'Hiroshima University - Department of Mathematics'
Abstract
The surface microtopographies of pyrophyllite crystals from various localities has been investigated by using transmission electron microscopy (TEM) with the Au-decoration technique. The pyrophyllite specimens investigated were collected from the southern Urals (Russia), California (USA), the north part of Vietnam, the southwestern part of Korean Peninsula and southwest Japan.
Gold-decoration successfully revealed growth steps (～1 nm in height) on the crystal surfaces. Pyrophyllite specimens from schistose and massive ores exhibit characteristically parallel growth patterns with narrow step separation, whereas polygonal spiral growth patterns with wider step separation are observed on crystal surfaces of pyrophyllite in veins. The morphology of pyrophyllite crystals seems to reflect the growth processes under different conditions (temperature and/or supersaturation), e.g., parallel steps on the irregular particles, on the other hand, polygonal spiral steps on polygonal plates
