1. The microstructure of crystallized cristobalite, tridymite andmelanophlogite have been studied and the effect of crystallization on sintering of compositealso has been discussed.

2. This paper introduces the technology characteristics of cristobalite produced by direct calcination with nubby quartz.

3. The notes describe the common minerals such as quartz and its polymorphs, coesite, tridymite and cristobalite, feldspar, plagioclase, feldspathoids, pyroxenes, amphiboles, etc.

4. The basic influence of devitrification of silica-based ceramic core and the relation between cristobalite and core's properties have been investigated systematically in this article.

5. The results reveal that the increase of the sintering temperature and the hot-pressing pressure can promote the formation of cristobalite in the fibrous composites.

6. However, the biosilica obtained by the dry ashing method from rice shells directly is cristobalite silica.

7. It is found that it is very difficult to separate the cristobalite and quartz with similar size with montmorillonte from montmorillonte.