Hi All! I live in Northern California, in the middle if the Fransician Complex, and a lot of the fossils that I encounter here are contained within very hard greywacke matrix. This stuff is incredibly well cemented together, and only becomes harder in concretions.
This hard stone has prevented me from prepping these fossils.
I'm unsure if an ascribe will work on greywacke, I've only seen references on this forum to use soft limestones and shales.
Any advice would be greatly appreciated.
-Nick