The Collaborative International Dictionary
stinkstone
Anthraconite \An*thrac"o*nite\, n. [See Anthracite.] (Min.) A coal-black marble, usually emitting a fetid smell when rubbed; -- called also stinkstone and swinestone.
Wiktionary
stinkstone
n. (context mineralogy English) One of the varieties of calcite, barite, and feldspar, which emit a foetid odour on being struck.