Domain Structure in Calcium-Cerium Fluorocarbonate Minerals, Mianning County, Sichuan Province, China

The domain structures in calcium cerium fluorocarbonate mineral series from a rare earth mineral deposit within an aegirine alkali granite massif in Mianning County, Sichuan Province, China, were studied by means of transmission electron microscopy. Many categories of domain structures in this mineral series were observed and investigated, including the microtwin domains of parisite 6R 2 and B 2S 6R, the antiphase domains of B 2S 2H. The results show that the antiphase domains which are faults along crystal plane (0001) are formed by the displacement of crystal lattice in c * direction and the displacement is 0 471 nm. A new polytype (B 4S 2 3R) of regular mixed layer structure with B 4S 2 type is found in the domain region of mixed layer structure.