The Coesite‐Stishovite Transition in a laser‐heated diamond cell

Abstract

The coesite‐stishovite phase boundary in the temperature range 2300–2630°C was examined in a CO 2 ‐laser heated diamond anvil cell using argon as a pressure medium. Phase identification was provided by Raman spectroscopy of the temperature quenched samples at pressure. Our results suggest a coesite‐stishovite phase boundary curve described by P(GPa) = 8.1 + 0.001T(°C) in good agreement with Yagi and Akimoto's (1976) estimate at lower temperatures. The slope of this curve is less than one half that determined recently by Zhang et al. [1993, 1994] in a multi‐anvil press.