What pencil is actually made of ?
We usually call the black thing of pencil as a lead. The lead helps us to write. But actually it is not a lead. It is made up of a graphite which in turn is a type of Carbon. The work Graphite in Greek means "to write". So, it is named as graphite. To go all geologist on you, plumbago is a naturally occurring hexagonally organised carbon crystalline form. Diamonds are formed when high pressures and temperatures are applied to graphite. Naturally, pencils, brake linings, and batteries are just a few applications for natural graphite.
Why Graphite is referred to as Lead ?
The ancient Romans utilised a stylus, which is one of the first types of writing implements. This lead-based stylus pen was the forerunner to the ones we use today with our smartphones and other gadgets. And regrettably, that is the reason the pencil material is known as lead. When graphite was discovered in Cumbria, England in the 1500s, people believed that it was a type of lead, which is another reason why we refer to it as lead today. It was later discovered that there was no association because chemistry was still in its infancy.
The process of making pencils then changed from sawing graphite blocks into sticks to inserting graphite rods into wooden sleeves. Much later, in 1790, it was discovered that mixing graphite with clay and kiln-firing it may change the hardness of graphite pencil lead. And there, my friends, is the history of the number 2 lead pencil.