• journal_title：The Canadian Mineralogist
• Contributor：Dawei Meng ; Xiuling Wu ; Tao Mou ; Douxing Li
• Publisher：Mineralogical Association of Canada
• Date：2001-
• Format：text/html
• Language：en
• Identifier：10.2113/gscanmin.39.6.1713
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：39
• issue：6
• firstpage：1713
• section：Articles

Five new polytypes of parisite-(Ce) [CaCe₂(CO₃)₃F₂] from a rare-earth-mineral deposit within an aegirine-bearing granite pluton in Sichuan Province, southwestern China, were found by HRTEM: 6R₂, 8H, 14H, 36R and 42R. These new polytypes are all long-period ordered stacking structures, which may result from the distribution and the periodic variation in orientation of [CO₃] groups between the unit layers of parisite-(Ce). The observed microstructures may be affected by the rock-forming environment. These new polytypes coexist with the very common polytype 6R₁, disordered stacking series, and mixed-layer structures developed in the host polytype, 6R₁.