Piezoelectric crystals with langasite structure were broadly used in high temperature sensors in recent years. The high content of gallium made these crystals much more expensive compared than quartz. A bulk single crystal of gallium-free compound Ca₃NbAl₃Si₂O₁₄ (CNAS) with langasite structure was successfully grown by Czochralski technique. The CNAS was in strong growth habits with the dimensions of 10 mm in thickness, 25 mm in width and 45 mm in length. The piezoelectric properties of CNAS were forecasted by first-principle calculation. The density measure by Archimedes method is 3.28 kg/m³. High-resolution X-ray diffraction (HRXRD) results indicate that CTAS crystals are free of low-angle boundaries. The whole set of piezoelectric, elastic and dielectric tensors were tested by the resonance method. The piezoelectric constant d₁₁ is -4.69 pC/N and d₁₄ is 3.57 pC/N. The dielectric constant ε₁₁ is 13.28 and ε₃₃ is 17.7. The electromechanical coefficient k₁₂ is 14.7% and k₂₆ is 17.2%. The comparison of experimental and theoretical results shown that the first-principles is a good tool for searching novel piezoelectric crystals. Combined with the properties of the high resistivity under high temperature, CNAS is a good candidate for high temperature application.

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