Studies on (110) Fractured Faces of NaCl and Their Etch Patterns

Abstract
Fracture has been produced on NaCl crystals along (110) planes. The fractured surfaces are examined by multiple beam interferometry and it is found that they consist of elevated ridges and depressed valleys. Matched pairs of fractured faces have been etched and one to one correspondence in the number and position of the boat shaped pits have been established. While etching some fractured faces pyramidal hillocks have been observed. These hillocks have been studied in detail by successively etching the surface for two different periods and also by producing them on matched pairs. It is observed that they have no correlation on matched faces. The implications are discussed.