Patent ID: 8852764

Claim:
A crystallized glass substrate for information recording medium, consisting of a crystallized glass which comprises the components of SiO 2 of from 40% to 60%, Al 2 O 3 of from 7% to 19%, and ZnO of from 5% to 25%, RO of from 5% to 35% in terms of % by mass on the oxide basis, wherein R is one or more selected from Zn, Mg and Fe, and B 2 O 3 of from 3.0% to less than 8%, and which comprises one or more selected from RAl 2 O 4 and R 2 TiO 4 as a main crystal phase, wherein R is one or more selected from Zn, Mg and Fe, and wherein the main crystal phase has a crystal grain size in a range of from 0.5 nm to 20 nm, a degree of crystallinity of 15% or less, and a specific gravity of 3.00 or less.