An interpretation of the composition of high-silica sericites
- 1 December 1950
- journal article
- Published by Mineralogical Society in Mineralogical Magazine and Journal of the Mineralogical Society
- Vol. 29 (211) , 406-415
- https://doi.org/10.1180/minmag.1950.029.211.15
Abstract
The high-silica sericites generally contain a corresponding appreciable quantity of a divalent element, usually magnesium, and their chemical composition is interpreted as being intermediate between that of muscovite, KAl2 (AlSi3)O10(OH)2, and that of the equivalent high-silica mica leucophyllite, KAlMg (Si4)O10(OH)2. The series muscovite-leucophyllite includes the named micas phengite (high-silica sericite), mariposite, and alurgite. Selected analyses are plotted and fall on a corresponding straight compositional variation line from muscovite to leucophyllite. It is shown diagrammatically that the analysed sample of mariposite probably contained about 8 % of quartz. It is recommended that the only species names in this series to be retained are those of the end members muscovite and leucophyllite. Their indices of refraction and specific gravities are very similar.Keywords
This publication has 1 reference indexed in Scilit:
- On some minerals from the manganese mines of St. Marcel, in Piedmont, ItalyAmerican Journal of Science, 1893