Grüneisen parameter of quartz, quartzite, and fluorite at high pressures

Temperature changes caused by small rapid pressure changes have been measured for quartzite, single‐crystal quartz, and fluorite to 36 kbar. The Grüneisen parameter was then calculated from the adiabatic pressure derivative of temperature (∂T/∂P) s by use of the thermodynamic relationship γ = K s /T (∂T/∂P) s where K s is the adiabatic bulk modulus. The measurements were carried out in a piston cylinder apparatus using alcohol as a pressure transmitter. Parameter γ for quartz and quartzite slightly decreases with pressure, whereas we note a large decrease in γ for fluorite with pressure. We find values for q = −(∂ ℓn γ/∂ ln V) T of 2.0, 1.7, and 4.6 for quartz, quartzite, and fluorite, respectively.