (1931). https://doi.org/10.1038/128042a0
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DOI: https://doi.org/10.1038/128042a0