Compressibility of a natural kyanite to 17.5 GPa

The compressional behaviour of a natural kyanite, (Al(1.99)Fe(0.01))SiO(5), has been investigated to about 17.5 GPa at 300 K using a diamond-anvil cell and synchrotron X-ray diffraction. The pressure-volume data fitted to the third-order Birch-Murnaghan equation of state (EoS) yield an isothermal bulk modulus (K(0T)) of 192 +/- 6 GPa and pressure derivative (K'(0T)) of 6 +/- 1. When K'(0T) is fixed as 4, the derived K(0T) is 201 +/- 2 GPa. These values are in excellent agreement with most experimental determinations in the literature. Consequently, it can be concluded that the compressibility of kyanite under high pressures has been accurately constrained. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.