Glass composition for producing high strength fibers and high modulus

A composition for preparing glass fibers of high strength light comprising: SiO2 in an amount of about 69.5 to about 80.0% wt% of the total composition, Al2O3 in an amount of about 5.0 to about 18, 5 wt% by weight of the total composition, CaO in an amount of 0.0 to about 3.0 wt% by weight of the total composition, MgO in an amount of about 5.0 to about 14.75% by weight weight of the total composition, Li2O in an amount of about 3.25 to about 4.0 wt% by weight of the total composition, and Na2O in an amount of 0.0 to about 2.0 wt% by weight of the composition total.