New insulating Bi14(Sr0.33Ca0.67)5O26layered single crystals have been grown by a flux method and their crystallographic properties have been characterized. The crystals exhibited a smooth cleaved surface perpendicular to [001] orientation. The x‐ray precession camera analysis indicated the crystals have rhombohedral symmetry, belonging to a Laue group of 3¯m. Furthermore, some kinds of rare‐earth elements have been successfully substituted for lattice sites of the crystal. The variation of thec‐axis length reflected ionic radii of the rare‐earth elements substituted. Radiant luminescence has been observed in visible and infrared regions in the Er‐doped crystals, which was assigned to electron transition between spin‐orbit levels of trivalent Er ions in the crystal.