In the 16th century, a violent storm uprooted an English oak tree to reveal a freak geological anomaly: the only large-scale deposit of solid graphite ever found on Earth.
The deposit was located in Borrowdale, a valley in the Lake District. Locals quickly realized the dark substance left remarkably permanent marks, and its discovery completely transformed the way people wrote.Before the Borrowdale storm, people wrote and drew with styluses made of literal lead or silver (a technique called silverpoint). These metal tools produced faint lines and required specially treated paper. The newly discovered Borrowdale substance, which locals mistook for a form of lead and dubbed “plumbago” (Latin for lead ore), was soft, smooth, and required no special surface. This mistaken identity is why the core of a pencil is still called “lead” today.Because the Borrowdale graphite was incredibly pure and solid, it could be sawn directly into sticks. However, pure graphite is brittle and leaves a dark smear on anything it touches. To solve this, English makers began wrapping the raw sticks tightly in sheepskin or winding them with string. As the tip wore down, the user simply unwound a small section of the string to expose more graphite. Later, artisans realized they could protect the fragile core by hollowing out sticks of wood and gluing the graphite inside, creating the familiar wooden pencil.
When other graphite sources were discovered in Europe, they were full of impurities and crumbled easily. It wasn’t until 1795, when the English Crown cut off the supply of Borrowdale graphite to France during the Napoleonic Wars, that a French officer named Nicolas-Jacques Conté found a workaround. He developed a method of grinding the inferior, crumbly graphite into a fine powder, mixing it with clay, and firing it in a kiln. This process allowed manufacturers to control the hardness and darkness of the core by altering the clay-to-graphite ratio, establishing the modern grading system from 9H to 9B.
I never heard the origin of pencil leads before or thought to ask. Amazing that something so mundane would be interesting. How many other things are like it?