Shaving Brush Silvertip Fibre® - Ebonite. Delicate lines meet a strong contrast. Deep black meets strong red. The natural material ebonite does not like to be pigeonholed. It looks like marble, but it is not. In terms of colour, the hard rubber mixture, which is produced on the basis of natural rubber and sulphur, is reminiscent of ebony. The term "ebonite" is derived from the English term "ebony".