the crystal structure of pale green gem-quality olivine from Bisbee mine,Arizona, (Mg1.83Fe0.18)Si0.99O4, a=4.7608(4)a, c=5.9903(6)a, c=5.9903(4)a, V=291.49(1)a, Pbnm, Z=4 has been refined by both single-crystal and Rietveld methods to R(%) indices of 2.20 and 9.07, respectively. Comparison of site occupancies, cell dimensions, atomic coordinations, and interatomic distances/angles obtained from both methods shows that the Rietveld method produces more accurate site scattering values, cell dimension, and atomic positions than the single-crystal method. This indicates that the Rietveld method is a useful technique for the structural characterization and crystal-chemical study of powdered samples of natural minerals and synthetic materials.

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