Euclase - UV-Vis spectra Euclase Index IR-Reflectance Photoluminescence UV-Vis-NIR Light-greenish-blue euclase – (Brazil) Blue euclase – 0.22 ct – Colombia Colorless euclase - 6.15 ct crystal - Brazil Light-greenish-blue euclase – (Brazil) Cr3+ spectrum with OH vibrationnal overtones at 980 nm Blue euclase – 0.22 ct – Colombia Cr3+ spectrum, Fe3+-Fe2+ IVCT is not observed although the stone color is deep blue Colorless euclase - 6.15 ct crystal - Brazil No spectrum