Clementine imaged the Moon entirely at eleven wavelengths. This paper presents new results obtained on the crater Aristarchus using a heuristic method for the calibration of the near infrared (NIR) data set. We computed band ratios and we extracted spectra using a telescopic spectrum as reference. A new ~4¿10 km olivine rich area has been identified on the southeastern rim of the crater, in addition to a smaller olivine rich area previously reported. The olivine to pyroxene ratio exceeds 6 in this new zone. This demonstrates the uniqueness of the Clementine NIR data set in discriminating olivine from pyroxene on the lunar surface, with implications for magmatic processes in the lunar mantle and crust. ¿ 1999 American Geophysical Union