The 2e version:
Breath weapon/special abilities: This dragon's breath weapon is a cone of glowing shards; the cone is 60 feet long, 5 feet wide at the dragon's mouth, and 25 feet wide at the base. Creatures caught in the blast can save vs. breath weapon for half damage, and must make a second saving throw vs. breath weapon or be blinded by the dazzling shards for one turn per age level of the dragon. The shards shine as bright as daylight, and can be seen for miles. Creatures within 60 feet must save vs. breath weapon or be dazzled, incurring a penalty of -2 to attack rolls for one turn per age level of the dragon. A crystal dragon casts spells and uses magical abilities at 5th level, plus its combat modifier.
The 3e version:
Breath Weapon (Su): A crystal dragon's breath weapon is a cone of brilliant light. A target who fails his or her Reflex saving throw takes the indicated damage and is blinded for 1d4 rounds.