* magnificent emerald green color
* homogeneous hue throughout each single stone  stable in wax casting
* crystallographic structure equal to Spinel one  melting temperature 15001 - 750°C
* refractive index 1,5 - 1,7
* density 2.7 - 3,2 g/cm3
* Mohs scale of hardness 6,5 - 7°

Nanocrystal is a name for a group of new materials for jewelry or fashion jewelry, namely for nanosized (about 10-7 mm in dimensions) crystals grown in amorphous substance. We produce these materials by high-temperature synthesis at 1500-1750°C. The chemical composition of these materials is a mixture of oxides including silica, zirconia, alumina, zinc, lithium and magnesium oxides. Compositions and structures of proposed materials are widely diverse depending on their initial composition and synthesis method selected. As a result materials with various physical-chemical properties based on spinel, gahnite, sapphirine and other crystals are formed. Hardness of the suggested materials is 6.5-7 by Mohs scale, refractive index is 1.5-1.7, and density is 2.7-3.2 g/cm3. Nanosized crystals are homogeneously distributed in amorphous matrix. Their sizes and quantities are determined by crystallization schedule. Considering small crystal sizes special terms are to be kept for recording their X-ray diffraction patterns. Typical X-ray diffraction patterns are shown in Fig. 1. Nanocrystals are either colorless or colored. The distinguishing feature of these materials is that color centers are located in nanosized crystals. It is interesting that in the same initial material due to growth of nanocrystals of different characters, various color tints are available. For instance, in one sample depending on synthesis technique, the color can change consequently from yellow-green through blue-green to gray and purple. In the other sample color can change from blue to violet

The suggested raw materials for jewelry represent a new class of composites - nanocrystals. They have the properties of the most popular natural stones such as emerald, sapphire, ruby, garnet, topaz and aquamarine and etc.