The marble’s formation occurs through a metamorphic process from sedimentary rocks, such as limestone or dolomite, which causes a recrystallization of calcium carbonate, giving rise to a mosaic of calcite or dolomite crystals.
But it is the combined action with the heat released by the magma (the molten mass that forms in the depths of the earth)
that travels up the earth’s crust to change the structure of the rocks with which it comes into contact. The small fragments of calcium carbonate are then transformed into small crystals and with the pressure and the different temperatures all the stratifications are destroyed. Thus the formation of marble takes place.
Marble in antiquity
The Greeks called it Màrmaros, the "shining stone". Its shiny and bright appearance enchanted the ancient Greeks and Romans, and even before the peoples of Mesopotamia who began to build buildings with this stone both for its beauty and its durability.
But marble was used above all for sculpture: ancient Greece was rich in quarries. The same happened in Italy, with great names that raised the art of marble sculpture: Michelangelo, Donatello, Bernini and Canova.
They used it with pleasure, because freshly quarried marble is a soft, ductile material that is easy to work with and becomes dense over time.
Originally, colored marble was considered impure, which is why monuments such as the Pantheon in Rome and the Parthenon in Athens are made entirely of white marble, the only one considered pure and perfect, the most refined. It was extracted mainly in the quarries of Luni, in Carrara, the fulcrum of marble production and trade since the times of the Roman Empire.
The formation of Carrara marble
Carrara marble on average contains 98% calcium carbonate, a small percentage of silica, residue, dolomite and magnesium oxide. The different colors and veining are the result of mineral impurities present in the rock such as clay, sand, iron oxides, silt; each slab is unique and unrepeatable.
The marble of Carrara is known throughout the world to be extremely valuable: the quarries of the Apuan Alps were already used during the Iron Age, although the actual extraction activity was born under Julius Caesar, in 45 BC or so.
For about two thousand years the marble of Carrara has been living its maximum splendor: and it is here, that the quarry of Fiammetta Vanelli is located, whose history has been linked to the extraction of marble for over two centuries.
Excavation techniques
The methods of marble excavation have changed considerably over the years, thanks to those innovations we mentioned above.
In ancient times, in fact, the cutting was done by manual techniques: the technique of the cut allowed the excavators, equipped with chisel, to create grooves in the rock, where it was more friable thanks to natural breaks or cracks. In this way a V-shaped line was obtained, forced with iron wedges to detach the piece of marble from the mountain.
Then gunpowder was invented, and the manual technique gave way to the explosion technique. Throughout the twentieth century, mines were exploded in the quarries to facilitate the detachment of pieces of marble. This is known as the varata technique.
The main problem was the loss of material during the deflagration: so more controlled explosions were used, trying not to cause a precise detachment of the marble blocks. This technique is still used today, but only to secure the quarries when it is necessary to remove material that would cause risks to workers. Through small deflagrations, unstable elements inside the quarry are removed.
Today, diamond wire is used: steel cylinders covered with diamond for industrial use, through which entire pieces of mountain are cut to obtain large blocks of marble. With the help of bulldozers, mechanical shovels and tracked excavators, transportation is also easier than in the past.
Who works in the quarries
The Quarry Chief is a mining engineer, who might not be the most experienced worker but he has in-depth knowledge of mechanical engineering with the aim of designing systems and equipment to facilitate the work of extraction. The goal is to minimize (or completely eliminate) the risks associated with working in quarries.
The marble quarryman or quarry worker, on the other hand, rises with the rising of the sun, and is responsible for the extraction and processing of marble through specific machinery.
All operations are supervised by an engineer, to ensure safety in the workplace. From ancient times to the present day, the dangers have greatly diminished thanks to the superintendence and attention of both qualified people and the quarry owners themselves.