Asteroid 21 Lutetia at 3 μm: Observations with IRTF SpeX

► We observed Lutetia three times from 2003-2008 and reconsidered 1996 observations. ► Lutetia's southern hemisphere shows 3-μm band depths of ∼3-5%, with band depths of 0-2% in the northern hemisphere. ► Shorter-wavelength observations by other workers shows hemispheric-level variation consistent with 3-μm results.