Abstract:
Sodalite and nosean were synthesized by hydrothermal and dry-sintering methods and also various coloured ultramarines by the latter method. Their characteristics were found to be similar to those of the corresponding natural minerals.
The hypotheses of the origin of the minerals of the sodalite group were made on the basis of the experimental investigations and reported field occurrences.
A blue ultramarine was pressed for the use of lapis lazuli substitute. It gemmological properties were studied and copared with those of natural and Gilson synthetic lapis lazuli.
