Abstract
The logical ordering of complex mineral structures has been made to bring out hierarchical nature of their constitutions. The primary structure has neither substructure having other structure type nor pseudo-translations which relate it to other structure type. The types of the secondary structure of a given primary structure A (or B) may be classified into four categories: (1) super structures including simple substitution or distortion derivatives, A*, antiphase domain structures, iA, and structures characterized by commensurable density (or displacive) waves, Â, (2) modulated structure, Ã, (3) patchwork, M (A, B), or intergrowth, I(A, B), both consisting of A and B, and (4) domain structure, D(A), consisting of A with submicroscopic extension. Among these, the primary structures of A* and à are recognized by folding them with their pseudo-translations, and those in the remainings as substructures. The tertiary structure is characterized by the existence in it a substructure having a secondary structure. Likewise, more complex structures can be defined. Examples are: enstatite IV defines a tertiary structure i (A=high clinopyroxene), haüyne a quaternary structure D [I(Ã, B)] (A=nosean, B=haüyne end-member), and e-plagioclase a quinary structure I(iÃ*, B) (A=high anorthite, B=albite). Complex mineral structures are in general characterized by density (and displacive) waves which seem to generate, at their nodes, the boundaries of their substructures.
