The IEEE Standard 442 'Guide for Soil Thermal Resisitvity Measurement' provides a procedure to measure the thermal resistivity of the soil and values of the thermal resistivity $ρ$ for some materials.

Symbol
$M_{\mathrm{IEEE}}$
Unit
-
Related
$\rho_{\mathrm{4}}$
Choices
Material
 
Thermal resistivity
K.m/W
Quartz grains0.11
Granite grains0.26
Limestone grains0.45
Sandstone grains0.58
Mica grains1.7
Water1.65
Organic wet4.0
Organic dry7.0
Air40.0