Compressibility of synthetic Mg-Al tourmalines to 60 GPa

High-pressure single-crystal X-ray diffraction patterns on five synthetic Mg-Al tourmalines with near end-member compositions [dravite NaMg3Al6Si6O18(BO3)3(OH)3OH, K-dravite KMg3Al6Si6O18(BO3)3(OH)3OH, magnesio-foitite □(Mg2Al)Al6Si6O18(BO3)3(OH)3OH, oxy-uvite CaMg3Al6Si6O18(BO3)3(OH)3O, and olenite NaAl3Al6Si6O18(BO3)3O3OH, where □ represents an X-site vacancy] were collected to 60 GPa at 300 K using a diamond-anvil cell and synchrotron...