The cubic (̅43 m)/orthorhombic (mm2) phase transition temp. Tc of Mn-I, Zn-I, Ni-Br, and Cu-Br boracite was measured by polarized light microscopy in the pyramidal growth sectors. In either of the 5 compns. the (100), (110), (111), and (̅1̅1̅1) growth pyramids differ in a systematic way in Tc for each compn. A max. difference of ∼15 K between inequivalent sectors was obsd. in the same sample of both Zn-I and Cu-Br boracite. In a (100) growth sector of Ni-I boracite the cubic (̅43 mL')/monoclinic (m') transition is characterized by a sharp peak of dielec. const. ε', whereas in a strongly absorbing and birefringent (111) sector the anomaly is annihilated.