Permittivities of single-crystal quartz at X band

Although fused quartz (Si02) is known to have good dielectric properties at microwave frequencies, and, although Fe3+ in quartz is a possible maser material, the principal values of the permittivity for single-crystal quartz do not appear to have been determined in the microwave region. Preliminary measurements are presented of these at X band for high-quality, colourless mineral quartz, as used for piezoelectric crystals.