The behavior of the resonant frequencies of a quartz crystal, coated with electrodes and tabs of the same material, is investigated both theoretically and experimentally. It is pointed out that, when the thicknesses of the tab exceeds the sum of the thickness of the electrodes, the tab behaves like a resonator acting independently of the resonator determined by the conventional electrodes. In the model, which describes this phenomenon, use is made of trapped energy theory on thickness‐twist modes. The results of numerical calculations on the theoretical model developed in this paper are in excellent agreement with the results obtained form the experiments. The additional resonant frequencies created by the presence of the tab together with the resonant frequencies related to the electrodes could possibly be used in the field of simultaneous mass and temperature determination. The principle of such a method is given in the paper.