Stratigraphical Etch Patterns on the Rhombohedral Cleavages of Natural Quartz Crystals

M. S. Joshi and Baby K. Paul
Department of Physics, Sardar Patel University, Vallabh Vidyanagar, Gujarat State, India

Summary: Rhombohedral cleavage faces of quartz have been etched hydrothermally and with fused KOH. Stratigraphical etch patterns were observed on isolated cleavages, matched cleavage faces, and opposite sides of a thin flake. The angle between the (101¯1) cleavage plane and the planes responsible for the stratigraphical patterns was almost equal to the interfacial angle, 46° 16′ between adjacent rhombohedral faces. It is concluded that the stratigraphical patterns formed by preferential etching reveal the edges of weak planes deposited during growth. The implications are discussed.

Mineralogical Magazine; December 1973 v. 39; no. 304; p. 482-487; DOI: 10.1180/minmag.1973.039.304.13
© 1973, The Mineralogical Society
Mineralogical Society (