The carving quality is even more impressive given the size of the set, color of stone varies a lot based on lighting.
Seated priests are 5.5cms tall.
Several of the pieces are signed on the underside of their bases, as is an accomplishing larger carving that was purchased from the same estate.
We were told the pieces were both together in the 1950s while visiting the Mongolia/Tuva area.
Here is a related but smaller set that sold at Christies sometime ago.