XU Jin-sha1, SHEN Gan-fu1, LI Guo-wu2
(1. Chengdu Institute of Geology and Mineral Resources, Chengdu 610082, China;
2. China University of Geosciences, Beijing 100083, China)
Abstract: Dingdaohengite-(Ce) is a new rare-earth element mineral species from the Bayun Obo REE-Nb-Fe Mine, Inner Mongolia, China. The mineral should be regarded as both a Ti-analogue at the C(1) site of chevkinite-(Ce) subgroup and a ture polymorph of perrierite-(Ce). At the same time, it is the first example for the chevkinite-(Ce) subgroup with P21/a space group in nature, too. Later, dingdaohengite-(Ce) with C2/m space group from the Panzhihua V-Ti-Fe Mines was discovered. Except space group, there is a close parallel in physical and chemical features between the two modifications. To be precise, it is suggested that dingdaohengite-(Ce) with P21/a space group is favourably refered as P21/a dingdaohengite-(Ce), Similarly, dingdaohengite-(Ce) with C2/m space group as C2/m dingdaohengite-(Ce). The discovery and study of C2/m dingdaohengite-(Ce) reveal that the available genetic explanations, for the question that why there are two different interior symmetry to the chevkinite subgroup, can not illuminate the origin of the two space groups.
Key words: dingdaohengite-(Ce)；P21/a space group; C2/m space group; mineralogical characteristics ; genetic contrary to reason.
E-mail: xujinsha117@yahoo.com.cn
ACTA MINERALOGICA SINICA Vol. 32, No. 4, 2012, Page 486-492
