Ebonite, what is it?

Ebonite or hard rubber is obtained by vulcanizing natural rubber for prolonged periods. Ebonite may contain from 25% to 80% sulfur and linseed oil. The material has also been called vulcanite, although that name formally refers to the mineral vulcanite.

Leonardo officina italiana purchases ebonite bars from certified companies that uses 100% high grade natural rubber collected from gum trees. Usually we buy marbled ebonite in Germany and solid color ebonite in Japan (including black ebonite for feeds).

Ebonite is a type of resin that has a very long history. It is considered the first “synthetic resin” to become widely used.
In 1839, ebonite was invented by Mr. Charles Goodyear in the United States.
Ebonite is blackish brown and firm, but its main raw material is rubber. By mixing and heating rubber and sulfur, they combine and become low-elastic and very firm vulcanized rubber with an elongation percentage of approximately 3%.

When the surface of ebonite is polished, it gives a beautiful, lacquer-like gloss.
Also, with a characteristic that does not disturb tones, it is used as inner pipes of woodwind instruments.
With these characteristics, ebonite is widely used in many ways, including electrical insulation materials, premium gold or silver lacquer fountain pens, instrument mouthpieces, smoking supplies.

My opinion, Ebonite is different, warmer than other pen materials, it has a different look and texture than other materials.

For example, I like that feeling of warmth in my hands, it feels velvety to the touch and it's interesting how over time the feeling to the touch can change.

Also the weight is different, definitely more consistent than traditional resin.

Another important aspect is the durability, some old pens are still in perfect condition even if they were produced at the end of 1800, they are 100% usable thanks to the ebonite feed that increases the durability of the pens.

The only other material that comes close to feeling so good in hand, in my opinion, is vintage celluloid but on this issue there are several variables to consider, we will talk about it in the next articles.

Is Ebonite magnetic?
Iron, cobalt and steel are ferromagnetic materials which can be used to make magnet but ebonite cannot be used to make magnets.

When was hard rubber invented?
“Ebonite is a brand name for very hard rubber first obtained by Charles Goodyear by vulcanizing natural rubber for prolonged periods. For vulcanizing natural rubber he received a patent on June 15, 1844.

Has hardness and strength comparable to metal.
Provides excellent resistance against chemicals, including acid and alkali, at room temperature.


April 01, 2020 — Salvatore Matrone