crystal twinning
two separate crystals sharing some of the same crystal lattice points in a symmetrical manner
en-US/ˈkɹɪstəl ˈtwɪnɪŋ/
en-GB/ˈkɹɪstl ˈtwɪnɪŋ/
two separate crystals sharing some of the same crystal lattice points in a symmetrical manner