A geometric method incorporated with a computer program for indexing crystal faces of microcrystallites

A way of indexing microcrystallites is described in which analytical geometry is used. Two micrographs obtained at different tilting angles of the object are considered as the two orthogonal projections of the object on the XOY plane of a Cartesian coordinate system. The abscissae and the ordinates of three noncollinear points of each indexable habit face are determined by direct measurement and the Z coordinates are calculated. The habit faces are regarded as planes in three-dimensional space and the angle between each pair of indexable faces is calculated: The indexing is performed by comparing the calculated angles between the habit faces and the angles between the already known equilibrium planes (predicted by the theory). A computer program for experimental data processing is briefly described.