Graphite-clay pencil (Conté)
Lápiz de mina de grafito y arcilla (Conté)
- Date
- 1795 · confidence medium
- Place
- Paris, Île-de-France, France
- Credited to
- Nicolas-Jacques Conté
- Field
- Knowledge & symbols
⚠️ Disputed: the sources disagree.
What it is
A lead made by mixing powdered graphite with clay and firing it in a kiln, with adjustable hardness. It solved the scarcity of pure Borrowdale graphite and allowed a scale of hardness grades.
Josef Hardtmuth in Vienna used a clay-graphite mixture around 1790, before Conté's patent; priority is debated.
What it led to
- mass-produced pencils with graded hardness
- the H and B hardness scale
- the Faber and Staedtler pencil industry