A glass article is provided having from greater than or equal to about 40 mol % to less than or equal to about 68 mol % SiO2, less than or equal to about 11 mol % Al2O3, an R2O:R′O molar ratio of from greater than or equal to about 1:1 to less than or equal to about 2:1, and an MgO:CaO molar ratio of from greater than or equal to about 0.6:1 to less than or equal to about 1.8:1. The class article may also include a compressive stress layer on at least one surface thereof, the compressive stress layer having a compressive stress that is greater than or equal to about 800 MPa, and a depth that is greater than or equal to about 20 μm.