vulcanite(n = noun.substance) ebonite, hard rubber - a hard nonresilient rubber formed by vulcanizing natural rubber;
is a kind of caoutchouc, gum elastic, india rubber, natural rubber, rubber
Hard rubber produced by vulcanizing with a large proportion of sulphur. [1913 Webster]
vulcanite, n. a hard black vulcanized rubber, ebonite.
Etymology:
as VULCANIZE