ABSTRACT
The plane or system of planes of a crystalline phase along which some phenomenon, such as twinning or transformation, occurs. See crystal structure.
(1) A line on a glass crack surface, running parallel to the local direction of cracking, separating parallel but noncoplanar portions of the crack surface. (2) A nely structured fracture surface marking that gives a matte or roughened appearance to the surface, having varying degrees of coarseness. Finely structured hackle is variously known as ne hackle, frosted area, gray area, matte, mist, and stippled area. Coarsely structured hackle is also known as striation. See also mist hackle, shear hackle, twist tackle, and wake hackle.
