Luminescent glass composition

Abstract

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.

Claims

1. A faceted gemstone of glass containing at least one dopant selected from the group of oxides of the rare earth metals scandium, lanthanum, cerium, praseodymium, samarium, europium, yttrium, terbium, dysprosium, holmium, thulium, ytterbium and lutetium, characterized in that the total amount of the oxides of rare earth metals is 2-2000 mg/kg of the glass composition, said glass comprising the following components: (a) 35 to 85% by weight SiO.sub.2; (b) 0 to 20% by weight K.sub.2O; (c) 0 to 20% by weight Na.sub.2O; (d) 0 to 5% by weight Li.sub.2O; (e) 0 to 13% by weight ZnO; (f) 0 to 11% by weight CaO; (g) 0 to 7% by weight MgO; (h) 0 to 10% by weight BaO; (i) 0 to 4% by weight A1.sub.2O.sub.3; (j) 0 to 2% by weight ZrO.sub.2; (k) 0 to 6% by weight B.sub.2O.sub.3; (l) 0 to 3% by weight F; (m) 0 to 2.5% by weight Cl; the stated amounts summing up to 100% by weight.

2. The faceted gemstone of glass according to claim 1, characterized in that the total amount of the oxides of rare earth metals is 5-700 mg/kg of the glass composition.

3. The faceted gemstone of glass according to claim 1, characterized in that a mixture of at least two oxides of the rare earth metals is employed.

4. The faceted gemstone of glass according to claim 1, characterized in that said faceted gemstone exhibits a fluorescence within a range of 300 to 3000 nm upon excitation by electromagnetic radiation.

5. The faceted gemstone of glass according to claim 1, wherein the faceted gemstone of glass is partially mirrored.

6. The faceted gemstone of glass according to claim 1, characterized in that a mixture of at least three oxides of the rare earth metals is employed.

7. The faceted gemstone of glass according to claim 1, characterized in that said faceted gemstone exhibits a fluorescence within a range of 300 to 1100 nm upon excitation by electromagnetic radiation.

8. A faceted gemstone of glass containing at least one dopant selected from the group of oxides of the rare earth metals scandium, lanthanum, cerium, praseodymium, samarium, europium, yttrium, terbium, dysprosium, holmium, thulium, ytterbium and lutetium, characterized in that the total amount of the oxides of rare earth metals is 2-2000 mg/kg of the glass composition, said glass comprising the following components: (a) 30 to 95% by weight B.sub.2O.sub.3; (b) 0 to 20% by weight K.sub.2O; (c) 0 to 25% by weight Na.sub.2O; (d) 0 to 5% by weight Li.sub.2O; (e) 0 to 13% by weight ZnO; (f) 0 to 11% by weight CaO; (g) 0 to 7% by weight MgO; (h) 0 to 10% by weight BaO; (i) 0 to 4% by weight A1.sub.2O.sub.3; (j) 0 to 5% by weight ZrO.sub.2; (k) 0 to 3% by weight F; (1) 0 to 2.5% by weight Cl; the stated amounts summing up to 100% by weight.

9. A faceted gemstone of glass containing at least one dopant selected from the group of oxides of the rare earth metals scandium, lanthanum, cerium, praseodymium, samarium, europium, yttrium, terbium, dysprosium, holmium, thulium, ytterbium and lutetium, characterized in that the total amount of the oxides of rare earth metals is 2-2000 mg/kg of the glass composition, said glass comprising the following components: (a) 30 to 95% by weight P.sub.2O.sub.5; (b) 0 to 30% by weight K.sub.2O; (c) 0 to 30% by weight Na.sub.2O; (d) 0 to 10% by weight Li.sub.2O; (e) 0 to 20% by weight ZnO; (f) 0 to 20% by weight CaO; (g) 0 to 15% by weight MgO; (h) 0 to 30% by weight BaO; (i) 0 to 15% by weight A1.sub.2O.sub.3; (j) 0 to 15% by weight SiO.sub.2; (k) 0 to 15% by weight B.sub.2O.sub.3; (l) 0 to 20% by weight BaO; the stated amounts summing up to 100% by weight.

10. A process for identifying a faceted gemstone made of glass according to claim 1, comprising the following steps: (a) providing a faceted gemstone made of glass according to claim 1; (b) exciting it with electromagnetic radiation; (c) detecting the generated fluorescence; and (d) optionally comparing the signal with a given pattern.

Description

LIST OF FIGURES

(1) FIG. 1: Measured fluorescence emission of a lead-free crystal glass according to Example 1 with 200 ppm Sm.sub.2O.sub.3 additive (excitation at 471 nm), measured on a cuboid of the size 40 mm12 mm12 mm.

(2) FIG. 2: Measured fluorescence emission of a high lead crystal glass according to Example 2 with 60 ppm Dy.sub.2O.sub.3 and 150 ppm Tb.sub.2O.sub.3 additives (excitation at 453 nm), measured on a cuboid of the size 40 mm12 mm12 mm.

(3) FIG. 3: Measured fluorescence emission of a soda lime glass according to Example 3 with 5 ppm Eu.sub.2O.sub.3 additive (excitation at 465 nm), measured on a cuboid of the size 40 mm12 mm12 mm.

(4) FIG. 4 (Comparative Example): Measured fluorescence emission of a soda lime glass without dopant addition (excitation at 465 nm), measured on a cuboid of the size 40 mm12 mm12 mm.

(5) FIG. 5: Schematic representation of the simulation set-up with the following legend: #1 light source with collimated beams of wavelength 450 nm; #2 chaton geometry; #3 fluorescence emission at 650 nm; #4 detector.

(6) FIG. 6: Simulation of fluorescence emission as a function of geometry and free path.

EXAMPLES

Examples 1 to 15

(7) The following Table 1 represents the oxide compositions of different glasses used for the preparation of the faceted gemstones. All amounts are stated as percentages by weight. The Examples relate to the following glasses:

(8) Example 1: lead-free crystal glass according to patent CZ302723 (cf. FIG. 1); Example 2: commercially available high lead crystal glass (cf. FIG. 2); Example 3: commercially available soda lime glass (cf. FIG. 3); Example 4: standard optical glass N-BK7; Example 5: commercially available borosilicate glass; Examples 6 to 15: commercially available colored glasses.

(9) All glasses contain the dopants in the amounts according to the invention.

(10) TABLE-US-00001 TABLE 1 Glass compositions with dopants (Part 1) Example 1 2 3 4 5 6 7 SiO.sub.2 59.11 55.25 72.69 70.30 80.24 72.28 70.30 PbO 31.90 K.sub.2O 3.49 8.80 7.70 0.20 4.00 5.90 Na.sub.2O 11.40 2.30 13.20 10.24 4.60 15.00 10.60 B.sub.2O.sub.3 3.07 0.30 10.00 12.60 Li.sub.2O 2.15 CaO 7.19 9.29 0.20 2.90 6.70 MgO 3.80 ZnO 7.71 1.00 1.10 Al.sub.2O.sub.3 0.43 0.70 2.30 0.10 1.60 TiO.sub.2 2.08 0.20 4.00 As.sub.2O.sub.3 Sb.sub.2O.sub.3 0.47 0.43 0.32 0.26 0.12 0.50 BaO 0.90 1.50 ZrO.sub.2 2.08 P.sub.2O.sub.5 0.70 Gd.sub.2O.sub.3 0.10 Nd.sub.2O.sub.3 1.30 SnO.sub.2 1.90 Sm.sub.2O.sub.3 0.0200 0.0300 Eu.sub.2O.sub.3 0.0005 0.0050 Ho.sub.2O.sub.3 0.1700 0.0500 Tb.sub.4O.sub.7 0.0150 0.0300 0.0300 Dy.sub.2O.sub.3 0.0060 0.0100 Sc.sub.2O.sub.3 0.0400 CeO 0.0400 Yb.sub.2O.sub.3 0.0300 Lu.sub.2O.sub.3 0.0300 Glass compositions with dopants (Part 2) Example 8 9 10 11 12 13 14 15 SiO.sub.2 73.00 69.10 65.29 64.94 65.73 70.57 71.93 73.80 PbO 0.90 K.sub.2O 7.50 11.00 4.70 2.20 2.60 0.70 Na.sub.2O 12.00 8.00 8.40 20.80 19.30 17.20 15.20 10.90 B.sub.2O.sub.3 2.00 3.80 4.10 2.40 1.00 CaO 2.80 7.00 6.40 4.80 4.20 3.30 5.30 7.00 MgO 2.70 0.20 0.10 0.20 0.10 0.20 ZnO 3.00 1.70 0.70 Al.sub.2O.sub.3 2.00 1.00 0.10 0.20 2.70 1.70 4.90 6.80 As.sub.2O.sub.3 0.70 Sb.sub.2O.sub.3 0.30 0.30 0.30 0.18 BaO 0.30 0.50 11.00 SrO 0.10 P.sub.2O.sub.5 3.80 F 1.30 0.50 Er.sub.2O.sub.3 1.80 Sm.sub.2O.sub.3 0.0100 0.0300 Eu.sub.2O.sub.3 0.0300 0.0200 0.0250 0.0200 Ho.sub.2O.sub.3 0.0200 0.0125 0.0100 Tb.sub.4O.sub.7 0.0300 Dy.sub.2O.sub.3 0.0300 0.0300 0.0200 0.0300 Sc.sub.2O.sub.3 0.0200 0.0500 0.0100 Y.sub.2O.sub.3 0.0200 0.0100 0.0100 La.sub.2O.sub.3 0.0400 0.0150 CeO 0.0125 Pr.sub.6O.sub.11 0.0300 0.0200 Tm.sub.2O.sub.3 0.0200 0.0300 0.0200 Yb.sub.2O.sub.3 0.0300 0.0300 0.0250 0.0300 Lu.sub.2O.sub.3 0.0300