Patent ID: 7135425

Claim:
A grey glass comprising: a base glass portion comprising: Ingredient wt. % SiO 2 67–75% Na 2 O 10–20% CaO 5–15% MgO 0–7% Al 2 O 3 0–7% K 2 O 0–7% and a colorant portion consisting essentially of: total iron (expressed as Fe 2 O 3 ) 0.05 to 0.35% erbium oxide 0.05 to 0.25% selenium (Se) <=15 ppm cobalt oxide 5 to 60 ppm wherein the grey glass has a redox value (FeO/Fe 2 O 3 ) of at least 0.35, a visible transmittance (Lta) of at least 65%, a dominant wavelength in the range of from 435 nm to 570 nm, and an excitation purity (Pe) of no greater than 4.5%.