A series of experiments was carried out in order to determine the elemental concentration of a sample doped with Cr3+, and to elucidate the nature of the energy transfer process between the Cr3+ and Nd3+ ions in lanthanum lutetium gallium garnets. Elemental concentrations were determined using the instrumental neutron activation and X-ray fluorescence techniques. Nature of the energy transfer was studied by obtaining the spectral data on the single doped samples with Cr3+ and Nd3+, and on the double doped sample with both ions. These data include absorption, luminescence, excitation spectra and pulsed excitation. The Cr --> Nd transfer efficiency, eta, was quantitatively determined to be 0.59 at room temperature. (C) 2000 Elsevier Science B.V. All rights reserved.