ebonite
noun
eb·o·nite ˈe-bə-ˌnīt 
: hard rubber especially when black
Example Sentences
Recent Examples on the Web The former features an ebonite feed and an 18-karat gold nib available in a variety of sizes. 
Nancy Olson, Forbes, 13 Sep. 2021
Nancy Olson, Forbes, 13 Sep. 2021 Word History
First Known Use
1861, in the meaning defined above