![Birkenkopf](https://upload.wikimedia.org/wikipedia/commons/e/e8/Birkenkopf.jpg)
Harz granite (german: Harzer Granit, ) is found in the
Harz Mountains
The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German ...
of central Germany. It may be divided into five types, all of which were widely used as
natural stone
This is a geographical list of natural stone used for decorative purposes in construction and monumental sculpture produced in various countries.
The dimension-stone industry classifies stone based on appearance and hardness as either "granit ...
: Knaupsholz granite, Birkenkopf granite, Wurmberg granite, Königskopf granite and Ilsestein granite. The first three
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 undergro ...
s were widely used in North Germany, Belgium and the Netherlands and, later, also in
East Germany
East Germany, officially the German Democratic Republic (GDR; german: Deutsche Demokratische Republik, , DDR, ), was a country that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. In these years the state ...
. Knaupsholz granite was ''"for a long time one of the most important types of
cut stone
Ashlar () is finely dressed (cut, worked) stone, either an individual stone that has been worked until squared, or a structure built from such stones. Ashlar is the finest stone masonry unit, generally rectangular cuboid, mentioned by Vitruv ...
in the former GDR"''.
In 2009 only Knaupsholz granite was still being quarried.
Geology
The granitic
pluton
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
s of the
Harz Mountains
The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German ...
- the
Brocken
The Brocken, also sometimes referred to as the Blocksberg, is the highest peak in the Harz mountain range and also the highest peak in Northern Germany; it is near Schierke in the German state of Saxony-Anhalt between the rivers Weser and Elbe. ...
, Ramberg and Oker plutons - were formed at the end of the Harz mountain building period (the
Hercynian orogeny
The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.
Nomenclature
The name ''Variscan'', comes f ...
) during the
Late Carboniferous
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
about 300 million years ago. These
natural stone
This is a geographical list of natural stone used for decorative purposes in construction and monumental sculpture produced in various countries.
The dimension-stone industry classifies stone based on appearance and hardness as either "granit ...
s were formed when large magma intrusions in the Brocken granite massif solidified at different cooling and crystallization rates into several differently coloured granites. The Harz granites are part of the Brocken granite complex, which is the largest granite complex in the Harz with an area of . The Harzburg
gabbro
Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is che ...
-
norite
Norite is a mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite, orthopyroxene, and olivine. The name ''norite'' is derived from ''Norge'', the Norwegian name for Norway.
Norite also known as orthopyroxen ...
intrusion forms part of this complex, but has a primary chemistry similar to an
island-arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
tholeiite
The tholeiitic magma series is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma i ...
, although it shows the effects of large scale assimilation of crustal rocks.
Quarries
Among the large quarrying concerns operating before the
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
in 1938 were the firms of ''Zureck'' in
Wernigerode
Wernigerode () is a town in the district of Harz, Saxony-Anhalt, Germany. Until 2007, it was the capital of the district of Wernigerode. Its population was 35,041 in 2012.
Wernigerode is located southwest of Halberstadt, and is picturesquely s ...
(100 to 110 employees), ''Hannoversche Basaltwerke mbH'' with its branch, the Wernigerode Granite Quarries (''Granitsteinbrüche Wernigerode'', 60 to 70 employees), and ''Braunlager Granit- und Schotterwerke G.m.b.H.'' (45 employees). There were also 5 to 7 medium and 15 to 17 small businesses with a combined total of 600 employees. Their market at that time comprised the entire territory of the
German Reich
German ''Reich'' (lit. German Realm, German Empire, from german: Deutsches Reich, ) was the constitutional name for the German nation state that existed from 1871 to 1945. The ''Reich'' became understood as deriving its authority and sovereignty ...
, Belgium and the Netherlands.
In 1948, after the war, 30 to 40 quarrymen were working in the ''Braunlager Granit- und Schotterwerken'' as well as an unknown number in another firm in
Lower Saxony
Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...
. There are no exact figures for the numbers of workers in the firms of the
German Democratic Republic
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
(GDR). The Knaupsholz and Birkenkopf quarries in the GDR and the divisions of the ''Zureck'' company in Wernigerode were expropriated on 5 November 1945.
In the early 1950s, the following quarries in the Brocken granite region were listed by Sickenberg (1951): ''
Eckerloch, Schneeloch, Gebbertsberg, Wurmberg, Haserode, Wolfklippen, Großer und Kleiner Birkenkopf, Knaupsholz, Ottofels, Neustätter Hau, Forsthaus Plessenburg'' and ''Gelochter Stein''. In 1958, eight quarries were still being worked in the territory of the GDR, but only two were left in 1969 (Knaupsholz and Birkenkopf).
Knaupsholz granite
Occurrence
Knaupsholz granite was quarried in the ''Knaupsholz'' forest district near the small settlements of
Drei Annen Hohne
Drei Annen Hohne is the name of a small settlement within the municipal area of Wernigerode in Saxony-Anhalt, Germany.
The place is located about southwest of the town within the Harz mountains, on the northeastern edge of the Harz National Park. ...
and
Schierke
Schierke is a village and a former municipality in the Harz district, in the German state of Saxony-Anhalt. Since 1 July 2009, it is part of the town Wernigerode. Situated within the Harz mountain range in the valley of the river Bode, at the rim ...
, a kilometre east of
Schierke station
Schierke station (german: Bahnhof Schierke) is the railway station in the village of Schierke operated by the Harz Narrow Gauge Railways on the Brocken Railway in the Harz Mountains of central Germany. Schierke itself lies as the foot of the highe ...
in
Saxony-Anhalt
Saxony-Anhalt (german: Sachsen-Anhalt ; nds, Sassen-Anholt) is a state of Germany, bordering the states of Brandenburg, Saxony, Thuringia and Lower Saxony. It covers an area of
and has a population of 2.18 million inhabitants, making it the ...
. Knaupsholz granite was one of the most important building stones in East Germany.
Mineral content
Knaupsholz granite is grey-red in colour and coarse-grained. It contains 33.5%
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 form ...
, 45.9%
alkali feldspar
Feldspars are 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 ''plagioclase'' (sodium-calcium) feldspa ...
, 15.1%
plagioclase feldspar
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 prope ...
, 4.8%
biotite
Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more alumino ...
and
chlorite
The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous ac ...
, 0.7% ore minerals, like
magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...
,
pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
,
hematite
Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...
, and 0.7 others. The alkali feldspar crystals can be up to 18 mm across.
[Schwate, Werner (1993). ''Harzer Granit - Abbau und Verwendung: in Stein 1993']
Available online at www.baufachinformation
, accessed on 26 July 2009.
Birkenkopf granite
Occurrence
Birkenkopf granite was quarried on the Großer Birkenkopf hill south of
Hasselfelde
Hasselfelde is a town in the district of Harz, in Saxony-Anhalt, Germany. It is situated in the eastern Harz, approximately 17 km south of Wernigerode. Since 1 January 2010, it is part of the town Oberharz am Brocken. Hasselfelde has 2,390 i ...
. It is a medium-grained granite with blue-grey coloration. In the quarry 30 to 40% blocks of stone could be used for sawing and 50% of exploitable rock debris could be obtained.
The quarry closed in 2009.
Mineral composition
Birkenkopf granite contains 31.3% quartz, 42.6% alkali feldspar, 20.4% plagioclase feldspar, 5.4% biotite and chlorite as well as 0.3% ore minerals like
magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...
,
pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
and
hematite
Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...
.
Wurmberg granite
Occurrence
The quarry for Wurmberg granite was situated about 2.5 kilometres north of
Braunlage
Braunlage () is a town and health resort in the Goslar district of Lower Saxony in Germany. Situated within the Harz mountain range, south of the Brocken massif, Braunlage's main business is tourism, particularly skiing. Nearby ski resorts includ ...
and 250 metres high on the
Wurmberg
Wurmberg is a municipality in the district of Enz in Baden-Württemberg in Germany.
Geography
Wurmberg is located on the so-called Platte, a Karst mountain range in the northern Black Forest (Schwarzwald).
Municipality
The municipality Wur ...
mountain. The granite was pale red and fine to coarse-grained. The quarry has been closed since spring 1974.
Mineral composition
This granite contains 31% quartz, 42% alkali feldspar, 20% plagioclase feldspar, 7% biotite, as well as less than 1% of other minerals like
zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the r ...
,
apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...
,
rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer Polymorphism (materials science), polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest ...
, muscovite and opaque minerals.
Königskopf granite
Occurrence
Königskopf granite was extracted in a quarry near
Königskrug
Braunlage () is a town and health resort in the Goslar district of Lower Saxony in Germany. Situated within the Harz mountain range, south of the Brocken massif, Braunlage's main business is tourism, particularly skiing. Nearby ski resorts includ ...
, which closed in the 1960s. As a result of ecological restrictions it is unlikely to be reopened again. The granite is light red to intense red (flesh red) in colour.
Mineral composition
Königskopf granite contains 33% quartz, 42% orthoclase with a mineral grain size of 2 to 5 mm up to a maximum of 15 mm, 22% plagioclase feldspar, 5% biotite and 0.7% other minerals.
[
]
Ilsestein granite
Ilsestein granite was quarried on the northern boundary of the Harz on the Kleiner Birkenkopf hill near Thale
Thale () is a town in the Harz district in Saxony-Anhalt in central Germany. Located at the steep northeastern rim of the Harz mountain range, it is known for the scenic Bode Gorge stretching above the town centre.
Geography
The town is situated ...
. It was only of local significance, because it had low hardness.
Geology and occurrence
Ilsestein granite lies on the northern perimeter of the Harz and is part of the Brocken massif. It occurs in a vein-like deposit, 11 kilometres long and 2 kilometres wide. The magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
of the Ilsestein granite was probably the last magma intrusion in the Brocken complex. It is the most quartz-rich granite in the Brocken complex. Its quartz and orthoclase elements grew together. Its utility and hardness as a construction stone is reduced by the numerous geode
A geode (; ) is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the fill ...
s, up to 5 cm across.[Franke, Dietrich]
''Regionale Geologie von Ostdeutschland''
at regionalgeologie-ost.de, accessed on 27 July 2009
Use
Harz granites are weather-resistant, polishable and resistant to aggressive, chemical compounds. Their technical properties make them very suitable for outdoor use, but they are also used indoors due to their appearance.
These granites are used as solid building stones for bridge construction, walls, door lintels and window sills, staircase steps, flags, façades, gravestones and, as cobbles and hard core, for roads. Knaupsholz granite is used as stone chippings for trails in the Harz National Park
Harz National Park is a nature reserve in the German federal states of Lower Saxony and Saxony-Anhalt. It comprises portions of the western Harz mountain range, extending from Herzberg and Bad Lauterberg at the southern edge to Bad Harzburg and I ...
. In 2009, the remaining quarries at Knaupsholz and Birkenkopf (now closed) were providing granite for the following purposes:
Technical construction
Road surfaces, cobbles, walls and bridges in Lower Saxony and North Germany, Magdeburg, Hamburg and Berlin; lock construction and bank reinforcement on the Mittelland Mittelland (German, ‘middle land’) may refer to:
* Mittelland, Switzerland, a district of the canton of Appenzell Ausserrhoden, Switzerland
* Swiss Plateau (German: ''Schweizer Mittelland''), a major landscape in Switzerland
* Mittelland, part ...
and Kiel Canal
The Kiel Canal (german: Nord-Ostsee-Kanal, literally "North- oEast alticSea canal", formerly known as the ) is a long freshwater canal in the German state of Schleswig-Holstein. The canal was finished in 1895, but later widened, and links the N ...
s.
Monuments and buildings
Harz granite has been used for monuments and memorials in Buchenwald
Buchenwald (; literally 'beech forest') was a Nazi concentration camp established on hill near Weimar, Germany, in July 1937. It was one of the first and the largest of the concentration camps within Germany's 1937 borders. Many actual or su ...
, Ravensbrück and Sachsenhausen concentration camp
Sachsenhausen () or Sachsenhausen-Oranienburg was a German Nazi concentration camp in Oranienburg, Germany, used from 1936 until April 1945, shortly before the defeat of Nazi Germany in May later that year. It mainly held political prisoners ...
s; the Soviet War Memorial in Berlin's Tiergarten and the Soviet Cenotaph in Treptow; interior of the Schiller Museum in Weimar
Weimar is a city in the state of Thuringia, Germany. It is located in Central Germany between Erfurt in the west and Jena in the east, approximately southwest of Leipzig, north of Nuremberg and west of Dresden. Together with the neighbouri ...
; the mining church in Schierke; the Palace of Culture
Palace of Culture (russian: Дворец культуры, dvorets kultury, , ''wénhuà gōng'', german: Kulturpalast) or House of Culture (Polish: ''dom kultury'') is a common name (generic term) for major Club (organization), club-houses (comm ...
of the GDR; the Deutsche Bank and town hall steps in Wernigerode.
References
Sources
Mohr, Kurt (1933). ''Geologie und Mineralstätten des Harzes.'' p. 223 ff., 2nd edition, Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, {{ISBN, 3-510-65154-5
Granite
Building stone
Quarrying
Mining in the Harz