In the bustling streets of Europe and beyond, there’s a hidden story beneath our feet – one that spans millions of years and crosses continents. It’s the story of Belgian porphyry.
Beneath the streets of Paris, London, and even cities as far as New York and Sydney, lies a piece of Belgian history. The humble cobblestone, often overlooked by pedestrians and cyclists alike, tells a tale of geological wonder, human ingenuity, and global influence. This is the story of Belgian porphyry and how it quite literally paved the way for modern urban landscapes.
The magma beneath: a geological marvel
Imagine a time when the Earth’s surface was unrecognizable, when the land we now call Belgium was located in the southern hemisphere, part of a small, drifting continent named Avalonia. During the Silurian period, approximately 430 million years ago, volcanic activity pushed magma from deep within the Earth’s mantle, forcing it through cracks in the crust. This magma, once exposed to the surface, cooled and solidified, eventually becoming the porphyry that would pave the streets of history.
One of the most fascinating geological formations lies beneath the village of Quenast, southwest of Brussels – a solidified volcanic pipe, or “neck,” containing hexagonal columns of this ancient rock. Similar to the famous Devil’s Tower in Wyoming, this formation is a relic of a time when the earth was far more tumultuous and volatile.
Belgium’s golden age of porphyry
Fast forward to the 19th and early 20th centuries, when three Belgian villages – Quenast in Walloon Brabant, and Lessines and Bierghes in Hainaut – became the epicenters of porphyry extraction. The porphyry quarries of these regions were not just local enterprises; they were the largest sources of this unique rock in the world. The stones quarried here were exported to major cities across Europe, North America, Australia, Egypt, and South Africa.
Porphyry was prized for its exceptional hardness, resistance to erosion, and ability to withstand pressure and chemical attack, making it an ideal material for road construction, runways, and even ballast for high-speed trains. At its peak, more than 8,200 workers were employed in these quarries. They included skilled craftsmen known as cayoteux who transformed raw porphyry into perfectly shaped cobblestones that would find their way to streets across Europe and beyond. The photo below shows the cayoteux at work:
In the foreground of the photo above you can see specific quarry wagons and a turntable system (on the right) for changing their direction. Neatly stacked piles of cobblestones (pyramids) and others in the process of being shaped are arranged near the stonecutters’ shelters. In the background, the endless chain system driving the wagons to the crusher feed is visible. Below the chain conveyor is the railway with wagons carrying the crushed products leaving the crushing unit and exiting the quarry.
From cobblestones to modern infrastructure
Many of the famous cobblestones that challenge cyclists in the Paris-Roubaix race are made from Belgian porphyry, a testament to the durability and timelessness of this rock. Paris-Roubaix is arguably the hardest one-day race in the world; a 257 km slog over the rough cobbled farm roads of northern France.
Today, porphyry is primarily mined for its use in railway beds and other forms of aggregate, but its historical significance is far from forgotten. The rock that once paved the way for the growth of cities and the movement of people continues to support our modern world in new and innovative ways.
Honoring the legacy: A tribute to the “Cayoteux”
The story of Belgian porphyry is not just about geology; it’s also about the people who dedicated their lives to extracting and crafting this ancient stone. Geologists Eric Goemaere and Marina Cabidoche have captured this rich history in their book, “Du porphyre et des Hommes au Pays des Cayoteux“. This richly illustrated work pays homage to the cayoteux, whose labor transformed shapeless rock into perfectly shaped cobblestones.
The book dives deep into the history of porphyry extraction, using unpublished documents, old postcards, topographic maps, and photographs to paint a comprehensive picture of this industry. It’s a celebration of Belgium’s geological heritage and the enduring impact of its natural resources. You can order this book (20 euros + shipping costs) via gsb@naturalsciences.be
A rock-solid foundation for the future
As we walk the streets of our cities or watch cyclists battle the cobbles of Paris-Roubaix, let’s take a moment to appreciate the incredible journey of Belgian porphyry. From the fiery depths of the Earth to the surface of our roads, this remarkable rock continues to support our modern world, carrying with it the legacy of Belgian innovation and craftsmanship.
So the next time you encounter a cobblestone street, remember: you’re not just walking or cycling on a road. You’re stepping or pedaling on millions of years of geological history and centuries of human endeavor – all thanks to Belgian porphyry.
More information on Belgian porphyry
- The Museum of Porphyry in Rebecq
- A walk through the porphyry quarry in Lessines
- Visit the porphyry quarry in Quenast, Rebecq
More information on Wallonia
If you are Dutch-speaking you may be interested in the Waals Weekblad, which is a very interesting and useful weekly summary of news in Wallonia in the Dutch language. I actually discovered this news item in this newsletter. To subscribe (20 EUR per year), send an email to redactie@waalsweekblad.be.
Any questions or comments, feel free to drop me a line.
I created Discovering Belgium in 2011 to share the country’s hidden stories, fascinating places, and remarkable people. Through articles, photography, and audio walks, I share discoveries that reveal Belgium beyond the obvious. Hope you enjoy this site.
I had no idea 😮
Me neither, another secret of Belgium!
Fascinating! Thank you for sharing!
Thank you for reading! It’s one of those stories we don’t think about.
Not what I was expecting when I first glimpsed your title! My mind went to porphyria, as possibly George III’s stemmed from.
Aargh, comment went too soon! Was trying to insert the word madness. Also to say the actual subject matter was very interesting, although I curse cobbles any time I come across them. So hard to walk on!
And worse to cycle over! Yes, porphyry is a strange and uncommon word, and yet porphyria is so different
It’s full of wonders, our world, isn’t it, Denzil? It doesn’t look any fun working with that material back in the day. Excellent share, thanks!
Yes Jo, tough work with only a pickaxe and a hammer and no pneumatic drill or hightech digger!
Fascinating bit of history, Denzil!
Thanks for this very interesting story, Denzil. It’s incredible to think of all the continents we know now being all one huge land mass so very long ago. We always find cobblestone streets interesting and not the easiest to walk on. I can’t imagine how uncomfortable it would be to ride for 257 km over them.
Yes. As if a cycle race of that distance isn’t already tough enough!
Hi Denzil — there’s still quite a few streets in Manhattan and other East Coast cities paved with Belgian block (which the locals will often call cobblestones) but I have no idea if they shipped these over by the boatload, or if they were locally made. The ones in upstate NY seem to be granite, so they may’ve been local stone cut to the Belgian style. this is a very interesting post. I never thought of the massive industry behind paving hundreds or thousands of miles of roads this way.
Over here they still make the pavements with flat stones (not bumpy cobbles) rather than tarmac or concrete as they are easier to dig up and replace when necessary for new cabling etc.