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Conté, also known as Conté sticks or Conté crayons, are a drawing medium (carrè, esquisse or pastel) composed of compressed powdered graphite or charcoal mixed with a wax or clay base, square in cross-section. They were invented in 1795 by Nicolas-Jacques Conté, who created the combination of clay and graphite in response to the shortage of graphite caused by the Napoleonic Wars (the British naval blockade of France prevented import). Conté crayons had the advantage of being cost-effective to produce, and easy to manufacture in controlled grades of hardness.

The most famous brand is Conté a Paris (founded in 1795).

http://www.conteaparis.com/