Some thermal conductivity factors

Substance	$k$ ($W/m\cdot K$)
Metals
Stainless steel	$14$
Lead	$35$
Iron	$67$
Brass	$109$
Aluminium	$235$
Copper	$401$
Silver	$428$
Sandy soil
Dry	$0.30$
$50\%$ saturated	$1.80$
$100\%$ saturated	$2.20$
Clay soil
Dry	$0.25$
$50\%$ saturated	$1.18$
$100\%$ saturated	$1.58$
Other materials
Graphite
Granite	$2.1$
Water	$0.6$
Quartz	$8$
Dry soil	$0.14$
Earth's crust	$1.7$
Gases
Air (dry)	$0.026$
Helium	$0.15$
Hydrogen	$0.18$
Building materials
Polyurethane foam	$0.024$
Stone wool	$0.043$
Glass wool	$0.048$
White pine	$0.11$
Window glass	$1.0$