The Mineralogy of the Potassium-Barium Feldspar Series I. The Determination of the Optical Properties of Natural Members

N. N. Roy
Department of Mineralogy and Petrology, Cambridge

Summary: Variation diagrams for the optic properties and densities of natural specimens within the series have been determined. They focus attention on two composition regions at about 45 % Cn and 65 % Cn. The significance of the first of these is uncertain, but it is suggested that the discontinuity at 65 % Cn is related to structural changes that take place at this composition.

Mineralogical Magazine; September 1965 v. 35; no. 271; p. 508-518; DOI: 10.1180/minmag.1965.035.271.06
© 1965, The Mineralogical Society
Mineralogical Society (