Graphite is a stone found within certain metamorphic layers.
Graphite is flammable on contact with magma but will never melt, meaning graphite on fire makes an excellent long-burning flame - a single boulder will burn for about nine and a half months before being consumed. This quality has applications in some fire-based traps.
In real life, graphite is used for pencil "lead".
comes from metamorphism of sedimentary rocks
[ENVIRONMENT_SPEC:GNEISS:CLUSTER_SMALL:100]gneiss can come from shale (sed.) or granite (ign.)