# Difference between revisions of "Twin law"

### From Online Dictionary of Crystallography

Loi de macle </Font (Fr). Legge di geminazione (It)

# Twin law

The twin law expresses the operation that generate a twin. It is indicated by the symbol of the twinning element of symmetry: $\bar 1$, [uvw] and (hkl) for the centre of symmetry, direction of the rotation axis and Miller indices of the mirror plane, in the order. Usually, instead of the single (hkl) plane, the symbol {hkl} is used to indicate all the planes equivalent for symmetry.