Visitors to the 1889 Exposition Universelle in Paris entered the fairgrounds under the shadow of the newly-built Eiffel Tower—a gleaming marvel of wrought iron lattice that stretched almost a thousand feet into the air. Once inside, they could gawk at a massive reconstruction of the Bastille or gasp as Annie Oakley demonstrated her legendary marksmanship in Buffalo Bill’s Wild West show.

Amidst this myriad of spectacles was a rather less dramatic—but no less influential—innovation from a Czech manufacturing company named Hardtmuth Pencil. Its latest creation was formed, as all pencils are, of a graphite core housed in a protective wooden sheath. What stood out was its color—Hardtmuth’s “luxury pencil” was painted yellow.

Prior to 1889, the highest-quality pencils were left “natural polished.” Manufacturers usually painted their pencils if they were looking to cover up imperfections in the wood. Accordingly, typical paint colors were dark: purple, red, maroon, or black.

But Hardtmuth was looking for a way to advertise the caliber of its graphite rather than its wood. “For a long time the best graphite came from the west—England, in particular,” explained Duke University professor Henry Petroski, author of The Pencil: A History of Design and Circumstance. (The very first graphite deposit was discovered in Borrowdale, England, in 1564, centuries before yellow pencils arrived on the scene.) Although the British supply of graphite eventually ran out, soon “a new and superior source was found in Siberia.”