Metallurgy

Shiny stones
''Some stones look shiny and colorfull, and unlike others they are not brittle and look like they can be shaped into things by hitting them instead of beeing chipped and sculpted. Maybe its worth investigating these special stones to see if we can make any use of it and find how to separate them from the regular ones they often seem to be mixed with?''

Potential Requirements

 * Have a city on a map that has copper or silver, and have at least 1-2 flint collectors (at the city with copper/silver) working. More might increase chances, unknown if stone has any factor, but it can appear with no stone gatherers working (building was placed however)

To confirm : Having a claim on a case with (Copper? OR/AND Coal?)

Info
Metallurgy is a Knowledge in YMIR. Metallurgy is the foundation for metallic tools and provides access to copper tools.