Patent ID: 7666806

Claim:
A glass composition comprising a base glass composition comprising: SiO 2 65 to 75 weight percent, Na 2 O 10 to 20 weight percent, CaO 5 to 15 weight percent, MgO 0 to 5 weight percent, Al 2 O 3 0 to 5 weight percent, K 2 O 0 to 5 weight percent, and BaO 0 to 1 weight percent, and a colorant and property modifying portion comprising: total iron 0.25 to 0.9 weight percent, Cr 2 O 3 6 PPM to 400 PPM, Er 2 O 3 0.3 to 3.0 weight percent, TiO 2 0.1 to 0.8 weight percent, wherein the glass composition has a redox ratio in the range from 0.15 to 0.62 and the weight percent of the ingredients of the colorant and property modifying portion are selected to provide a glass piece that exhibits an Lta of equal to or greater than 60 percent at a thickness of 0.1535 inches (3.9 mm).