The embodiments described herein relate to chemically and mechanically durable glass compositions and pharmaceutical packaging formed from the same. According to one embodiment, a glass for pharmaceutical packaging includes from about 70 mol. % to about 80 mol. % SiO2; from about 4 mol. % to about 8 mol. % alkaline earth oxide, the alkaline earth oxide comprising MgO and CaO; X mol. % Al2O3, wherein X is from about 4 to about 8; and Y mol. % alkali oxide comprising non-zero amounts of Na2O and K2O, wherein Y is about 9-15 mol. % and a ratio of Y:X is greater than 1.