Breaker Gorgon

The visor Rider wears over her Mystic Eyes is a Noble Phantasm, designed to allow management of the power emitted from her gaze. The visor functions by sealing the user's eyes within a self-contained world. The potency of this ability is so enormous that petrification occurs regardless of whether or not an individual looks into her eyes. This Noble Phantasm honors the Gorgon sisters, three sadistic monsters from Greek mythology.

Addtional source: Fate/Stay Night game translation v1.0a by Mirror Moon