Patent ID: 8283268

Claim:
A metal colloid-colored glass ceramic made by ceramicizing a colorless transparent precursor glass, said colorless transparent precursor glass comprising, a combination of at least one metal colloid former and at least one redox partner capable of reducing said at least one metal colloid former to a metallic state; wherein said at least one metal colloid former contains at least one metal selected from the group consisting of Au, Ag, As, Bi, Nb, Cu, Fe, Pd, Pt, Sb and Sn and said at least one redox partner contains at least one element selected from the group consisting of As, Ce, Fe, Mn, Sb, Sn and W; with the proviso that the at least one metal colloid former and the at least one redox partner are different from each other; wherein said precursor glass consists of a magnesium-alumino-silicate glass with a composition, in percent by weight on an oxide basis, of: SiO 2 45.0-62.0 Al 2 O 3 15.0-25.0 MgO 2.0-10.0 ZnO 2.0-15.0 BaO 0-3.0 SrO 0-3.0 TiO 2 0.5-8.0 ZrO 2 0.5-4.0 P 2 O 5 0 B 2 O 3 0-5.0; whereby the metal colloid-colored glass ceramic contains at least a part of said at least one metal in said metallic state.