How to qualify LGT crystal for acoustic devices?

Before using any piezoelectric crystal to realize acoustic devices (sensors, transducers, actuators or ultra-stable resonators) and beyond its mechanical properties, the crystal material itself has to be characterized. Whether the very interesting properties of the LGT crystal make it the best candidate to substitute quartz crystal for frequency output devices, we must take into account the crystal quality. Indeed, applications require homogeneous crystals with reproducible physical properties.