gems, garnet, garnet properties, synthetic garnet, reference

The physical properties of the end-members of the garnet group were first predicted by Ford (1915) and later revised by Fleischer (1937), based on extrapolations from natural garnet solid solutions to the pure end-members. However, since insufficient variables had been measured to fully specify the compositions, it became important to verify these predicted properties against actual measurements. For the present study, pure synthetic end-member garnets were available. Pyrope, spessartite, and andradite were provided by the Norton Company, synthesized from pure component oxides, although the specific temperatures and pressures of synthesis were not stated. Dr. H. S. Yoder of the Geophysical Laboratory, Carnegie Institute, supplied specimens of almandite grown at 10,000 bars and 800 °C, and grossularite grown at 9,000 bars and 970 °C. Grateful acknowledgment is given to both suppliers for their generous cooperation and assistance.