Patent ID: 8609561

Claim:
A colorless transparent colloid-former-containing glass that is convertible into a transparent colorless glass ceramic or a metal colloid-colored glass ceramic, said colorless transparent colloid-former-containing 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, Cu, Pd and Pt, 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; and wherein said redox partner comprises As 2 O 3 and said As 2 O 3 is present in the glass in an amount of from 0.93 to 3.0 wt. %; or said redox partner comprises Sb 2 O 3 and said Sb 2 O 3 is present in the glass in an amount of from 1.59 to 6.0 wt. % or said redox partner comprises SnO 2 and said SnO 2 is present in the glass in an amount of from 0.97 to <1.9 wt. %.