Glass ceramic material of a spinel type for the production of fashion jewellery and jewellery stones

Abstract

Glass ceramic material for the production of synthetic stones in fashion jewellery and jewellery, having excellent mechanical properties, chemical and heat resistance, harmless due to absence of lead, arsenic and cadmium compounds, available in a broad scale of colour designs, imitating faithfully natural precious stones thanks to high content of spinel crystalline phase and lowered content of SiO2, consisting of (in weight %): 20-40% SiO2, 1.5-10% B2O3, 20-35% Al2O3, 0.1-20% MgO, 0.1-20% ZnO, the content of MgO+ZnO being at least 10%, preferably also 0-15% TiO2, 0.1-15% ZrO2, the content of TiO2+ZrO2 being at least 5%, more preferably also 0-20% of colouring additives in the form of CoO, NiO, CuO, Fe2O3, MnO2, Cr2O3, V2O5, Pr2O3, CeO2, Nd2O3, Er2O3, AgO and Au.

Dependencies are inferred from the claim text.