The use of nanomechanical resonators for chemical and bioagent detection has attracted a large amount of interest in recent years, since the mass noise floor scales directly with the mass of the resonator for a given frequency stability. In order for this technology to be applied to hand-held units, the resonators should ideally be integrated with the oscillator and counter electronics, have high-Q and high frequency stability in air, and have low-temperature sensitivity. We present a quartz-based ultrahigh-frequency resonator/oscillator technology that addresses these important issues. Miniaturized shear-mode resonators with frequencies approaching 3 GHz and f×Q products of ≫1.0×1013 Hz have been fabricated on Si using low-temperature wafer bonding and deep reactive ion quartz etching. Allan deviation levels of 1.0×10-8 for 100 s integration times have been measured for a 326 MHz Pierce oscillator design. In addition, the temperature stability matches that expected for AT-cut crystal resonators. We present preliminary selective deposition results that indicate that arrays of these oscillators could be used for highly selective and high sensitivity low-cost sensors.