The pencil “lead” is actually a mixture of graphite and clay. More clay in the mixture makes the lead harder. A harder lead has a higher number. Pencils are numbered from 1-3 but most people use a ...

A batch of graphite has just been delivered to this pencil factory in Germany. Once it’s been thoroughly mixed with clay, it’s ready to go into production, with around 550 pounds of the stuff ...

These structural colors form due to a phenomenon known as thin-layer interference between clay and graphite, which are the two main components of pencil lead," explains Prof. Moriwaki ...

Creating different hardness' to pencils was discovered by Nicholas Jacques Conté. Mixing powdered graphite with clay and forming the mixture into rods that were then fired in a kiln. By varying ...

Unlike a standard pencil with a clay and graphite core, colored pencil sets are oil, water and wax-based. In addition, these pencils come in different sizes, quality and pigment proportions to ...