vulcanite vs hard rubber

vulcanite and hard rubber both are nouns.

Word	Noun	Adjective	Verb	Adverb
vulcanite	Yes	No	No	No
hard rubber	Yes	No	No	No

As nouns, vulcanite and hard rubber are synonyms defined as:

vulcanite and hard rubber: a hard nonresilient rubber formed by vulcanizing natural rubber

Other synonyms of vulcanite include ebonite.

vulcanite (noun)	hard rubber (noun)
a hard nonresilient rubber formed by vulcanizing natural rubber	a hard nonresilient rubber formed by vulcanizing natural rubber