Rotation twin
From Online Dictionary of Crystallography
Macle par rotation (Fr). Achsenzwilling, Rotationszwilling (Ge). Geminato per rotazione (It). 回転双晶 (Ja). Macla de rotación (Sp).
Definition
Two domains of one crystal form a rotation twin when the twin operation is a rotation about a lattice row (twin axis).
1. Irrational twofold twin axis normal to a rational lattice plane. This lattice plane is common to both twin partners.
2. Rational twofold twin axis normal to an irrational plane. This lattice row is common to both twin partners.
See also
- Chapter 3.3 of International Tables for Crystallography, Volume D