Pierre de Volvic

The stone of Volvic is a volcanic stone which was very much used in constructions in particular in the surroundings of Clermont-Ferrand and of Riom (Auvergne - France). It has a light gray color with gray-dark almost black.

“It is not known if the stone of Volvic is black because it is Jansenist or Jansenist because it is black”. (Alexandre Vialatte in Low-Auvergne , 1936.)

It comes in most of the mines and careers close to the commune of Volvic (Puy-de-Dôme, France).

Geology

The stone of Volvic is a trachy- Andésite. It comes from cast from the Puy from Nugère. This volcano knew a rather complicated volcanology there is 11 000 years. He amongst other things lived an episode of the Strombolian type effusive which gave rise to castings trachyandesite from where it is extracted.

It is a stone of color dark gray with many small bubbles and Feldspath. It resists freezing, with the chemicals. It presents weak a Dilation coefficient. All these characteristics make of it a material interesting for construction.

Exploitation

The stone of Volvic, as its name indicates it, comes from careers close to the commune auvergnate to Volvic. It was probably exploited for a very long time. Its rise goes back to the construction of the cathedral of Clermont-Ferrand to the XIII {{E}} century.

It was initially exploited in mines under-terraines. With the XIX {{E}} century, the exploitation changed and became an exploitation with open sky what made it possible to increase the extracted quantities. During the XIXe century and the XX {{E}} century the exploitation was mechanized. The extraction of the stone of Volvic employed 1 500 people between the two world wars. It since strongly decreased.

Use

The characteristics of the stone of Volvic make of it a very good construction material for the buildings. It is the construction of churches at the end of the XII {{E}} century and to the XIII {{E}} century in the area clermontoises which marks the beginning of its intensive use in the towns of Low-Auvergne: Riom, Clermont-Ferrand etc It thereafter was very much used in these cities. Its dark color giving a very typical aspect to the architecture of the historical quarters of the towns of this area. Among the achievements one can see in Clermont-Ferrand, the Savaron house (1513) or the fountain of Amboise (1515).

She made new great strides thanks to the count de Chabrol-Volvic, Polytechnicien and prefect of the the Seine starting from 1812. This last made carry out many road works and used the stone of Volvic for the edges of trotoirs and other applications. Its texture and its hardness also make of it a material lending itself well to the Sculpture. It is used for many monuments. It for this reason is always used for the sculpture. One can see for example many sculptures using this material with Chapdes-Beaufort on the Chemin Fais' Art.

Its quality with respect to the temperature, its high point melting (approximately 1500°C) make that it is used for the enamelling of the stone which, request a heating with an average temperature of 960°C. The count de Chabrol-Volvic was the initiator. He used it for the plates of street with Paris. It was also used by the Michelin company for its indicating plates of roads. Even if the quantities decreased, It is always used at artistic ends or for the tables of orientations.

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