It's time to sharpen your knowledge of pencil history! (Bet you can't guess what the first erasers were made of.) ...

Indeed there are. Pencil makers manufacture Nos. 1, 2, 2.5, 3, and 4 pencils—and sometimes other intermediate numbers. The higher the number, the harder the core and lighter the markings.

You could also control the lightness and darkness: “Harder pencils” contained a greater clay to graphite composition, leaving lighter marks; softer pencils left darker marks because the ratio ...

He prefers the brand’s 9000 series, which feature leads made from a combination of finely ground graphite and clay, while Krusch opts for Faber-Castell’s Pitt Pure graphite pencils (6B or 9B ...

German pencil-makers tried out different proportions of clay and graphite to achieve softer and harder pencils that made darker or lighter marks. These experiments weren't confined to Europe.

True or false: You can get lead poisoning if you’re stuck with a lead pencil. False. Lead pencils contain graphite (a form of carbon), not lead. In fact, contrary to what many people believe ...

They’re all No. 2 or HB grade, which refers to the ratio of graphite to clay in the core, determining its color and hardness. Some are presharpened, but they’re all about 7½ to 8 inches long.

8. French pencil boosters include Nicolas-Jacques Conté, who patented a clay-and-graphite manufacturing process in 1795; Bernard Lassimone, who patented the first pencil sharpener in 1828; and Therry ...