A pencil's lead was never lead. Old texts called graphite plumbago and black lead, and the name stuck even after chemists showed in 1779 that it is carbon. Real lead is found in things like pre-1978 paint chips, fishing weights and decorated pottery, so poison centers advise people not to confuse it with pencil graphite. Graphite is an odd material: one of the softest solids and one of the best lubricants. Its carbon atoms link in six-member rings that slide easily over neighboring rings; the same element in a different crystal form, diamond, is one of the hardest solids known; a single graphite sheet rolled into a circle forms a carbon nanotube, a material studied for future technology. Pencil lines are astonishingly thin; a mathematician estimated that a soft 2B pencil leaves a layer about 20 nanometers thick, only about 143 carbon atoms deep. By his calculation one HB pencil's graphite could stretch into a line roughly 1,178 kilometers long. NPR's version of the same estimate says over 700 miles; by that count the two versions roughly agree.
Graphite comes in several natural forms that matter for industry. Flake graphite comes from regional metamorphism of shale and limestone. Amorphous graphite forms from metamorphosed coal; a small amount forms in veins by hydrothermal reactions; because that kind is crystalline, it is preferred for many electrical uses. Even some iron meteorites hold a little graphite. The date of Conté's pencil depends on what counts as the invention; one art reference dates his graded pencils to about 1790 and the patent to 1795. NPR says that in 1794 the French minister of war asked him to find a solution, and a French art-supply maker today credits the 1795 pencil of graphite and clay; each account can be right about a different step. From the late 1700s pulverized graphite was mixed with clay; a version of Conté's process is still used today, according to NPR. How a pencil's graphite is made can vary, though. Conté's method mixes clay and graphite and fires it, but an extrusion method described in a manufacturing text uses graphite and wax pushed through a mold into spaghetti-like strings, then dried in ovens.
The Wopex pencil goes further, extruding the wood-plastic body and core together. Its body is about 70 percent wood and the rest plastics and additives, and the maker says co-extrusion costs less energy and makes less waste; one reviewer, however, found it firm and light, writing more like a 2H to 4H pencil than the HB it was labeled, with a waxy core. Two pencils with the same grade label can write differently. Pencil hardness scales are not the same everywhere; the account by John Barrow describes about 20 commercial grades from 9B, the softest, to 9H, the hardest, with HB in the middle; a pencil-factory history instead describes letter grades from 6B to 9H and a number scale from 1 to 4 for common writing pencils. Exact grade ranges depend on the maker, so a grade is a convention rather than a measurement. Old pencils survive in only a few places; a photo caption in Barrow's book describes the oldest pencil in the world as found in a timbered house built in 1630; a Swiss naturalist's 1565 book included the first picture of a wooden pencil, and a drawing in it shows a graphite strip in a wooden tube. Greeks and Romans had earlier drawn faint lines on papyrus with flat pieces of lead.
One history says the first American pencils came about because war cut off English supplies. After the War of 1812 ended English imports, William Monroe's machine cut grooved slats. Joseph Dixon halved cedar cylinders to hold the core, and Eberhard Faber built New York's first pencil factory in 1861. Hymen Lipman received a patent in 1858 for putting an eraser on a pencil. Wood supply is a long-running concern. Eastern red cedar was once the premier U.S. pencil wood, and incense-cedar began as a substitute for it; one slat supplier says more incense-cedar is growing in western U.S. forests than ever, yet pencil use has declined because of cost and regulations, and it argues that incense-cedar should remain the premium choice; that is an interested party's argument, not a settled finding. The supplier also warns that some pencils sold as cedar are made from other woods that perform worse and are harvested less sustainably; this is the seller's view, not a neutral test; it has also moved its own slat making: the California company says it was the last slat maker in California before moving the work to Tianjin, China, in 2001.
In 2025 no natural graphite was mined in the United States, according to the U.S. Geological Survey. Companies used about 71,000 tons, worth an estimated $128 million, mainly for batteries, brake linings, lubricants, powdered metals, refractories and steelmaking. Pencils were not on that list, and by one estimate over 14 billion pencils are made around the world every year, as of November 2026. China was the world's leading natural graphite supplier in 2025, with an estimated 82 percent of world production, according to the U.S. Geological Survey, most of it crystalline flake. In 2025 the United States imported about 79,000 tons of natural graphite, about 73.4 percent flake and high-purity, 26.2 percent amorphous and 0.4 percent lump and chip. Batteries now drive much of the graphite trade. U.S. imports of graphite battery anode material were 43,400 tons in the first eight months of 2025, up from 28,100 tons in the same period of 2024, and China supplied 55 percent. Not all graphite sells for the same price either: in 2025 estimates put Sri Lankan lump and chip at about $2,600 per metric ton, flake at about $1,000 and amorphous at about $470.
Synthetic graphite is made by heating petroleum coke or coal-tar pitch to 2,500 to 3,000 degrees Celsius; the heat drives off other elements, and the carbon that remains links into sheets; it can be over 99 percent carbon. Back at the factory, workers check the pencils. Pencils ride a conveyor belt through every stage, workers inspect them and throw away any that look faulty, and a sample is sharpened and tested at the end; a common problem is glue that does not hold the two slats together, which is usually caught when the sandwiches are cut. The sandwich method itself is a compact piece of engineering. Graphite rods go into the grooves of one glued slat, and a second slat with empty grooves is turned over on top; the sandwich is clamped in a hydraulic press until the glue dries, and cutters then cut around the top and bottom halves, so one sandwich yields six to nine hexagonal pencils.
Because hardness comes from the clay-to-graphite ratio, grade is a choice made at the mixing stage. More clay makes a harder pencil, and more graphite makes a softer, blacker one. German makers tried different proportions after Conté and made softer and harder pencils that left darker or lighter marks; today a maker simply adjusts the ratio to set the grade. An eraser works by friction. Most erasers are rubber or vinyl, which grip graphite better than paper does, and rubbing loosens the graphite so the eraser can pick it up and shed small crumbs; before rubber, people used balled-up lumps of bread. In a mechanical pencil, twisting the cap moves a rod down a spiral and pushes the lead toward the tip; the first patent for a refillable pencil with a lead-propelling mechanism was issued in Britain in 1822.
Words to know
- nanotube: carbon tube
- plumbago: old name
- extrusion: pushing through
- amorphous: without shape
