France: Les Grottes Pétrifiantes which turn everyday objects into stone.

2 min read

5 years ago Adam

These limestone grottoes, located in Savonnières, France, in the heart of Touraine, turns everyday objects into stone and were used as former quarries of limestone in the Middle Ages.
Objects left for six months to a year under the mineral-rich springs of the petrifying grottoes emerge coated in a perfectly pure white layer of limestone.
At Savonnières, the infiltration groundwater is highly charged with calcium carbonate and since the mid-nineteenth century have been “tamed” to develop the petrification.
By an extraordinary alchemy, the water loaded with calcium carbonate drips slowly on objects deposited under natural waterfalls and covers them with calcite and crystals of silica. It takes about a year time before obtaining a sufficient layer of calcite, and during that year, it is necessary to move each object every 3 weeks to ensure a harmonized layer and have details preserved.
These waters also encrust rubber moulds, placed under the waterfalls, with calcite to produce beautiful bas-reliefs. The adjacent Museum of Petrifaction collects these beautiful petrified objects for public display and sale.

Historically, about 100 million years ago, in the secondary era, a shallow sea covered the region. Masses of chalks were deposited at the bottom. Once in the open air, these formed a dominant rock in the Loire Valley: the limestone “Tuffeau”. This stone, hard enough, was used to build the most elegant Castles of the Loire Valley.
Gradually invaded by water, the quarries were abandoned, so the water seeping into cracks relentlessly eroded the limestone and created an unusual world. A rare curiosity of nature first time reported by the famous potter Bernard Palissy in 1547.
Over time water, highly concentrated with calcium carbonate, has created a wonderful enchantment with all types of limestone concretions: stalactites, stalagmites, wavy and other serrated creations that cover the original rock with different colors going from pure white to deep orange.

The grottoes, located just outside the city of Tours, in addition to the collection of stalagmites and stalactites, contain also an underground lake, a Gallo-Roman cemetery, and the second cave (discovered in 1947 by three speleologists inhabitants of Tours) is embellished also with a striking and disturbing recreation of the prehistoric fauna of the primary and secondary era.