Crystals

Crystals in Sword Art Online are considered to be one of the most convenient types of items. They have different uses, namely having immediate effect for recovery unlike potions and perform a variety of function outside of healing, extending to teleportation, corridors to locations, and displaying images or replaying voice messages.

Though extremely useful, they are expensive hence making people hesitant to use them. Their usage can also be prevented by a trap called an anti-crystal field, which later became normal for boss fights on the 74th floor and above.

Known Kinds

 * Antidote Crystals (Green) Cures Poision, and other things
 * Health Crystals (Red) Heals the person
 * Mirage Crystals
 * Teleport Crystals (Blue): transport the user to a chosen city's teleport gate
 * Corridor Crystals: open a teleport gate to any location that the player marked
 * Record Crystals: records what someone has said

Colors

 * Amaranth/Red - Full Health Recovery
 * Blue - Teleportation
 * Green - Status Recovery