What is the chemical composition of Bex

The Grès by Taveyanne currently closed

Perhaps you will find rounded stones, greenish tinted and speckled black and white, in the rivers or boulders of the region. It is the Grès (a type of sandstone) from Taveyanne, a sedimentary rock of volcanic origin

The Grès is one of the sedimentary rocks in which there is gravel.

The name Grès defines gravel in geology, i.e. rock formed by rock debris (sand) and erosion of the mountain ranges.

A grès can contain numerous small particles of various stones. It is then called arkose or greywacke, depending on its composition. The Grès from Taveyanne is a gravel of the greywacke type, consisting of eroded quartz particles, silicon-containing materials (rich in chlorite, albite) and various other minerals that give the rock its speckled appearance. It is said to have resulted from the erosion of mountains and volcanoes on the southern slope of the current canton of Valais during the formation of the Alps (during the collision of tectonic plates and volcanic activities). Today this phenomenon can also be found on the western side and coast of the Andes.

These sediments have settled in basins in the Tethys. The Tethys is sandwiched between the European and African plates and is getting smaller and smaller. What is left is the Mediterranean. After a few tens of thousands of million years, these sediments have compacted and settled on the ocean floor. The basins between Africa and Europe participate in the earthly impact and are plunged into the interior of the earth, where the stone is heated by several hundred degrees (which gives it its greenish color) and then crushed and pressed. Ultimately, this rock layer forms a kind of large geological cream cut, together with other rock layers that continue to be eroded over time and by glacier activity. Today this layer is located in a zone between Taveyanne - Châtillon - Le Coin (on the edge of the Diablerets) - Solalex and Frience (source: geological map of Switzerland, sheet 1285 / Diablerets), it comes from a single volcano. The name Grès von Taveyanne is also incorrectly used for flysch rocks from other regions (Savoy - Val d’Illiez); the Grès found in these rocks very often has the same history, but not the same composition, as the Grès of Taveyanne. Despite the deformation due to temperature and pressure during the impact, it is assumed that the light or dark spots originate from the erosion of volcanic rock: - the dark color, can originate from the erosion of «basaltic» rock, the lava - the light color , from the erosion of "Andesian" rock (pumice stone), products from volcanic explosives. The mixture of the two colors could mean that the volcanic activity in the region was mixed (lava flow and explosion), like at the time of the Stromboli. The layer of the Grès de Taveyanne is relatively thin (a few meters). This could mean that the erosion of the volcanic massif in the area did not last very long, only 1 to 2 million years.

Usage of Grès today:

- Walls and wall coverings
If you go for a walk in Taveyanne or Gryon, you can marvel at numerous walls in which, among other things, Grès by Taveyanne was used. Sometimes the presence of Grès seems to be left to chance, but most of the time the builder chose the stones himself and placed them meticulously.

-To hold wood shingles on the chalets
Until the industrialization and modernism of the last 50 years, the wooden shingles of the chalets in Taveyanne were held in place by bars and stones. The blocks from Grès de Taveyanne were mostly rounded and carved by nature, so it was natural to find them on the roofs of the hamlet.

- ovens and stoves
The Grès of Taveyanne, metaphorical rock (i.e. stones that have been influenced by temperature and pressure) is a very heat-resistant rock. It can store heat (thanks to its chemical composition rich in refractory minerals) and radiate it again, but not as strongly as the well-known soapstone. The Grès from Taveyanne turns slightly white when heated, but retains its lovely speckled appearance.

- Millstones
Due to its relatively hard grain, the Grès of Taveyanne used to be hewn with great care in order to make millstones from it. These millstones were in the cellars and granaries in Gryon, but not in Taveyanne, where no grain was grown.

-Art, craft
The stele in the Center Gryonnais is an example of a work of art from Grès by Taveyanne.

Grès is hewn like sandstone, even if the stone is harder and more brittle. Chisels and graver are used for the coarser and toothed irons for the finer work. The result may then be polished.
Works from Grès by Taveyanne are mostly left raw, but the result after polishing can be very impressive, with black reflections that fade the speckled aspect.

- Esoteric and medicinal healing powers
Numerous research has shown that the Grès of Taveyanne has neither esoteric nor therapeutic healing powers. Natural therapists recommend using Grès ointments for articulations.

- Further use
Apparently, sinks were also carved from Grès by Taveyanne in the past. This is amazing because the stone is very sensitive to liquids and fat.