White Mirror is a Normal Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, White Mirror is Unlimited.
YGOPRODeck lists White Mirror for these formats: TCG, OCG, Master Duel.
A listed print of White Mirror appears in Brothers of Legend (BROL-EN051) at Ultra Rare rarity.
Among markets shown on this page, the lowest listed snapshot for White Mirror is about $0.21 on TCGPlayer (prices change frequently).
