A high LTa, low UV and IR transmittance grey glass employing as its colorant portion iron (Fe2O3/FeO), erbium (Er2O3) and, optionally, titanium (TiO2). Enhanced effects are achieved by forming separate prebatch mixes, one of which includes rouge, metallic Si (optional), SiO and sand, the other including...http://www.google.es/patents/US6403509?utm_source=gb-gplus-sharePatente US6403509 - Grey glass composition and method of making same
