Abstract
Growth textures and twin boundary structures of quartz twinned after Japan Law were studied by observations of etch figures and cathode luminescence, and molecular dynamics (MD) simulations. Near the composition plane of Japanese twin, hourglass-shaped sectors are observed to have mosaic textures composed of polysynthetic Brazil twin. This sector corresponds to a growth sector of {10-11} or {01-11}, where the composition plane is smooth and flat {11-22}.
From the MD simulations, it is shown that {11-22} is the only composition plane that does not incorporate dislocations, and that dislocations are not required at a junction of Japanese and Brazil twin boundaries.
These facts indicate that {11-22} composition plane of Japanese twin serve as a source of Brazil twin during the course of growth.
