在大别山超高压变质带中发现的柯石英多数已经完全退变为聚晶石英，并伴随着包裹它的外层基质的破裂现象，通过对这一现象的分析可以揭示变质岩形成的一些历史信息。在透射电子显微镜（TEM）下可以观察到石榴石柯石英包裹体分为石榴石基质层，退变石英层和柯石英层，以此建立一个三层复合球模型。基质石榴石层的pT轨迹可以看成与已知的外界变质岩轨迹一样，而内部石英和柯石英层在基质发生破裂前可看成降压降温的生长退变过程，这一体积增大过程最终导致石榴石层的破裂。模型根据已知的大别山变质岩的温度变化速率，计算出石榴石柯石英包体的发生破裂的温度条件，并模拟柯石英不同退变程度所对应的不同路径，从而得出变质岩不同的抬升路径。

用透射电子显微镜（TEM）观察产于大别山双河地区含柯石英硬玉石英岩矿物石英中纳米级至亚微米级的流体包裹体超微观结构特征发现：大多数包裹体呈圆形或负晶形（粒径大多为10nm～350nm），构成宽的密集的包裹体串。TEM揭示了柯石英和寄主矿物石英之间为共晶格取向连生关系，并寻找到在峰期变质条件下高盐流体存在的有力证据。流体包裹体经常伴随着许多相互连接的位错，并且与位错和位错壁等交生在一起，形成网络分布，这是在光学显微镜尺度下所不能探测到的。非爆裂的流体渗漏可能通过H2O或CO2分子沿位错的管道扩散，从包裹体进入寄主矿物石英，因而导致原来包裹体密度和成分的变化。

The microst ructural characteristics of syntactic polycrystal in the calcium rare earth fluorocarbonate minerals f rom Southwest China have been studied by means of selected area elec t ron diff raction and high resolution elect ron microscopy (HREM). The complication of the hetero geneous fabric of the minerals have been revealed by HREM. The result s show that the crystal st ructure of the minerals was formed by a disorder stacking of the unit layers of bast naesite and synchisite in the calcium rare earth fluorocarbonate minerals along c direction. The stacking fault and other crystal defect s in the syntactic polycrystal have been discussed.

The crystal structures and polytypism of bastnaesite-(Ce) (CeCO3F, B layer) and synchysite-(Ce) (CeCO3FWCaCO3, S layer) mineral series are very complicated in Sichuan Province, Southwest China. Four new polytypes: 6R, 2H2, 4H and 12H of the mixed-layer member CaCe3(CO3)4F3 (B2S) of this series were discovered by X-ray diffraction analyses and high resolution transmission electron microscopy, structural symmetry, cell and subcell parameters, possible space group, and structural stacking mode (dededgfg/T). They reveal that the mixed-layer member B2S is formed by the ordered stacking of two structural unit layers of bastnaesite-(Ce) (B layer) and one unit layer of synchysite-(Ce) (S layer) along the c direction. The forming of the new polytypes may depend on distributions and the periodical variation of orientation of the [CO3] groups between the unit layers of B2S. We have observed the {000l} microtwin of the 6R polytype and the syntactic intergrowths among the different polytypes formed by stacking faults in B2S.

Natural "monalbite" (MA) has been observed on a submicron-scale in jadeite along with high albite (HA) and low albite (LA) in jadeite quartzite in the Dabie ultrahigh-pressure (UHP) metamorphic terrane, China. Transmission electron microscope (TEM) observation of inclusions in jadeite crystals has revealed mineral phases with C2/m and C1-structures. The cell parameters of the C2/m crystal structure correspond to those of MA, whereas the cell parameters of C1-structure are identical to those of HA and LA. The existence of the C2/m structure shows that the jadeite underwent partial change to MA on a submicron-scale during retrograde metamorphism. Albite transformation twinning of HA suggests the transformation of MA into HA. MA occurrence provides powerful evidence of high-temperature metamorphism during exhumation, probably above 930℃. The preservation of MA may be due to the armouring by the jadeite and implies a very rapid cooling (quenching) during retrogression.