The Famous Marble from Carrara Italy
Carrara marble is known worldwide because its pure white color makes it highly sought after for sculpture and ornamental work. Perhaps most famously, Michelangelo made his David and Pietà statues out of Carrara marble. The David statue was by accident—he acquired the piece of Carrara marble when it was rejected by another artist. After that he went to Carrara and worked with cavetori (mine workers) to choose pieces for the Pietà and other sculptures.
There are a variety of different marble types from Carrara, including grey and veined marbles, but the white variety is particularly precious. This web site—by a group that gives quarry tours—explains the different marble types: https://www.carraramarbletour.it/en/culture/marble-typologies-of-marble/.
Here is a photo of the so-called Michelangelo valley that still yields the pure white marble with the highest price. Note size of equipment that gives a sense of scale of the removed blocks.
We visited a geologist friend who lives in nearby Pontremoli. Because of our interest in the marble, she arranged for a guide to take us on a quarry tour. But first we walked around the town of Carrara, which is in the flat lands just west of the Apuan Alps in the Northern Apennines near the Ligurian coast. Here is a view eastward from downtown Carrara, with the white-streaked marble mountains in the background. There are, of course, many marble statues in town to commemorate local heros.
The Duomo di Carrara, an ancient Roman-style church, is made completely of marble, both inside and out. Marble has been quarried in this region for more than 2000 years, since ancient Roman times.
Even the sidewalks are paved with marble!
What is marble? It is a rock made of calcium carbonate (CaCO3). It starts out as limestone that formed from the inorganic remains of marine organisms; it is then metamorphosed into marble by the application heat and pressure. The Carrara limestone was deposited in the Triassic Period, about 200 million years ago, and was metamorphosed much later as part of the compressional stresses involved in the collision between Europe and Africa. The region is part of the Tuscan Nappe (large recumbent fold), but the Apuan range is a fenster (window in German), where the nappe has been eroded away and the older rocks beneath have been exposed. This probably occurred during an extensional event (crust pulling apart) that occurred after the compression.
With our guide, we headed up to the foothills of the Apuan Alps to view the marble quarries. First, our guide took us to the small town of Colonnata, where everyone (at least the males) are cavetori (mine workers). Some marble sculptures show how the rock was mined in earlier times. Even our guide’s grandfather, in the 20th century, spent his life with a hammer and chisel squaring blocks so they could be more easily conveyed via oxen-pulled carts.
The miners that worked to get the blocks down off the steep slopes, using just wooden sleds and rollers, had the most dangerous job.
Today, machinery is used to make the life of miners easier and less dangerous. Still, being around multi-ton blocks retains some danger. Here is an underground mine that we could enter because it was on the weekend. They leave large pillars of marble to hold up the remaining mountain while they continue to remove large blocks.
Here is another photo of the marble mountains. The grey part is the weathered rock that has not been quarried and the white gashes are where the marble has been mined and the fresh surfaces exposed. According to our guide, there is plenty of marble available for mining to continue for many years.
When marble is pure white, it is essentially all calcium carbonate. When the limestone contained mud from the continent, not just particles from marine organisms, other elements can be found. Other elements can also be added when fluids move through the rock and create veins. An example of a famous marble with other elements is the marble used to create the astonishing Duomo di Milano. This marble was quarried from Candiglia, located in the Piedmont region in northwestern Italy. This marble has “impurities” that give it beautiful pink, green and grey colors. Here are some photos of the cathedral that show the colors of the marble. Repairs continue to be made to the cathedral and new marble is quarried and used to replace parts that have deteriorated too much.
In the interior, the Candoglia marble was inlaid with other rocks to create a spectacular floor. Even those (like me) who eventually tire of European cathedrals can get excited by the stunning impact of nature’s materials used to create a building like this.