The Collaborative International Dictionary
Helvine
Helvine \Hel"vine\, Helvite \Hel"vite\, n. [L. helvus of a light bay color.] (Min.) A mineral of a yellowish color, consisting chiefly of silica, glucina, manganese, and iron, with a little sulphur.
Wiktionary
helvine
n. (context mineral English) helvite.