The Day Aluminum Became Cheaper Than Silver

At the apex of the Washington Monument, a small pyramid of aluminum gleamed in the December sun. The year was 1884, and the nine-inch capstone was the largest single piece of aluminum ever cast. It cost $225 — more than a laborer's annual wages — and was displayed at Tiffany's in New York before being hoisted into place. At the time, aluminum was a precious metal, priced above silver, reserved for royalty and ceremonial spectacle. Napoleon III had commissioned aluminum cutlery for his most honored guests; lesser visitors ate with gold.

The Metal That Refused to Let Go

Aluminum is the third most abundant element in the Earth's crust, locked in clay, shale, and the reddish ore called bauxite. But its atoms cling to oxygen with extraordinary tenacity. For decades, chemists could only coax tiny buttons of the metal from its ore using complex, costly reactions involving potassium or sodium. The yield was minuscule, the process perilous. In 1852, a pound of aluminum sold for $550; by 1880, improved methods had brought it down to $16 — still a luxury. The Washington Monument's capstone represented the summit of what was possible: a scientific trophy, not a structural material.

Two Young Men, One Solution

The breakthrough came not from an established laboratory but from two men in their early twenties, working 3,500 miles apart, unaware of each other. In Oberlin, Ohio, Charles Martin Hall, a recent graduate, had been experimenting in a woodshed behind his family home since his teens. He built his own batteries, cast his own crucibles, and breathed the fumes of fluorine compounds. On February 23, 1886, he passed a powerful electric current through a molten bath of cryolite — a rare mineral from Greenland — dissolved with alumina. At the bottom of the carbon-lined crucible, silvery globules of aluminum collected.

Simultaneously, in Gentilly, France, Paul Héroult, son of a tanner, ran the same experiment in his father's factory. He, too, used cryolite and electricity. He, too, succeeded on February 23. Neither knew the other existed. The Hall-Héroult process, as it would be called, was brutally simple: dissolve aluminum oxide in molten cryolite, apply current, collect pure metal at the cathode. The oxygen, freed from its death grip on the aluminum, rose to the carbon anodes and burned away as carbon dioxide.

The Missing Ingredient

The process was elegant, but it had a voracious appetite. Producing one pound of aluminum required seven kilowatt-hours of electricity — a staggering demand in an age of gaslight and steam. Hall realized the economics only worked where power was cheap and abundant. He found it at Niagara Falls. In 1895, the Pittsburgh Reduction Company (later Alcoa) began operation there, harnessing the cataract's fury. Within a year, the price of aluminum fell to $2 a pound. By 1900, it was 30 cents. The metal that had crowned a monument now flowed in ingots.

First Flight

The Wright brothers were among the first to grasp the implication. In 1903, their Flyer needed an engine light enough to lift itself. No manufacturer would build one; cast iron was too heavy, steel too dense. The brothers turned to their mechanic, Charlie Taylor, who cast the engine block and crankcase from an aluminum-copper alloy in a Dayton bicycle shop. The four-cylinder engine weighed 179 pounds and produced 12 horsepower — just enough. On December 17, the Flyer stayed aloft for 12 seconds. Aluminum had earned its wings.

War and Peace

World War I turned the trickle into a flood. Germany, cut off from traditional metals, developed Duralumin — an aluminum-copper-magnesium alloy that could be heat-treated to twice the strength of pure aluminum. It framed Zeppelins and, later, the first all-metal aircraft. By World War II, American plants were producing 800 million pounds a year. The B-24 Liberator contained half a ton of aluminum; the P-51 Mustang's skin was stretched over aluminum ribs.

After the war, the capacity remained. The automotive industry, slow to adapt, finally embraced the metal in the 1960s: aluminum engine blocks, transmission cases, wheels. The 1981 DeLorean DMC-12 wore stainless steel skin, but its backbone was an aluminum space frame — a "birdcage" of extruded sections welded into a rigid, lightweight skeleton. Today, the average car contains 450 pounds of aluminum. The Ford F-150, America's best-selling vehicle, shed 700 pounds when its body went aluminum in 2015.

The Pyramid's Shadow

The Washington Monument's capstone still sits at 555 feet, uncorroded after 140 winters. Its surfaces, once mirror-bright, have dulled to a soft gray — the invisible oxide layer that forms instantly in air, sealing the metal beneath. It is the same self-healing skin that protects every aluminum can, every aircraft fuselage, every window frame. The pyramid cost the equivalent of $6,000 today. The aluminum in a single 747 airframe would buy 200,000 such pyramids at current prices.

Hall died wealthy in 1914, leaving his fortune to Oberlin College. Héroult died poor in 1914, his patents entangled in French bureaucracy. Their process, unchanged in principle, still produces every kilogram of primary aluminum on Earth — 70 million metric tons a year. The woodshed in Oberlin is preserved on campus. The cryolite mine in Greenland is exhausted; synthetic cryolite replaced it. But the electricity still flows, and the metal still pools at the cathode, silent and gray, the most abundant metal finally set free.

This is one episode in a much longer story. For the full account of the history of aluminum, read “Material Revolutions: How New Materials Reshaped Design and Industry” by Andrew Stevens on MixCache.com.