Soapstone is a beautiful natural semi soft stone (it feels like soap hence the name) that has been used for centuries for decorating and engraving.
It also has the natural ability to accumulate and retain heat, radiating it for many hours even after the original heat source has ceased.
A stove surrounded or indeed built entirely from soapstone, can continue to radiate heat depending for over six hours.
This can significantly increase the overall heating efficiency of the stove allowing you to use less wood.