The contrast of stacking faults in optical birefringence micrographs of diamond

The contrast of a stacking fault and one of its associated bounding partial dislocations observed by optical birefringence microscopy in diamond is described. Applying the theory of Tanner and Fathers for birefringence images of localized lattice defects in the presence of a background strain field, it is shown that the experimental observations in diamond indicate the presence of a thin lamella of material lacking cubic symmetry coincident with the fault. The optical anisotropy is consistent with a uniaxial lattice deformation normal to the fault.