Patent ID: 8921246

Claim:
A glass composition comprising: an oxide containing oxides of Lu, Si, and Al, wherein the composition of the glass composition lies within a compositional region of a ternary composition diagram of Lu, Si, and Al in terms of cation percent, the compositional region being defined by the following six points: (32.3% LuO 3/2 , 30.0% SiO 2 , 37.7% AlO 3/2 ), (32.3% LuO 3/2 , 37.7% SiO 2 , 30.0% AlO 3/2 ), (20.8% LuO 3/2 , 55.0% SiO 2 , 24.2% AlO 3/2 ), (10.0% LuO 3/2 , 45.0% SiO 2 , 45.0% AlO 3/2 ), (20.8% LuO 3/2 , 24.2% SiO 2 , 55.0% AlO 3/2 ), and (30.0% LuO 3/2 , 25.0% SiO 2 , 45.0% AlO 3/2 ).