Percussion Figure

percussion figure

[pər′kəsh·ən ‚fig·yər]
(crystallography)
Radiating lines on a crystal section produced by a sharp blow.

Percussion Figure

 

an arrangement of cracks on the face of a crystal, formed by the sharp impact of the blunted point of a steel center punch. The shape of a percussion figure reflects the symmetry of the crystal and the anisotropy of the crystal’s tensile strength.