I was scanning sites looking for tungsten ferro rod strikers and came across the below company selling ceramic bearing blocks and had to grab one to try out. I’m amazed no one has thought of it before.
Description from seller (walkingbirdoz) on Eprey AU
Here is a double fired and glazed ceramic palm stone / bearing block for use in a fire bow drill set. This SINGLE palm stone is APPROX 35 mm across (larger size also available) Back of stone that contacts hand is unglazed and slightly textured for easy handling. Very hard wearing and durable.