The medieval village that gave aluminum ore its name. Geologist Pierre Berthier discovered these red clay deposits in 1821. Before the Hall-Héroult process made smelting possible in 1886, aluminum was more precious than gold. Napoleon III served dinners with aluminum cutlery to impress guests.
Benh LIEU SONG, CC BY-SA 3.0, via Wikimedia Commons
The Silver from Clay
In 1821, French geologist Pierre Berthier was investigating a reddish-brown clay deposit near the village of Les Baux-de-Provence. His analysis revealed a rock rich in aluminum hydroxide, a material previously unknown to science. He named it "bauxite" after the village where he found it. This discovery marked the identification of the world's primary source of aluminum. Bauxite is not a single mineral but a sedimentary rock. It is a heterogeneous mixture of aluminum hydroxide minerals, primarily gibbsite, boehmite, and diaspore, along with iron oxides like goethite and hematite, which give the rock its reddish color.
The bauxite found at Les Baux is a specific type known as karst bauxite. This variety forms from the weathering of clay layers embedded within carbonate rocks like limestone and dolomite. Over geological time, as the surrounding limestone dissolved, the less-soluble, aluminum-rich clays were left behind and concentrated. For decades after its discovery, the Les Baux deposits were of little interest due to their high silica content and the immense difficulty of extracting pure aluminum from the ore.
From Imperial Cutlery to Industrial Metal
Before 1886, pure aluminum was exceedingly rare and difficult to produce, making it more valuable than gold. Emperor Napoleon III of France was a major proponent of the new metal, envisioning it for lightweight military armor. He heavily subsidized early production methods developed by chemist Henri Sainte-Claire Deville. The process was so costly that Napoleon III famously reserved his personal set of aluminum cutlery for his most honored guests, while others ate with gold and silver. The public first saw ingots of the exotic "silver from clay" at the Paris Exposition Universelle in 1855.
In 1886, with the simultaneous and independent invention of an efficient electrolytic extraction method by Paul Héroult in France and Charles Martin Hall in the United States. The Hall-Héroult process made aluminum production inexpensive, transforming the precious metal into a ubiquitous industrial material. This technological leap gave new life to the bauxite deposits at Les Baux. Mining began in earnest, and until 1939, France was the world's largest producer of bauxite. The local mines operated for over a century, finally ceasing operations in 1990.
The former quarries have changed the landscape of the Val d'Enfer (Valley of Hell), whose wind-carved limestone shapes were inspired Dante's Inferno. Today, the largest of these quarries, the Grands Fonds, has been repurposed. Since 2012, it has housed the Carrières de Lumières, an immersive digital art center where masterpieces are projected onto the colossal 6,000-square-meter stone walls.
💡Fun Facts
The name "bauxite" is a direct reference to the village of Les Baux-de-Provence.
Napoleon III’s most honored dinner guests were given aluminum utensils, which were more valuable than the gold and silver used by others.
Before it was a source of aluminum ore, the limestone at Les Baux was quarried by the Romans to build monuments in the nearby city of Arles.
The reddish color of most bauxite comes from iron oxides, the same compounds that give rust its color.
The Carrières de Lumières, located in a former quarry, is open almost year-round. Hours vary by season, but it typically opens around 10:00 AM and closes between 6:00 PM and 7:00 PM. Check the official website for exact times. The village of Les Baux is always open.
Admission
A fee is required for the Carrières de Lumières; booking online in advance is recommended. Access to the village of Les Baux-de-Provence is free, though parking is paid and access to the castle ruins requires a separate ticket.
Accessibility
The village of Les Baux is perched on a rocky outcrop with steep, cobbled streets. The interior of the Carrières de Lumières is flat and generally accessible. The surrounding terrain of the Val d'Enfer can be rugged.
