Rock on Rock fire ignition.
Y'all may find these links to be beneficial in regards to stone on stone fire ignition. :campfire:
Article showing three sets he made stone on stone fire with.
http://wildwoodsurvival.com/survival...bww/index.html
The most helpful article I have found on flint and pyrite fire as well as char mixes. Interestingly it refers to the same book in the link above that I had been studying.
http://www.primitiveways.com/marcasi...d%20flint.html
Vid of flint and marcasite on uncharred mugwort.
http://www.primitiveways.com/Fire-by...mpression.html