CPC C03C 10/0054 (2013.01) [A44C 17/008 (2013.01)] | 13 Claims |
1. A glass ceramic material for the production of fashion jewellery and jewellery stones with a high refractive index of at least 1.62 and a high heat resistance having a melting point of at least 1550° C., characterised in that it is formed by aluminium-boron-silicate glass with the addition of ZnO and MgO oxides, which forms by subsequent heat treatment a homogeneously dispersed nanocrystalline phase consisting of (in weight %):
20-40% SiO2,
1.5-10% B2O3,
20-35% Al2O3,
0.1-20% MgO,
0.1-20% ZnO,
while the content of MgO+ZnO is at least 10%, and
as nucleation agents for controlled bulk crystallization:
0.1-15% ZrO2,
0-15% TiO2,
while the content of TiO2+ZrO2 is at least 5%.
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