Patent ID: 8304484

Claim:
A glass composition comprising, expressed in percent by mass: 50≦SiO 2 ≦60; 8≦Al 2 O 3 ≦15; 0≦MgO≦10; 5≦CaO<21; 5<SrO+BaO≦25; 10<MgO+SrO+BaO≦30; 0≦Li 2 O+Na 2 O+K 2 O<2; 2<TiO 2 ≦10; and wherein the content of SrO is greater than 5 percent by mass and the glass composition is substantially free from B 2 O 3 , F, ZnO, and ZrO 2 , and wherein the glass composition has a refractive index n d of 1.575 or greater and 1.595 or less.