Bull. Minéral. (1981), 104, 508-525.
Mineralogical study of complex Pt-Fe nuggets from Ethiopia
by Louis J. CABRI (x), Alan J. CRIDDLE (2), J. H. Gilles LAFLAMME 0), Graham S. BEARNE (2) and Donald C. HARRIS (1),
(*) Mineral Sciences Laboratories, Canada Centre for Mineral and Energy Technology, 555 Booth Street, Ottawa, Canada, K1A OG1.
(2) Department of Mineralogy, British Museum (Natural History),
Cromwell Road, London SW7 5BD, U.K.
Etude minéralogique de pépites Pt-Fe complexes provenant d'Ethiopie.
Introduction
In 1928 the British Museum was presented by Hugh S. Gordon Esq., of London, with two groups of concentrates from the alluvial platinum workings on the Joubdo (Joubda, Youbdo, Yubda) stream, Birbir River, Ethiopia (Abyssinia). In the same year Duparc ajîd Molly reported on the geology, and distribution of platinum, in the Birbir River area. Our study of the mineralogy of the concentrates has revealed that they consist predominantly of Pt-Fe alloy, and contain an extensive suite of primary inclusions. These inclu¬ sions, and their matrix, were examined with the ore
microscope ; their compositions determined with the electron probe ; their reflectance spectra, from 400-700 nm, in air and in oil, measured; and colour values computed. In addition, the morphology of some Pt-Fe nuggets was examined With a scanning electron microscope (SEM).
Morphology and surface characteristics of the nuggets
The concentrates, when presented to the Museum, consisted of two phials, one containing 5 grams of
