The Unleaded Pencil
Here’s a myth buster: There is no lead in pencils. Rather, the core is made up of a non-toxic mineral called graphite. The common name “pencil lead” is due to an historic association with the stylus made of lead in ancient Roman times. If you’re looking for information on potential lead exposure risks in pencils, Click here.
EARLY GRAPHITE DISCOVERIES
Graphite came into widespread use following the discovery of a large graphite deposit in Borrowdale, England in 1564. As the story goes, a passerby found bits of a shiny, black substance clinging to the roots of a fallen tree. The whole countryside was abuzz with talk about this mysterious mineral, which eventually came to be known as “plumbagoi” or, more commonly, “Blacklead.” They found it left a dark mark, making it ideal for writing and drawing, but so soft and brittle, some type of holder was required. Initially, they wrapped graphite with string. Later, the graphite was inserted into hollowed out wooden sticks. The wood-cased pencil was born!
In 1795, a French chemist named Nicholas Jacques Conté patented a new process for making graphite pencil leads. This method mixed powdered graphite and clay in a water slurry, then formed sticks which hardened in a kiln. These composite graphite-clay “leads” allowed for more efficient use of graphite and revolutionized the pencil industry. Not only did the formula reduce costs, but by adjusting the ratio of clay and graphite powder, the changing hardness allowed more control of the lightness and darkness of the graphite mark left on the paper. It’s proved a win-win for creative expressionists ever since!
GRAPHITE IN AMERICA
In 1821, Charles Dunbar (author/Henry David Thoreau’s brother-in-law) discovered a graphite deposit in New England that proved to be of a quality superior to any previously found in the United States (though not typically up to the European quality). Still, his finding spurred the U.S. pencil industry to develop writing cores close to these graphite deposits. Eventually, the Thoreau pencil factory came to be known as one of the finest makers of pencils in America.
GRAPHITE EUREKA IN SIBERIA
French merchant Jean Pierre Alibert was searching for gold in Siberian streams when he came upon some very round, very smooth pieces of pure graphite. Reasoning that they must have been carried a long distance downstream, he trekked some 270 miles until he came to the source of his discovery.
Packing in supplies by reindeer, Alibert set up a mine at this mountainous site near the Chinese border. During the first seven years of operation, the mine produced graphite of marginal quality. Then a rich and unbroken deposit of the highest-quality graphite was uncovered; a find that yielded pieces of pure ore weighing as much as 80 pounds! Pencils using Asian graphite were painted yellow as an indication of the source of the superior material in the writing core.
PENCIL CORES TODAY
Today’s graphite writing cores are a mixture of graphite and clay. By varying the graphite to clay ratio, pencil makers adjust the core “hardness”–usually identified by a number ( 2, 2-1/2 or 3) or letters ( HB,2B, H or F). Click here to learn more about the HB Scale for grading graphite leads.
Beyond graphite pencils there are other types of pencil leads used for many different purposes.
• Charcoal pencils, used primarily by artists, are another popular form of black lead pencil, made from a different form of carbon than graphite that is more like coal. These make a very dark black mark on the paper compared to even very soft graphite pencils, such as 8B.
• Color pencil leads, also used by artists and popular with children and students, are made through a similar process of creating a blend of pigment, china clay and wax that is extruded into a lead. Some basic sets of color pencils come with 12 or 24 colors per carton, but other high quality sets for art purposes include up to 120 different colors or more.
• Aquarelle or water color pencils are color leads with the added feature of being washable in water, producing an effect similar to watercolor paints.
• Cosmetic pencils are special color leads used for make-up purposes, such as eye or lip liner.
• Finally, pastel pencils are another type of color pencils that make a mark resembling chalk, looking especially beautiful on dark papers.
Click here to watch ‘Let’s Make a Pencil’ video.