硬こう化かゴムこうかゴムじ字FuriganaMeanings1nounvulcanite; eboniteA hard, black rubber material made by vulcanizing natural rubber with a high sulfur content. Used for electrical insulation, combs, and mouthpieces.硬こう化かゴムは電でん気き絶ぜつ縁えん体たいとして使つかわれる。