What is "ampelite"

Ampelite \Am"pe*lite\ ([a^]m"p[-e]*l[imac]t), n. [L. ampelitis, Gr. 'ampeli^tis, fr. 'a`mpelos vine.] (Min.) An earth abounding in pyrites, used by the ancients to kill insects, etc., on vines; -- applied by Brongniart to a carbonaceous alum schist. [1913 Webster] ||

n. 1 (context mineral English) An earth abounding in pyrites, used by the ancients to kill insects, etc., on vines. 2 (context mineral English) A carbonaceous alum schist.