Acronym and details: also known as ebonite and in USA as hard rubber. It is made from chemically altered natural rubber. The process involves heat and sulphur
Group: thermoset
Developed: reaction when heated with a large percentage of sulphur to make it rigid discovered in 1839; still in use in 1930s
Trade names: Vulcanite; Ebonite
Manufacturing process: compression moulding; fabrication, including turning
Cost: medium
Colour: typically black (fades to brown) but can also be red
Transparency: always opaque
Rigidity: rigid
Feel: hard
Smell: sulphurous rubbery
Other:
Typical uses: match boxes; combs; fountain pens; imitation jet jewellery; denture palates (with pigmentation to resemble gums); pipe stems
Degradation: often faded to a greyish greenish brown shade