microgranulitic

Century Dictionary and Cyclopedia

1. In lithology, an epithet applied by Lévy to a form of granitoid structure which is so finely crystallized that it cannot be recognized by the naked eye, but which, under the microscope, is revealed as being made up of crystalline individuals each having its own independent orientation, so that in polarized light it presents the appearance of a brilliantly colored mosaic. The microgranulitic structure, as “this term is used by Lévy, differs from the micropegmatitic in the crystalline individuals of the latter having all one common orientation.