Ponencia presentada en el XIX Congreso Internacional de Acústica (ICA2007), Madrid, 2-7 Sep 2007.-- PACS: 43.35.Cg.The natural stone industry plays an important role in construction sector activity, and due to this fact the accurate knowledge of the physico-mechanical properties of this kind of materials is indispensable for the configuration of their quality standards. In this work we have optimized an acoustic technique, based on the measurement of the fundamental mode resonance frequency of the longitudinal wave, to determine Young's modulus in different granite variety specimens. The equipment employed was an Erudite MK3 test system (CNS Farnell) working in the range 1 to 100 kHz. The resonance frequencies obtained ranged from 4 to 10 kHz, depending on the granite variety. Based on these resonance frequencies, we obtained values of the longitudinal wave velocities ranging from 2500 to 6000 m/s and of the dynamic Young's modulus from 20 to 100 GPa. We also compared the dynamic modulus results with the static Young's modulus obtained by destructive techniques, and analysed its relationship with other significant mechanical properties.This work was partially supported by the Consejería de Educación, Ciencia y Tecnología of the Junta de Extremadura (Spain), R&D Project PR03B021, and the R&D Spanish National Plan – Project DPI2005-00124.Peer reviewed