A rock consists of one or more different minerals. The colour, size and shape of the mineral grains determine the appearance of the rock. Based on their origin, the rocks are divided into three main types; sedimentary, metamorphic and igneous. There are the most igneous and metamorphic rocks on the globe, they make up 90-95 percent of the earth's crust. Here are some of the most important types we have in Norway.
Magmatic rocks - A magmatic rock is formed when molten rock mass (magma) solidifies. This happens either in the earth's crust (deep rocks) in cracks in the earth's crust (passage rocks) or on the earth's surface (day rocks). Characteristics; grains and dots in the stone.
Sedimentary rocks - A sedimentary rock is formed when sediments (gravel, sand and clay) are eventually petrified. Characteristics; fossils, layering, grains, rocks that are cemented together.
Metamorphic rocks - Stones that are exposed to high pressure, high temperature and/or chemical influence, and as a result are changed, or transformed, into a new type of stone. Before the change, they are either sedimentary or magmatic. Characteristics; stripes, folds.
Granite is one of the most common rocks in Norway. The rock is often very durable and is well suited for outdoor settings. Granite is a massive deep rock, rich in quartz, and contains two feldspars (alkali feldspar and some plagioclase). It is often dotted. Important types are the Iddefjord granite, which is used for most of the sculptures in Vigelandsparken, and the Drammen granite, which is used, among other things, in the old government building in Oslo.
Trondhjemitt is a bright deep rock named after Trondheim. It goes by the trade name "white granite", but is actually a tonalite; a rock that differs from granite by containing only one type of feldspar. Trondhjemitt is well suited as a facade stone, and is used, among other things, on the vertical walls of the Oslo Opera House.
Gabbro is a deep rock with a composition similar to basalt. It is found under the seabed, but also in some places on the continents. In Norway, it is a common rock that we find in Lyngen, Sulitjelma and Jotunheimen, among others. The rock is massive, coarse-grained and either dark or white and speckled with black, often with some brown or green.
Claystone is a dense sedimentary rock, and consists of compacted and very fine-grained sediments. Clay shale can often be split into thin flakes. The rock is formed from clay and silt deposits in lakes or the sea. The water in this mud was eventually driven out by new sediments on top, and the minerals were pressed together into rock. Clay shale is found in the Oslo field and on Svalbard.
Sandstone is petrified sand, formed by sand grains being pressed together. Like ordinary sand, sandstone mainly consists of grains from the minerals quartz and feldspar, which are cemented together by quartz, calc spar or iron compounds. The color usually varies from grey-white to reddish-brown. Sandstone is not a very common rock in Norway, but can be found in several places, including in the Oslo field, in Western Norway and in Trøndelag. Sandstone is a typical reservoir rock, where oil, gas and water are found in the North Sea.
Mica schist is a metamorphic rock, consisting of quartz and mica. When mica slate contains the mineral garnet, it is called garnet mica slate. The structure is often slightly wavy and scaly. In Norway, we find mica schists along the entire Caledonian mountain range. Large quarries can be found in Hyllestad, Selbu, Saltdal and Vågå, many of which are protected cultural monuments. Has been widely used as millstone in Norway.
Mylonite is a fine-grained rock formed by plastic deformation where coarser rocks have a reduced grain size. They are often finely striated, banded and slightly folded and may have "eyes" (porphyroclasts) of strong minerals, which have not recrystallized, in a fine-grained groundmass. The rock is formed in movement zones at a depth of more than 10 km during mountain chain formation and is found in Norway in areas with thrust zones. Mylonite is important as a building material, especially for use as crushed stone.
Phyllite is a metamorphosed rock with pronounced schistosity, which splits into thin plates along flakes of mica minerals. The rock is characterized by a silky sheen on the cleavage surfaces and small grain size. Phyllite is usually greenish or grayish, but the color can vary from rust red to almost black. The dark color is due to graphite, which originates from organic residues. Phyllite is formed by low-grade regional metamorphism of clay, and is very common in Norway. Widely used as natural stone.
Marble is converted from limestone, and mainly consists of well-crystallized lime spar crystals formed at relatively high pressure and temperature over a long period of time. Marble means "shining block of stone" in Greek, and has been a favorite natural stone for buildings and sculptures since ancient times. Marble is widespread in the Caledonian mountain range, particularly in Nordland, and scattered in the bedrock in Southern Norway and the Oslo field.
Eclogite is an exotic rock dominated by red garnet and green pyroxene. Eclogite has been formed under high pressure at great depths in the earth's crust or upper mantle. Norwegian eclogites were mainly formed 400-420 million years ago, during the Caledonian mountain range folding. Found in Nordfjord and Møre and Romsdal. The rock is rare and several of the Norwegian sites are protected.
Rhombporphyry is a very rare day rock that has only been found in five places on earth. It is one of the Oslo field's signature rocks. The rock is easily recognized by the large diamond-shaped bright feldspar crystals in a greyish to reddish-brown groundmass - so-called porphyry texture. The rhombuses show us that the melt never completely finished crystallizing before the magma reached the surface. Rhomb porphyry is the twin brother of larvikite, which completely solidified below the earth's surface.
Larvikitt is named after the town of Larvik, and is widely found in Vestfold and Telemark. It is a deep rock, with a special type of feldspar that gives a characteristic blue play of colour. The rock was formed 270 million years ago, when there was strong volcanic activity in the Oslofjord. Larvikite has been named Norway's national rock and is the country's most important natural stone. It is used in many prestigious buildings around the world.
Conglomerate is a sedimentary rock consisting of rounded balls, or angular small and large stones (clusters), which are cemented together in a mass of sand, silt and clay. Both bowls and stones in conglomerate can vary greatly in rock type, shape and size. The name "conglomerate" comes from the Latin word for "mixture".
Greenstone is a metamorphic rock, which is formed by the transformation of gabbro, basalt or diabase. Greenstone contains green minerals such as chlorite, epidote and amphibole, hence the color and name. Grønnstein is particularly widespread in the Trondheim area. Greenstone is often formed from basalt, deposited in underwater volcanic eruptions approx. 500 million years ago. In Norway, traces of 9,500-year-old quarries have been found, where greenstone was extracted to make axes.
Syenite is a light deep rock that resembles granite, which has much less quartz. The rock is particularly widespread in the Oslo area, where it is often referred to as nordmarkite and can be recognized by its pale red color and small cavities. Syenite is historically one of Norway's most important natural stones, used among other things at the University of Oslo, the Storting and St. John's Church in Bergen.
Limestone is a sedimentary rock that consists of more than 50 percent carbonates, and is formed from the petrification and accumulation of lime-excreting organisms (corals, algae, etc.). The rock can vary from fine-grained to coarse-grained and often contains parts of preserved fossils. Most limestone in Norway has undergone metamorphosis and turned into marble. Completely sedimentary limestones are only found on the shelf, while weakly metamorphosed limestone occurs in the Oslo area, where they were "boiled" when granite and larvikite melt penetrated them, yet no more than that fossils are often preserved.
Quartz schist/quartzite is a hard metamorphic rock that was originally sandstone. Sandstone is transformed into quartzite through temperature and pressure. If the rock is schist-free, it is called quartz schist. Pure quartzite is usually white to gray, but can also have shades of other colors. Quartz slate is one of Norway's most important natural stone types, and is mined in Alta and Oppdal, among other places. A common rock in Norway, for example in Telemark, Bamble and by Sørfjorden, while the schist-free type occurs in the Caledonian mountain range.
Kleberstein is a metamorphosed rock, consisting mainly of hydrous minerals; talc as well as chlorite, serpentine and amphibole. The color of soapstone can vary from greenish-white to dark green, often also with rust-coloured areas. The rock is fine-grained and so soft that it can be scored with a fingernail or knife. The most famous use in Norway is for Nidaros Cathedral, but the use of soapstone in Norway goes back 2,500 years, and many old soapstone outlets are today protected as cultural monuments. There are deposits of soapstone in all counties, except Vestfold and Vest-Agder.
Gneiss is one of Norway's most common rock types. It is a medium- to coarse-grained metamorphic rock, and has the same composition as granite, but with a characteristic striated or wavy texture. Gneiss is the dominant rock type in bedrock areas, which was formed more than a billion years ago.
Anortositt er en dypbergart bestående nesten utelukkende av plagioklas. Anortositt er grovkornet, ofte lys brun til grå, men kan også være hvit. Anortositt fra Rogaland har flott fargespill kalt labradorisering, som gjør den vakker som fasadestein. Bergarten er relativ sjelden på jorda, men utgjør en stor del av månen. Den finnes likevel flere steder i Norge, først og fremst i Indre Sogn, rundt Egersund og i Bergens-området.
Climbada - real rock holds for climbing