Glass batch compositions for the formation of high-modulus, and high-strength glass fibers as well as fibers suitable for use as textile and reinforcements are disclosed. Fibers formed of the composition are especially suitable for use in high-strength, low-weight applications such as windmill blades and high strength and modulus applications where strength and stiffness are required in the composite. The glass composition is up to about 70.5 weight % SiO2, about 24.5 weight % Al2O3, about 22 weight % alkaline earth oxides and may include small amounts of alkali metal oxides and ZrO2. Additionally, glass fibers formed from the inventive composition are non-corrosive or substantially non-corrosive in nature. Due to the non-corrosive nature of the glass fibers, glass fibers made with the inventive composition may be used in applications where the glass fibers or a composite formed from the glass fibers are in contact with a corrosive substance.