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The compressional behaviour of natural pyrope gaet is investigated by using angle-dispersive synchrotron radiation x-ray diffraction and Raman spectroscopy in a diamond anvil cell at room temperature. The pressure-induced phase transition does not occur under given pressure. The equation of state of pyrope gaet is determined under pressure up to 25.3GPa. The bulk modulus KTO is 199 GPa, with its first pressure derivative KTO fixed to 4. The Raman spectra of pyrope gaet are studied. A new Raman peak nearly at 743cm-1 is observed in a bending vibration of the SiO4 tetrahedra frequency range at pressure of about 28GPa. We suggest that the new Raman peak results from the lattice distortion of the SiO4 tetrahedra. AH the Raman frequencies continuously increase with the increasing pressure. The average pressure derivative of the high frequency modes (650-1000cm-1) is larger than that of the low frequency (smaller than 650cm-1). Based on these data, the mode Griineisen parameters for pyrope are obtained.