A conductivity sensor is disclosed. The conductivity sensor includes an oscillator for providing an input signal and a reactive circuit having an induction coil, a capacitive element, and a resistive element connected in parallel. The induction coil is adapted to be placed adjacent to a specimen. The conductivity sensor further includes a control circuit for driving the reactive circuit to resonance when the induction coil is placed adjacent to the specimen. The reactive coil is configured to provide an output signal having a parameter representative of the conductivity of the specimen when the reactive circuit is at resonance. The induction coil may include a first conductive element that spirals outward to an external perimeter and a second conductive element operably connected to the first conductive element. The second conductive element spirals inward from the external perimeter staggered relative to the first conductive element.