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

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%,
• after crystallization ≥20% of a crystalline phase of a spinel type and a crystalline phase related to a nucleation agent selected from the group consisting of ZrO2 and ZrTiO4.

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%, and 0.08-20% of colouring additives selected from the group consisting of:
• CoO, NiO, CuO, Fe2O3, MnO2, Cr2O3, V2O5, Pr2O3, CeO2, Nd2O3, Er2O3, AgO and Au.

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
• 0.1-20% of colouring additives selected from the group consisting of:
• CoO, NiO, CuO, Fe2O3, MnO2, Cr2O3, V2O5, Pr2O3, CeO2, Nd2O3, Er2O3, AgO and Au,
• characterised in that it comprises after crystallization ≥20% of a crystalline phase of a spinel type and a crystalline phase related to a nucleation agent selected from the group consisting of ZrO2 and ZrTiO4, and
• characterised in that a size of crystalline particles is ≤50 nm and the material is transparent.

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 luminium-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
• 0.1-20% of colouring additives selected from the group consisting of:
• CoO, NiO, CuO, Fe2O3, MnO2, Cr2O3, V2O5, Pr2O3, CeO2, Nd2O3, Er2O3, AgO and Au,
• characterised in that it comprises after crystallization ≥20% of a crystalline phase of a spinel type and a crystalline phase related to a nucleation agent selected from the group consisting of ZrO2 and ZrTiO4, and
• characterised in that a size of crystalline particles is >50 nm and the material is translucent or opaque.