The stellate morphology of our crystals resembles that of cyclic twinned crystals observed in minerals (chrysoberyl,(37) benitoite, aragonite and diamond ) and biominerals (aragonite plates in gastropod nacre(39)) (Figure ). In these cyclic twins (a form of polysynthetic twinning), the radiating profile and protruding lines define morphological sectors that are also distinct crystallographic domains . The concave angles of these examples are inconsistent with single crystallinity and are indicative of twinned crystals. We have proven that in our crystals, both the multidomain appearance and the concave angles co-exist with single crystallinity. Our observations are not obvious considering the conventional crystallographic rules. The symmetry of the crystal morphology correlates with the expected point group, 622. However, the crystal morphology is not among the expected forms (i.e., hexagonal trapezohedron, dihexagonal prism, hexagonal dipyramid or hexagonal prism) for the relative point group 622, nor for any of the other point groups.