{{Short description|Limestone from the Loire Valley, France}} {{Unreliable sources|date=November 2025}} {{Infobox rock | name = Tuffeau | image = Tuffeau - Chapelle-Huon.jpg | caption = ''Tuffeau'' from the Turonian at La Chapelle-Huon | category = sedimentary rock | type = Limestone | minerals = Calcite, opal, quartz, clay | usage = Architecture, sculpture }} '''Tuffeau stone''' — in French, simply '''''tuffeau''''' or '''''tufeau''''' — is a local limestone of the Loire Valley of France. It is characterized as a chalky or sandy, fine-grained limestone, white to yellowish-cream in appearance, and micaceous (containing some white flakes of mica, or muscovite). The soft stone is extracted from numerous quarries and has made a major mark on the architectural landscape of the Loire and its tributaries — especially the valley's chateaux.<ref>{{Cite book |last=Přikryl |first=Richard |url=https://www.google.com/books/edition/Natural_Stone_Resources_for_Historical_M/Er7_7EEbMfsC?hl=en&gbpv=1&pg=PA112&printsec=frontcover |title=Natural stone resources for historical monuments |last2=Török |first2=Ákos |date=2010 |publisher=Geological Society |isbn=978-1-86239-291-5 |series=Geological society special publication |location=London}}</ref>
[[File:LochesTuffeau.JPG|thumb|246x246px|Part of the enciente wall at the Château de Loches, showing ''tuffeau'' blocks of various ages and in various stages of decay.]]
== Geology == The ''tuffeau'' formed in the Mesozoic era (in the Turonian stage of the Upper Cretaceous). The Loire Valley, at that time, was on the seabed; over the millennia, the sediments that deposited on the bottom, consisting of fossilized living organisms and sand particles, under the effect of pressure underwent crystallization and cementation and formed the ''tuffeau''.<ref name=LP>{{cite journal|last=Le Port|first=Jean-Pierre|title=Le tuffeau, pierre de renaissance en Val de Loire|url=https://lasim.org/images/Articles/185-le_truffeau_pierre_de_renaissance.pdf|access-date=November 11, 2025|journal=Mines & carrières|issue=185|date=October 2011|language=fr|trans-title=The tuffeau, renaissance stone in the Loire Valley|pages=18–23}}</ref> It differs from chalk by the presence of Foraminifera and many shell remains deposited in shallow waters, between 2 and 20 meters, and subsequently agitated, as occurs near the shoreline. In contrast, true Chalk is rich in another type of shell microfossil, the coccolith, due to sediment deposition in deeper and calmer waters (about 200 meters deep).<ref name=PH>{{cite web|url=http://www.pierreheritage.co.uk/blog/tuffeau-the-french-limestone-of-the-loire-valley|title=Tuffeau - the French limestone of the Loire valley|language=en|access-date=November 11, 2025|author=Steve Turner|date=August 23, 2019|archive-date=February 27, 2021|archive-url=https://web.archive.org/web/20210227215438/https://www.pierreheritage.co.uk/blog/tuffeau-the-french-limestone-of-the-loire-valley|url-status=dead}}</ref>
There are several varieties of ''tuffeau'': white ''tuffeau'', the noblest variety, used for the construction of prestigious buildings; yellow ''tuffeau'', more sandy, used in Touraine for the construction of rural buildings; gray ''tuffeau'', with bluish reflections, used in the production of hydraulic lime.<ref name="PLAT">{{cite web|title=Le travail de la pierre de tuffeau|url=https://www.parc-loire-anjou-touraine.fr/le-territoire/culture/le-travail-de-la-pierre-de-tuffeau|access-date=November 11, 2025|language=fr|trans-title=The work of tuffeau stone}}</ref><ref name=":0">{{Cite journal |last=Beck |first=K. |last2=Al-Mukhtar |first2=M. |last3=Rozenbaum |first3=O. |last4=Rautureau |first4=M. |date=2003-09-01 |title=Characterization, water transfer properties and deterioration in tuffeau: building material in the Loire valley—France |url=https://www.sciencedirect.com/science/article/pii/S036013230300074X |journal=Building and Environment |series=Building Stone Decay: Observations, Experiments and Modeling |volume=38 |issue=9 |pages=1151–1162 |doi=10.1016/S0360-1323(03)00074-X |issn=0360-1323}}</ref><ref name=":1">{{Cite journal |last=Ali |first=Harith E. |last2=Brunetaud |first2=Xavier |last3=Beck |first3=Kevin |last4=Belayachi |first4=Naima |last5=Balawi |first5=Malek |date=2023-12-31 |title=Effect of curing conditions and formulation on the adhesive strength of stone-siporex mortar composite |url=https://www.camjol.info/index.php/NEXO/article/view/17457 |journal=Nexo Revista Científica |language=en |volume=36 |issue=06 |pages=1006–1019 |doi=10.5377/nexo.v36i06.17457 |issn=1995-9516|doi-access=free }}</ref> Tuffeau has a very low density of 1.3 g/cm<sup>3</sup>. It has a porosity that reaches 45%; compressive strength is also very low (10 MPa).<ref>{{cite journal|last1=Janvier-Badosa|first1=Sarah|last2=Brunetaud|first2=Xavier|last3=Beck|first3=Kévin|last4=Al-Mukhtar|first4=Muzahim|title=Kinetics of Stone Degradation of the Castle of Chambord in France|journal=International Journal of Architectural Heritage|date=May 2015|volume=10 |language=en|url=https://www.researchgate.net/publication/276425918|access-date=November 11, 2025|doi=10.1080/15583058.2014.971194|trans-title=Kinetics of Stone Degradation of the Castle of Chambord in France|page=33}}</ref><ref name=":0" /><ref name=":1" />
The term ''tuffeau'' is etymologically linked to tuff, to which it is not geologically related (the latter is of volcanic origin), and to tufa, similar to travertine, to which it is instead geologically similar.<ref name="PH" /> All these terms derive from the Latin ''tōphus'' or ''tōfus'' ("stone").
== Physical properties == Tuffeau has a very low density compared with many other rocks, being half as dense as granite, comparable in density with ebony, and only about 10 to 20% heavier than water. It has porosity of up to 50%, whereas that of granite is only about 1%. The compressive strength of the stone is a factor of 10 to 20 times less than that of granite.<ref name=":0" /><ref name=":1" />
== Extraction == [[File:Saumur (138) Montsoreau troglodyte.jpg|thumb|''Les troglodytes'' at Montsoreau.]] [[File:Corps caverneux.jpg|thumb|upright|left|Another example with the old town of Chinon, on the way to Saumur.]] The extraction of ''tuffeau'', which began already in the Gallo-Roman period, reached its peak in the 15th century, when, especially in Touraine and Anjou, it was extracted from the natural cliffs overlooking the rivers, mainly the Loire, thanks to which the building blocks were transported on boats.<ref name="LC">{{cite web |author=Florence Pagneux |last2=Xavier Renard |date=August 22, 2013 |title=Le tuffeau, pierre de lumière du Val de Loire |trans-title=The tuffeau, stone of light of the Loire Valley |url=https://www.la-croix.com/Ethique/Environnement/Le-tuffeau-pierre-de-lumiere-du-Val-de-Loire-2013-08-22-1001100 |access-date=November 11, 2025 |language=fr}}</ref> Over the centuries, the extraction of material created vast underground galleries, some of which several kilometers long. These artificial caves, today called ''les troglodytes'' and concentrated especially around Saumur, were long used as dwellings thanks to the constant internal temperature throughout the year.<ref name=":0" /><ref name=":1" /> [[File:Carrière de tuffeau à Bourré, Loir-et-Cher.JPG|thumb|A tuffeau mine at Bourré.]] Currently, the quarries are largely used as cellars, while some host mushroom cultivation; ''tuffeau'', after being abandoned around 1950, resumed being extracted in the 1960s, mainly for the restoration of historic buildings.<ref name="PLAT" /><ref name="LC" /><ref name="LP" />
== Use in architecture == [[File:Montrésor tuffeau.jpg|thumb|A dwelling in ''tuffeau'' at Montrésor.]] In the Loire Valley, numerous buildings, public and private, are built in ''tuffeau'', thanks to the ease of working with this material, which allows for elaborate geometries for friezes, pilasters, and capitals.<ref name=PLAT/> Among the monuments built with this material are the Château de Beaulieu near Saumur, the Château d'Ussé and the Château de la Motte d'Usseau, many worker's cottages at Longères, the Nantes Cathedral and many of the châteaux of the Loire, including those of Chambord,<ref>{{cite journal|last1=Janvier-Badosa|first1=Sarah|last2=Brunetaud|first2=Xavier|last3=Beck|first3=Kévin|last4=Al-Mukhtar|first4=Muzahim|title=Kinetics of Stone Degradation of the Castle of Chambord in France|journal=International Journal of Architectural Heritage|date=May 2015|volume=10 |language=en|url=https://www.researchgate.net/publication/276425918|access-date=November 11, 2025|doi=10.1080/15583058.2014.971194|trans-title=Kinetics of Stone Degradation of the Castle of Chambord in France|pages=3–5}}</ref> Chinon, Azay-le-Rideau, and Villandry.<ref name=PLAT/>
Being a soft stone, however, ''tuffeau'' is subject to rapid erosion by scaling or chipping, accelerated by weather conditions (humidity, temperature excursion) or environmental (presence of pollutants). For this reason, the stones must be constantly replaced with other ''tuffeau'' or with more resistant material.<ref name=":0" /><ref name=":1" /><ref>{{cite journal|last1=Janvier-Badosa|first1=Sarah|last2=Brunetaud|first2=Xavier|last3=Beck|first3=Kévin|last4=Al-Mukhtar|first4=Muzahim|title=Kinetics of Stone Degradation of the Castle of Chambord in France|journal=International Journal of Architectural Heritage|date=May 2015|volume=10 |language=en|url=https://www.researchgate.net/publication/276425918|access-date=November 11, 2025|doi=10.1080/15583058.2014.971194|trans-title=Kinetics of Stone Degradation of the Castle of Chambord in France|pages=6–7}}</ref>
== See also ==
== References == {{Reflist}}
== Bibliography == *{{cite journal|last1=Janvier-Badosa|first1=Sarah|last2=Brunetaud|first2=Xavier|last3=Beck|first3=Kévin|last4=Al-Mukhtar|first4=Muzahim|title=Kinetics of Stone Degradation of the Castle of Chambord in France|journal=International Journal of Architectural Heritage|date=May 2015|volume=10 |pages=96–105 |language=en|url=https://www.researchgate.net/publication/276425918|access-date=November 11, 2025|doi=10.1080/15583058.2014.971194}} * {{cite journal|last=Le Port|first=Jean-Pierre|title=Le tuffeau, pierre de renaissance en Val de Loire|url=https://lasim.org/images/Articles/185-le_truffeau_pierre_de_renaissance.pdf|access-date=November 11, 2025|journal=Mines & carrières|issue=185|date=October 2011|language=fr|pages=18–23}}
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Category:Building stone Category:Geologic formations of France Category:Loire Valley Category:Limestone formations Category:Cretaceous France