To examine scintillation response of piezoelectric crystals the 241Am 5.5 MeV α-ray excited emission spectra of langasite family crystals, LGS (La3Ga5SiO14), LNGA (La3Nb0.5Ga5.3Al0.2O14) and LTGA (La3Ta0.5Ga5.3Al0.2O 14) were measured. Dominating emission bands were observed at 378 nm for LGS, 556 nm for LNGA and 425 nm for LTGA. X-ray excited radioluminescence intensity of these crystals was quantitatively compared with BGO standard scintillator. Photoluminescence 2D-spectra were measured as well and compared with radioluminescence ones. In LTGA also photoluminescence decays were measured for two dominant contributing emission centers. Observed emission bands within 300-360 nm and beyond 400 nm most probably belong to self-trapped or trapped excitons and lattice defects, respectively.