| Abstract: | Results of microtopographical investigations on prism faces of cultured quartz crystals grown by hydrothermal crystallization techniques, undertaken with a view to determine the influence of microcrystals which get attached to the growing host prism face and then get detached, at some stage of growth, from or still remain attached to the host face, with special reference to the role played by them in the growth and development of host prism faces in particular and the quartz crystals in general, are discussed. The study is an extension of, and obviously to be dealt in continuation with, the earlier one (Part-I, see JOSHI , KOTRU ). Polygonal cavities of various shapes and structures observed on the prism faces are described. Mechanism of formation of the polygonal cavities is explained. Also described are pyramidal depressions, striations, growth hillocks, and etch pits within the cavities on the growing host prism faces. Some of the observed structures within the cavities are attributed to the imprints of the surface structures on the faces of detached microcrystals of quartz. Evidence of growth within the cavities is offered and the implications of such a growth are discussed. Evidence of micro-etching in the cavities is suggestive of the possibilities of some of the grown cultured quartz crystals to get etched in the autoclave. Two different suggestions are made for the interpretation of the origin of etch pits within the cavities, and there is support for the view that they are as a result of etching, only at a time when the supply quartz gets exhausted, of some of the grown crystals where the growing chamber is the hottest. |
