Arcane Sight(Tome and Blood: A Guidebook to Wizards and Sorcerers)
Level: Sorcerer 3, Wizard 3, Hexblade 3 (Arcane), Spellthief 3,
Components: V, S,
Casting Time: 1 action
Duration: 1 minute/level
This spell makes your eyes glow blue and allows you to see magical auras within 120 feet of you.
The effect is similar to a detect magic spell, but works much more quickly.
You know the number of auras within your sight, and the strength and location of each aura.
An aura's magic school and strength depend on a spell's functioning level or an item's caster level, as noted in the description of the detect magic spell (see page 193 of the Player's Handbook).
If you spend a full-round action scrutinizing a creature within 120 feet of you, you can determine if it has any spellcasting or spell-like abilities, whether they are arcane or divine (spell-like abilities register as arcane), and the strength of the most powerful ability the creature currently has available for use.
In some cases, the spell may give a deceptively low reading, such as when you use it on a spellcaster who has used up most of her daily spell limit.