graphite

English graphite was borrowed from German Graphit, coined by mineralogist A. G. Werner in 1789, from Ancient Greek γράφω (gráphō, "to write").

The word was created directly for the mineral in 1789, naming it for its most obvious use — leaving a mark when you write with it.

It shares its root with any word built on Greek γράφω, the verb "to write" — the same root that gives English words ending in -graph.