Original paper
The conoscopic figures of some macroscopically overgrown dioctahedra micas
[Die Konoskopbilder einiger makroskopisch verwachsener, dioktaedrischer Glimmer]
Banno, Shohei; Yamasaki, Masao
Neues Jahrbuch für Mineralogie - Monatshefte Jg. 1972 Heft 11 (1973), p. 514 - 523
3 references
published: Jan 24, 1973
DOI: 10.1127/njmm/1972/1972/514a
ArtNo. ESP156197211004, Price: 19.00 €
Abstract
The conoscopic figures of two macroscopically overgrown dioctahedral micas consisting of 3T and 2M1 and of two 2M1 components were calculated by computer. The conoscopic figures of the 3T and 2M1 overgrowth viewed normal to (001) generally exhibit two isolated isogyres restricted to the neighbourhood of melatops and exhibit cross-shaped isogyre when 2M1 is in the orthogonal position. Overgrowth of 2M1 and 2M1 rotated 120° around the normal to (001) also exhibits two isolated isogyres localized near the melatopes, and a continuous isogyre resembling that of a single 2M1 crystal at certain positions. The comparison of calculated and observed conoscopic figures of muscovites from low-grade schists is briefly discussed.
Keywords
Microscopy (conoscopic) • computer • mica • intergrowth