crystal twinning*Mineral galleries – twins*Mathematical and Theoretical Crystallography*Quartz Crystals – Twinning*Grain Boundary Twinning
==Sklici====Vir==* Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20. izdaja, ISBN 0-471-80580-7==Zunanje povezave==*Tulane Edu.