The Amulet of Agamotto provides mystic illumination, penetrates illusions, and tracks both corporeal and ethereal beings by their psychic or magical emissions.
Strange Tales #110 (1963)
Description of powers (The Official Handbook Of The Marvel Universe Mystic Arcana: The Book Of Marvel Magic #1, 2007)
The Amulet of Agamotto, a similar but less powerful version of the Eye of Agamotto, appears to lack the Eye's ability to serve as a gateway to other dimensions. It is sometimes referred to as "the lesser Eye of Agamotto".