HISTORY AND GEOLOGY OF THE OCHRE MASSIF

An origin in the seas...

230 million years ago, Provence is flooded by the seas. The sediments accumulate at the bottom and form the white limestones that will become the Mont Ventoux, the Massif du Luberon, the Sainte Victoire, the Calanques...

Around -100 million years ago, the sea covers what will become the Land of Apt. At the bottom of the water, layers of sand settle; they take on a green colour due to the formation of a clay mineral containing iron, glauconite.

... and the Tropics

Thanks to tectonic movements, the sea recedes. The climate is humid tropical. The green sands that emerge are constantly altered : some minerals, unstable under these new conditions, disappear and others appear. Gradually, green sandstones produce ochre sands, often yellow or orange, white sands and iron shield. Ochre is a natural pigment made of clay (kaolinite) and oxide-hydroxide that give the coloring that give the coloring.

The ochre sands are born and the lands of this new continent are naturally colored.

Key dates 

Jean Etienne Astier from Roussillon invents the washing and grinding of  ochre.

< 1785

 

 

1871 >

Jean Allemand called «Jean de l’ocre» is the first operator in Rustrel

Arrival of the train in Apt and  industrial development of ochres,  earthenware and candied fruit

< 1877

 

 

1895 >

Vaucluse 1rst ochre producer with 19 producers and 22,000 tonnes

Peak production and export : 60 quarries, 20 factories, 1 000 workers, 40 000 tons

< 1928

 

 

1929 >

International economic crisis and post-war generalization of Gilbert Guigou sur Apt et Gargas synthetic dyes in industry

Gilbert Guigou in Apt and Gargas takes over the Société des Ocres de France, founded in 1901

< 1974

 

 

1994 >

Creation in the Usine Mathieu in Roussillon of the Conservatoire des ocres which has become Ecomusée de l’ocre.

Opening of Mines de Bruoux Mines in Gargas

< 2009

 


 

2022 >

Since 26 years, the ochre sector has been growing from 11 industrial jobs to more than 45 tourism and cultural jobs and kept its industrial jobs.

 

The mining today

The last quarry in operation, led by the Guigou family, lies in Gargas. In its Apt factory, the Société des Ocres de France

produces and exports around 1,000 tons per year. The ochre is extracted by the following process: extraction of the sand mixture (90%) and ochre (10%), successive washes with a «cyclone», a giant centrifuge, to remove the sand so as obtain pure ochre.

Afterwards, water is drained from the basins and ochre is left to dry completely, finally the pigment is collected. Ochre is then transported to the factory for calcination: transformation by heating; usually yellow the colour turns red. Then, to obtain different hues, the mixtures of ochre sent into a grinder.

Finally, ochre is packed, ready to travel and to be used in many application.