2025 年 39 巻 1-4 号 p. 11-16
Three types of “Star of David” have been found from spinel crystals collected in Mogok, Myanmar:(1)Two triangular flat crystals contact with 60° rotation,(2)A hexagonal flat plate is inserted between the two triangular flat crystals and(3)A spinel twin is partially covered with a triangular flat crystal. Shapes of the “Star of David” crystals are readily understood when they are drawn in pseudo-trigonal system. The “Star of David” crystals are quite rare, and are found in Mogok. Therefore, I propose to call the crystals Mogok spinel-type twin.