La3Ga5SiO14 (langasite, LGS) was successfully grown by the Czochralski method. The transparency range, specific heat, thermal expansion, resistivity, dielectric constants, optical damage threshold and electrooptic (EO) coefficients of langasite crystal, have been determined. The transmission spectrum showed that the UV absorption edge of the colorless crystal is about 240 mu. The EO coefficients gamma(11) and gamma(41) are measured by the interferometric method and are 2.3 and 1.8 pm/V, respectively. A new EO Q-switch was successfully designed and fabricated by using the LGS crystal. The experimental results show that the new EO Q-switch made of langasite works properly. This is the first time that an EO Q-switch has been successfully operated with LGS as an EO crystal. (C) 2003 Elsevier Science B.V. All rights reserved.