Thermal conductivity is an often quoted property of fired ceramic. It is important when choosing materials that need insulating properties.
When the insulating properties of ceramic components are important one needs to choose, not only an appropriate design and forming method, but use materials of low thermal conductivity.
Kyocera, for example, lists a range of thermal conductivity products. The highest is silicon carbide. Moving downward from there (more common materials that are fairly accessible to ceramic industry): alumina, mullite, cordierite, zirconia and steatite.
Kyocera low thermal conductivity ceramics