Cotta Sandstone (, also called ''Mittelquader'') is found in the Elbe Valley and in its numerous tributary valleys. Its main deposit lies in the west of the

Elbe Sandstone Mountains The Elbe Sandstone Mountains, also called the Elbe Sandstone Highlands (, ; , ), are a mountain range straddling the border between the state of Saxony in southeastern Germany and the North Bohemian region of the Czech Republic, with about three-q ...

, where it runs up to the Bohemian border, ending south of

Pirna Pirna (; , ) is a town in Saxony, Germany and capital of the administrative district Sächsische Schweiz-Osterzgebirge. The town's population is over 37,000. Pirna is located near Dresden and is an important district town as well as a ''Große ...

. It is named after the village of Cotta in the borough of

Dohma Dohma is a municipality in the Sächsische Schweiz-Osterzgebirge district, in Saxony, Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the nort ...

, an area where the stone is quarried.

Formation and properties

Cotta Sandstone was formed in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

, in the Lower

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

age. It is one of the

Elbe sandstone Elbe Sandstone () describes sandstones that naturally occur in North Bohemia and those parts of Saxony within the area around Dresden. It is named after the River Elbe, which cuts through the sandstone region in a transverse valley, the ''Elbe ...

s and its colours range from whitish to grey and yellowish grey. In the south of the area Cotta Sandstone is medium-grained, whilst, in the north it is fine-grained. Around the village of Cotta itself the grain size is evenly sized at 0.1 to 0.22 millimetres and only very rarely as large as 0.3 millimetres. The rock contains the smallest elements of mica minerals (

glauconite Glauconite is an iron potassium phyllosilicate ( mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek ...

), decomposed

feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...

and carbon elements. The carbon particles are arranged in clearly recognisable veins. They occasionally resemble

marble Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or Dolomite (mineral), dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is ty ...

textures. The technical value of this natural stone varies considerably, because the quartz grains of Cotta Sandstone are frequently siliceously bonded, but it has many unevenly divided deposits of the

phyllosilicates Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dio ...

illite Illite, also called hydromica or hydromuscovite, is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandw ...

and

kaolinite Kaolinite ( ; also called kaolin) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral sheet of alumina () ...

Extraction

The stone is quarried in

(Groß-Cotta),

Bad Gottleuba-Berggießhübel Bad Gottleuba-Berggießhübel is a spa town in the district Sächsische Schweiz-Osterzgebirge in Saxony, in eastern Germany. The municipality borders the Czech Republic in the south. The municipality was formed on 1 January 1999 by the merger of ...

(in the villages of Gottleuba and Berggießhübel), Langhennersdorf, Rottwerndorf, at Neundorf and Lohmgrund south of

, in Gersdorf and

Bahretal Bahretal is a municipality in the Sächsische Schweiz-Osterzgebirge district in Saxony, Germany. It is situated in the northeastern foothills of the Ore Mountains, between Bad Gottleuba-Berggießhübel and Dohna. It consists of several small villa ...

(Ottendorf), and in the Krippenbach valley. The quarrying of

s is made technically easier because of the separation of the beds with alternating outcrops and fissures, because the fissures are vertical and the beds run roughly at right angles to them. As a result, it is possible to cut rectangular blocks of unfinished stone. The thickness of the quarry-able sandstone beds varies from a ½ to 3 metres. The thickness of the deposits of Cotta Sandstone ranges between 50 and 80 metres.

Use

General use

Formerly the sandstone quarried near Langhennersdorf, Berggießhübel and Gersdorf, which was larger-grained, was cut not only for use as building or sculpting stone, but also for millstones.Dienemann/Burre: Die nutzbaren Gesteine Deutschlands, p. 304 Today (2008) Cotta Sandstone is used for solid window and door frames,

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

work and high-profile stonemasonry. It is especially used in restoration, but also in new structures. Its most important use is for sculptures.

Gallery

File:Leipzig Reichsgericht.jpg, Reich Court building in Leipzig File:Dresden Zwinger.jpg, Dresdner Zwinger File:Berlin tu-berlin main-building 20050214 p1000596.jpg, TU Berlin File:Berlin UdK Fasanenstraße.jpg, University of Arts, Berlin, Fasanenstraße

Sources

* W. Dienemann und O. Burre: ''Die nutzbaren Gesteine Deutschlands und ihre Lagerstätten mit Ausnahme der Kohlen, Erze und Salze,'' Enke-Verlag, Stuttgart 1929. * Siegfried Grunert: ''Der Elbsandstein: Vorkommen, Verwendung, Eigenschaften''. In: Geologica Saxonica Journal of Central European Geology 52/53 (2007), p. 143-204
Digitalisat
{{Webarchive, url=https://web.archive.org/web/20120323114152/http://www.geologica-saxonica.de/52-53/01_Grunert.pdf , date=2012-03-23 )

External links

Technical data for Cotta Sandstone

References

Sandstone Elbe Sandstone Mountains Quarries in Germany