Heat conductivity of the mineral components by phonons. Solid line: the Callaway model fitted as described in the text. Dashed line: Hofmeister (1999) model for high-temperature conductivity. Panel a: forsterite. Black circles: experimental data for total heat conductivity (including radiative contributions) of olivine with composition Fa₁₈ (from the compilation of Clauser & Huenges 1995). Crosses: data for phonon heat conductivity of forsterite from Schatz & Simmons (1972), datum for 300 K from Chai et al. (1996). The dashed line shows the reduced heat conductivity for particles of about 1 mm diameter. Panel b: enstatite. Black circles: experimental data for phonon heat conductivity of orthopyroxene from Schatz & Simmons (1972), datum for 300 K from Horai & Baldridge (1972). Panel c: diopside. Black circles: experimental data for phonon heat conductivity of orthopyroxene from Hofmeister & Yuen (2007). Black square: datum for 300 K from Horai & Simmons (1969). Panel d: plagioclase. Dashed line: fit to experimental data for heat conductivity of plagioclase given by Hofmeister et al. (2009) for the temperature rage between 300 and 1200 K.