What is granite?
Granite is an assemblage of quartz crystals, feldspar and mica flakes. This assemblage of grains, from the Latin "granum" gave the name of granite. Keep in mind that in french, there are two spellings of the word for two different contexts: -"granit" for quarrymen and architects and "granite" for geologists
The origins of granite
Granite is an eruptive rock rising from the magmatic depths of the earth. Cracks occurring in the earth’s crust, under strong pressure of magma, the latter reaches the surface of the globe creating volcanoes. However, it is only when the magma stops its rise towards the surface that it creates granite, a kind of "aborted" volcano. Granite was formed in the Trégor 300 million years ago when a huge magma pocket was formed underground at 4 or 5 km depth, from Trébeurden to Ploumanac’h. A few hundred thousand years later, the magma was completely cooled. This long cooling has favored the formation of mineral crystals. The longer the cooling, the larger these grains of minerals. This is our granite that became visible thanks to the gradual soil erosion, thus discovering the rocks hidden in the depth of the earth.
The Trégor granite massifs
There are three different granite massifs:
The massif linking Perros-Guirec and Bréhat (the oldest)
The Plouaret massif
The massif from Ploumanac’h to Trébeurden with 3 kinds of granite: the Clarity granite (large pink to red feldspars), the blue one and the white one of the Île-Grande
A bit of history
6000 to 6500 years ago, rise of the first megaliths Ex: dolmens of the Bono Island and Trébeurden, menhir of Pleumeur-Bodou and gallery graves of Trégastel and the Île-Grande
A few millennia later, Gallic stelae of Trébeurden or Plestin-les Grèves
From the 12th to the 17th century, construction of chapels and churches Ex: Tréguier cathedral built with granite from the Île-Grande, construction of granite houses until the 20th century
19th century: industry and trade develop, construction of houses, factories, docks, lighthouses, bridges, viaducts, paving stones, ...
Exploitation of granite on the Île-Grande
The success of the granite of the Île-Grande came, first of all, from its undeniable practical aspect: because of its insular situation, the granite quarries are easy to reach and immediately available. In addition, since most islets of the Île-Grande are uninhabited, there were no any mining constraints. Finally, note the great quality and diversity of the granite of the Île-Grande. From a regional point of view, it was here that minings were most active from the second half of the 19th century to the beginning of the 20th century and these 14 hectares of quarries constitute the finest example of granite quarrying by the seaside...
From the end of the Middle Ages and during the Renaissance, the mining of granite from Île-Grande was necessary for the construction of churches but it remained marginal. It was only from 1827 that the Municipal Council, anxious to preserve the viability of the roads and to control the unauthorized mining, while benefiting from this trade, decided to legislate on the exploitation of the granite. From 1950 onwards, reefs and small islands of the archipelago were leased to operators for successive periods of 6 to 9 years. Quarrymen came from everywhere, especially from the Chausey and the Cotentin Islands. Between 1860 and 1910, the population doubled. Fifty years during which the mining of granite, about 800 tons per day, will be at its peak on the Île-Grande which became "the island of the quarrymen". Cobblestones, curbs, quay walls and more, the granite of the Île-Grande are exported to the coasts of the Channel and the Atlantic. Landed in ports such as Caen, Cherbourg, Boulogne, Dunkirk, Bordeaux or Bayonne, partly used on site, they are routed to many inland areas such as Le Havre, Rouen, Paris, Pau, Lourdes, etc ... In Brittany, It was used for the construction of the Lighthouse des Héaux at Bréhat, the viaduct of Morlaix, the lighthouse of the Triagoz, the church of Louannec, the train station and the aqueduct of Saint-Brieuc, the quay of Portrieux , the Lézardrieux viaduct and more!
Some great careers
Kastell Erek: This quarry is the most important one, both in terms of size and volume of minings. A thick wall, still visible today, was built to protect it from the entrances of the sea. The blue and gray granites were extracted from 1908 to 1979, date of the end of exploitation since the quarry will be ceded to the Bird Protection League.
Toul ar Staon: The tip of Toul ar Staon is a rocky strip on the west of the Île-Grande where the mining was intense from the beginning of the century to the end of the 1940’s. There the ruins of former gingerbread houses are still visible, transformed into a hostel bombed by the Germans during the Second World War.
Roïc Quarry: Facing the gallery grave, this quarry was endowed not only with an mining site but also with a storage area and a pruning workshop.
Brintec’h Quarry: a mining site that overflows with water when the sea is high, the Brintec’h quarry was exploited from 1930 to 1960 for its blue granite.
Ile Corbeau (Enez Vran): The island still has traces of intense exploitation of blue granite with black or gray mica, which is why a forge was built on the flat part of the site. Only the inhabitants of the Île-Grande were authorized to mine here, the only drawback being the transport of granite to a loading dock.
The Agathon West Islands: one of the largest quarries on the islands, with a railroad for loading stones. There remain the ruins of the forge and shelters. Ile Losquet: An intensive mining took place here and the island hosts today the equipments of France Telecom. Ile Fougère: chosen to supply the viaduct of Morlaix among others, there are still the remains of a wharf and buildings.
The islands of the East Morvil Island: characterized by the mining of blue granite, this island was used for the construction of the lighthouse of Héaux de Bréhat. Île Plate and the Aval Island: also famous for their blue granite. Ile Jaouen: also supplied the viaduct of Morlaix.
The transport of granite
Bricks, schooners or barges have long been the only means of transporting the granite blocks that were then loaded at low tide. When these boats could not dock, we used the "cuckoo", a kind of small barque-well that could raise 7000 kg blocks taken at high tide under the hull and thus carried the granite to largest ships. But navigation in the middle of the pitfalls was dangerous and many boats such as "Providence" or "Mathilde" beached near the coast. By 1907, a rail embankment was built by the quarrymen themselves at the current Saint-Sauveur harbor. Routed by small train from the various quarries of the Île-Grande, the granite blocks were then embarked on gabare or other boat, transported to the Leguer quay and then wheeled to the Lannion train station.
The exploitation of granite is one thing, but the dailylife of quarrymen is another. And finally, more than the industrial or artisanal aspect, it is the human resources that determine the true identity of a place or a commune. The living and working conditions of these men were very difficult. On the Île-Grande, the sons were either sailors or quarrymen, depending on their father’s choice. And for these sons, it was better to embark on a ship than to be a quarryman, a job that was harder and less popular. At the age of 12-13, they left either as a ship’s boy or apprentice-quarrymen. No matter the weather and the outside temperature, you had to go to work. It was only in case of extreme weather conditions that the quarrymen working on the islets got back home when there were too much rain, wind, and mist that prevented them from reaching their place of work. When it was really cold, the quarrymen would warm up around the hearth of the forge and drink a bowl of hot soup. It was the women who brought them the lunch when the amplitude of the tide allowed them: potatoes, bread soup, bacon, periwinkles, barnacles, and for drink brandy and "piquette", a drink made of slices of boiled apples. The quarrymen worked most at piece rates for a fee often derisory, 4 to 7 francs (exceptional maximum, applied on the Fougère island only) per day (€0.61-1.07 / £0.52-0.92 / $0.73-1.27). Not only poorly paid, the workers had to endure a large daily hour range of about 12 hours, especially during summer with the growing length of the days. Finally, risks were not negligible, tailor, splitter, polisher or blacksmith, no one was safe from an accident.
Facing these harsh working conditions, the inhabitants of the Île-Grande has a lot of reasons to be proud of the courage and merit of its quarrymen who have left traces of a memory that is still alive on every granite block.
The end of quarries
From 1914, the shortage of manpower is felt at the dawn of WWI which mobilized many men. Once the war over, the quarrymen remained in short supply, the granite demand decreased along with the wages. Few workers left the farms of the Île-Grande around 1930 to work in other quarries, including that of La Clarté, where they were better paid. On August 16, 1936 (victory of the Popular Front), the workers led a five-week strike following which they will obtain a salary increase of only 10 centimes (€0.10 / £0.086 / $0.12). There will be conflicts of interest, mostly political, but also the bitumen era that led to the final decline of quarries on the Île-Grande which mining ceased completely in 1989.