The exterior of the entry rotunda to the 180,000-square-foot museum is inscribed with 30-inch-tall letters that read: "The Story of Texas" and "Texas State History Museum." The building is almost entirely clad in the locally quarried Sunset Red granite - the same material employed for The Texas State Capitol Building. Random-sized pieces of the stone - some as large as 9 feet long and 6 feet wide - were installed for the exterior. The Sunset Red granite was also used as paving for the courtyard plaza and for parts of the dining deck on the second floor.
To contrast the Sunset Red granite, Carnelian granite was employed for the base of the building as well as for the accent band on both its interior and exterior. This darker colored granite was chosen to complement the lighter "salmon" color of the Sunset Red granite, according to the architect. The small rock-faced Carnelian granite pieces ranged in size from 2 to 4 feet in length.