Crystals of Sr3TaGa3Si2O14 (STGS) with ordered langasite structure have been grown using the Czochralski CZ method along the [1 (1) over bar 0] axis. The as-grown crystals exhibit high optical quality and structure perfection. Giant optical rotation was observed by polarized microscope. Optical transmission was measured at various wavelengths between crossed polarizer. Optical activities were obtained by TU1900 UV-Vis spectrophotometer and found STGS crystals showed large values of rho. (C) 2003 Elsevier B.V. All rights reserved.