Johnsomervilleite, a New Transition-Metal Phosphate Mineral from the Loch Quoich Area, Scotland

A. Livingstone
Department of Geology, Royal Scottish Museum, Chambers Street, Edinburgh EH1 1JF

Summary: Johnsomervilleite, Na10Ca6Mg18(Fe, Mn)25 (PO4)36 has Z = 3, a 15.00 Å, c 42.75 Å and cell volume 8330 Å3 and is a new rhombohedral species occurring in two metamorphic segregation pods in Moine gneiss of kyanite-sillimanite grade. Associated minerals are apatite, jahnsite, graftonite, mineral A, phosphosiderite, rockbridgeite, mitridatite, and vivianite. It is dark brown, brittle, and glassy, H = 4 1 2 , D = 3·35 (calc. 3.41) with a perfect basal (?) cleavage. Eight electron probe analyses are given and d spacings for 50 lines. The mineral, which is a Mg-Fe analogue of fillowite, is named after the late Mr J. M. Somerville who presented a specimen of garnet-quartz rock, which contained the new species, to the Royal Scottish Museum.

Mineralogical Magazine; September 1980 v. 43; no. 331; p. 833-836; DOI: 10.1180/minmag.1980.043.331.01
© 1980, The Mineralogical Society
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