Last May, while staying in the town of Caromb in Provence, we took a drive to visit Rousillion, the town famous for ochre pigments. The village sits atop red sand similar to what one might expect to find in Utah. The difference is that in Utah, it is red sandstone. Quite a spectacular sight even though, coming directly from Moab, it was very small in scale. That aside, it was a very instructive day.
We stumbled into the nearby village of Gargas and found Dominique at the office of the mairie. Even though it wasn't her regular day, she offered to take Nancy and I on a private tour of the ochre mines a little later in the day. We felt deeply honored. Dominique was a Spaniard who came to France as a youngster during the Spanish Civil War and she was now married to a Frenchman. Her English was a wonderful collection of French and Spanish accents. To begin with, we visited the museum dedicated to the pigment mines and saw the tools, photographs of the old miners and I especially remember a map of the mines. Like anywhere with valuable minerals underground, over time, they had a myriad of tunnels running beneath the surface and it looked to me as they left only enough to support itself from collapse.
Back in the days before WWII they used to mine the pigments just as you would any other underground mineral. They dug shafts by hand, horizontally at a cliff face, into the pigment rich earth. At first the shafts were quite small, but over time they were enlarged downward. Using small rounded shovels, they enlarged the shafts until they were too big to deal with. In the photos, you can see the marks the shovels left on the side of the tunnel walls. They have since closed up the mine shafts and put doors on them so people can't get into trouble in there. But Dominique took us into one of the shafts and it was probably 30 degrees (F) cooler inside. As you can see, the pigment strata are very thick, occuring approximatley 60 to 80 feet below the surface.
Nowadays they mine the pigment like you would mine coal in Montana, that is, by removing the overburden with large equipment. The original ore varies in color from light to deep yellow, dependent upon the quantity of iron oxide it contains. The pigment ore is taken down the road to be processed in a manner similar to what was done years ago with very few updates, just slightly larger in scale but with less human labor involved. The sand is separated from the pigment by centrifugal force, then power-washed into decantation pits where the heavier ochre sinks and the water evaporates under the sun.
Baking the pigments at high temperatures alters the chemical composition of the oxides and broadens the color range from yellows to reds, and every combination in between. When it is perfectly dry it is pulverized into a silky powder and sold for various purposes including making paints and as a benign agricultural dye, meaning to dye fertilizers, herbicides and other products put onto fields. Other uses include tints for face powders and blushes used in cosmetics, as well as pottery and ceramics.
All in all, it was a fascinating tour and I wish I could remember more information, like why the pigment occurs in Gargas and in very few other places, and the what is the chemical composition of the pigments. As always, if you know more about this subject, be sure to comment.
Unfortunately, these photos are downloading in reverse order from what they should be, so you are seeing the last part of the process first. Photos by Nancy.