Stripped of her outer garments, which he behind her against the back of her throne, the last and most regal of the sibyls turns in a superb contrapposto movement to close her book and replace it on its desk while she looks downward at the altar, ready to step from her throne. Scroll under arm, one of her attendant putti points back toward her as both children depart. She has no need of book or scroll; her whole being is absorbed in the ultimate reality on the altar whose light irradiates her Hellenic features.

The vast symphonic structure of Michelangelo's color is especially well seen in this illustration, ranging from the deep, rich tonalities of the spandrels and lunettes, intensifying the natural shadow of their positions, through the bright garments to the gray-white of the simulated marble. The figure is dominated by an orange-lavender dialectic of throbbing intensity. The bodice is orange, with white highlights and reddish shadows; the rose lining is turned up to reveal a lavender shift, always the color of divinity on the Ceiling, punctuated by hanging gray scarves. The border and the belt of the bodice are gray with gold-yellow buttons. The outer dress before which Libyca sits is a splendid green, with yellow-gold.