Quartz pseudomorph in an unusual crystal shape from Nishi-meya, Aomori Prefecture, Japan

Abstract

Quartz crystals in an unusual shape were collected from quartz veins running into the basaltic rocks in the Nishi-meya district, Aomori Prefecture. They take the shape of hexagonal bi-pyramid without hexagonal prism, whose apices are much more acute than those of high-quartz. They must be a pseudomorph after another mineral, but there are not a bit of residue. In this study, the original mineral phase is inferred from the detailed morphological examines. The DDR (deca-dodecasil 3R) type of clathrasil, which has not been discovered in nature, should be one of the most possible candidates.