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Forbach Granite (german: Forbachgranit), also called Raumünzach Granite (''Raumünzach-Granit''), is a type of
granite
Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
rock that occurs in the
Northern Black Forest
The Northern Black Forest (german: Nordschwarzwald) refers to the northern third of the Black Forest in Germany or, less commonly today, to the northern half of this mountain region.
Geography
The Northern Black Forest is bounded in the north b ...
. It is part of the Northern Black Forest's granitic massif, to which Bühlertal granite and Wildbad granite also belong. Forbach granite predominantly outcrops in the counties of
Calw
Calw (; previously pronounced and sometimes spelled ''Kalb'' accordingly) is a town in the middle of Baden-Württemberg in the south of Germany, capital and largest town of the district Calw. It is located in the Northern Black Forest and is a ...
and
Rastatt
Rastatt () is a town with a Baroque core, District of Rastatt, Baden-Württemberg, Germany. It is located in the Upper Rhine Plain on the Murg river, above its junction with the Rhine and has a population of around 50,000 (2011). Rastatt was a ...
. The most important quarrying area for Forbach granite used to be the middle Murg valley near
Forbach
Forbach ( , , ; gsw, Fuerboch) is a commune in the French department of Moselle, northeastern French region of Grand Est.
It is located on the German border approximately 15 minutes from the center of Saarbrücken, Germany, with which it co ...
. Today it is only
quarried near
Raumünzach.
Forbach Granite is about 305 million years old. The stone is coarse-grained - this points to a slowly cooling of the lava / magma (at the time the formation of the stone).
Forbach Granite is a bright
mica, coloured from gray to pink. Forbach Granite includes the following minerals.
*
Alkali feldspars (up to 44 percent) have a size of up to 5 centimetre and leads to a red colour.
*
Quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
(26 percent).
*
Plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more pro ...
(20 percent)
*
Muscovite
Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula K Al2(Al Si3 O10)( F,O H)2, or ( KF)2( Al2O3)3( SiO2)6( H2O). It has a highly perfect basal cleavag ...
(5 percent)
*
Biotite (5 percent) and leads to the distinct structured texture.
*
Apatite (below 1 percent)
*
Monazite
Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. The most common species of the group is monazite-(Ce), that is, the ceriu ...
(rare)
*
Xenotime
Xenotime is a rare-earth phosphate mineral, the major component of which is yttrium orthophosphate ( Y P O4). It forms a solid solution series with chernovite-(Y) ( Y As O4) and therefore may contain trace impurities of arsenic, as well as sili ...
(rare)
Literature
* W. Dienemann und O. Burre: ''Die nutzbaren Gesteine Deutschlands und ihre Lagerstätten mit Ausnahme der Kohlen, Erze und Salze,'' Enke-Verlag, Stuttgart, 1929, p. 2
* Otto Franz Geyer, Manfred P. Gwinner: ''Geologie von Baden-Württemberg''. 3rd fully revised edition, Schweizerbart, Stuttgart, 1986, .
* Wolf-Dieter Grimm: ''Bildatlas wichtiger Denkmalgesteine der Bundesrepublik Deutschland.'' Published by the Bayerischen Landesamt für Denkmalpflege, Lipp-Verlag, Munich, 1990, , Rock no. 011.
External links
Geological Natural Monuments in the Province of Karlsruhe (''Geologische Naturdenkmale im Regierungsbezirk Karlsruhe'')(pdf, 5.6 MB)
Quarry in Raumünzach* {{Commons category-inline, Forbachgranit, Forbach Granite
South German Scarplands
Granite
Rastatt (district)
Calw (district)
Geology of Germany