1977 Volume 8 Issue 5 Pages 272-285
A systematics has been given of pyroxenoid structures based on a symbolism that describes configuration of octahedral bands, the variation of which characterizes structure types. Types of octahedral bands of pyroxenoids can be classified into two categories, thereby defining two structural series of pyroxenoids; one has been denoted by w–p (wollastonite–pyroxene) series, and the other p–p (pectolite–pyroxene) series. Basic differences in crystal structure and chemistry between these series are compared. In terms of the characteristics of structural units, each consisting of one octahedral band and a pair of silicate chains, it has been further shown that the triclinic symmetry of pyroxenoids is in principle an inherent nature for pyroxenoids.