D. Swarovski & Co.

D. Swarovski Kg

Gerold Sprachmann

Johannes Maier

Wolfgang Porcham

Florian Meissl

Rainer Haid

Norbert Bilek

Roy Debbage

Helmut Judmaier

Michael Schlamadinger

The invention relates to faceted gemstones based on a luminescent glass composition that contains particular oxides of rare earth metals and thus enables the faceted gemstones to be identified, and to a process for identifying the gemstones.

Luminescent glass composition

A lead- and barium-free crystal glass having a refractive index of at least 1.55, with in % by weight, more than 50% and less than 60% SiO, more than 0.6% and less than 4% BO, less than 3% KO, more than 12% and less than 15% NaO, more than 4% and less than 11% CaO, more than 0.25% and less than 5% AlO, less than 2% MgO, and between 8 and 16% ZnO, with the proviso that the total content of the oxides of Pb, Ba and As is below 0.1%, the total content of the oxides of Ti and La is below 5% and the total content of the oxides of Nb, Ta, Yb, Y, W, Bi and Zr is below 5%, wherein at most 1% oxides of Nb, Ta and Yb respectively and 3% of the oxides of Y, W, Bi and Zr respectively are included.

Lead- and barium-free crystal glass

A glass composition substantially comprising silicon oxide, calcium oxide and aluminum oxide, and its use for producing gems.

Gem comprised of a glass based on silicon oxide and calcium oxide

Growing community of inventors

Kolsassberg, Austria

Gerold Sprachmann