Argillite is a type of fine-grained sedimentary rock that is composed mainly of clay minerals such as illite, kaolinite, and smectite. It is typically dark grey, black, or greenish in colour, and has a smooth, waxy texture.
Argillite forms from the accumulation of clay and other fine-grained particles in a low-energy depositional environment, such as a lake or swamp. Over time, the weight of overlying sediment compacts and consolidates the clay particles, forming a dense and hard rock.
Argillite has been used by indigenous peoples of the Pacific Northwest, particularly the Haida people, to carve intricate works of art, including totem poles, masks, and other ceremonial objects. The rock’s fine-grained texture and ability to hold intricate details make it a popular material for carving. Today, argillite carvings are highly prized works of art and are considered important cultural artefacts.
Arkose is a type of sedimentary rock that is made up of sand-sized grains of feldspar and other minerals, such as quartz, mica, and clay. It is often found in areas where there has been an erosion of granite, as the feldspar in granite weathers to form arkose. Arkose is typically light to medium brown in colour, with a gritty texture, and is commonly used as a building stone or for road construction. Its composition and properties make it a good material for building foundations, as it is both durable and able to resist weathering.
3. Banded iron formation
Banded iron formation (BIF) is a type of rock that is found in ancient sedimentary deposits. These rocks are characterized by alternating bands of iron oxide and chert or silica, which form in shallow marine environments.
BIFs are important because they contain some of the earliest evidence of life on Earth, as well as some of the earliest evidence of the accumulation of atmospheric oxygen. They are also an important source of iron ore, as they can contain significant amounts of iron.
BIFs formed between 3.8 and 1.8 billion years ago, during a time when the Earth’s atmosphere had very little oxygen. The iron oxide in the bands formed through the precipitation of dissolved iron in seawater, while the silica in the bands formed from the remains of ancient microorganisms.
Today, BIFs are found in many parts of the world, including Australia, Canada, and South Africa. They are an important resource for the mining industry and are used to produce iron ore for steel production.
Breccia is a type of sedimentary rock that is composed of large, angular fragments of other rocks or minerals that are cemented together by a fine-grained matrix. The fragments can range in size from pebbles to boulders and can be made up of a variety of rock types, such as granite, limestone, or sandstone. The matrix is typically composed of smaller grains of the same or a different mineral and can be made up of materials such as clay, quartz, or calcite. Breccia is formed through a process of erosion, transport, and deposition, often in a high-energy environment such as a river or landslide. Breccia can be found in a variety of geological settings, including mountain ranges, river valleys, and along fault zones. It is commonly used as a decorative stone in construction and landscaping, and can also be used as a building material.
Calcarenite is a type of sedimentary rock that is composed of calcium carbonate grains, such as shells and shell fragments. It is a form of limestone that is commonly found in marine environments, where it is formed through the accumulation and cementation of shell debris. Calcarenite can range in color from white to gray and may contain visible fossil remains. It is often used as a building material, as it is durable and resistant to weathering.
Chalk rock is a type of sedimentary rock that is composed primarily of the mineral calcite. It forms from the accumulation of microscopic marine organisms, such as plankton and coccolithophores, that produce calcium carbonate shells. Chalk rock is typically white, soft, and porous, and is often used for writing, drawing, and as a building material. It is found in many parts of the world, including the White Cliffs of Dover in England, and the Champagne region of France.
Chert is a hard and compact sedimentary rock that is often found in limestone formations. It is composed mainly of microcrystalline quartz, but may also contain small amounts of other minerals such as calcite, clay minerals, and iron oxide. Chert can range in colour from white to grey, brown, black, or red, and has a waxy, glassy or dull luster. It is a common rock type in many geological settings, including ancient sea beds, river deposits, and volcanic ash layers. Chert is often used as a source of raw material for making tools and weapons, as it can be easily shaped and has excellent resistance to wear and fracture.
Claystone is a sedimentary rock that is primarily composed of clay minerals, such as illite, kaolinite, and smectite. It is formed from the gradual compaction and cementation of fine-grained sedimentary particles, such as silt and clay, that are deposited in quiet, low-energy environments such as lakes, lagoons, and floodplains.
Claystone typically has a smooth and fine-grained texture and can range in colour from grey to brownish-red. It is relatively soft and can be easily scratched with a fingernail. Claystone is often used as a source of clay for ceramic and pottery production, as well as for construction purposes such as bricks and tiles.
In the geological record, claystone is commonly found as a part of shale formations, where it may be interbedded with other sedimentary rocks such as sandstone and limestone. It is also found in association with coal deposits, where it can form as a result of the compaction and alteration of organic-rich sediments.
Conglomerate rock is a type of sedimentary rock that is made up of rounded gravel and pebble-sized particles that have been cemented together by finer particles or minerals, such as quartz, calcite, or iron oxide. These particles can come from a variety of sources, including the erosion of other rocks, the movement of rivers, or the deposition of material by glaciers. Conglomerate rock can vary greatly in size, texture, and composition, and often contains fossils or other geological features that provide clues about the environment in which it was formed.
Coquina is a sedimentary rock composed primarily of fragments of shells, coral, and other marine debris that have been cemented together. It is typically porous, lightweight, and can vary in colour from white to yellow to pink, depending on the composition of the shells and other materials.
Coquina is found in coastal regions, particularly in areas where there are extensive deposits of marine shells and other debris. It is commonly used as a building material, particularly for homes and other structures in areas prone to hurricanes and other severe weather events, as it is relatively resistant to damage from wind and water.
Coquina rock is also used in landscaping, as it can be shaped and carved easily to create unique features and structures. It is also used in aquariums and other aquatic environments, as it can provide a natural and aesthetically pleasing habitat for marine life.
Overall, coquina rock is an important geological resource that has many practical applications and is appreciated for its natural beauty and versatility.
Diamictite is a type of sedimentary rock that is composed of a mixture of different-sized clasts, including sand, silt, and larger boulders. It is often found in glacial environments, where the movement of ice can create a chaotic mixture of sediment sizes. Diamictite can also be found in marine environments, where it is formed by the action of waves and currents. This type of rock is commonly associated with periods of rapid climate change and can provide important insights into the geological history of the Earth.
Diatomite rock, also known as diatomaceous earth, is a sedimentary rock composed of the fossilized remains of microscopic aquatic organisms called diatoms. These single-celled organisms have hard, silica-based shells that accumulate on the ocean floor and form deposits of diatomaceous earth over millions of years. The rock is light in weight, porous, and has high silica content, making it useful for a variety of industrial applications, such as filtration, insulation, and as an abrasive in polishes and toothpaste. It is also used as a natural insecticide and is found in many organic gardening products.
13. Dolomite (rock)
Dolomite, also known as Dolostone is a sedimentary rock consisting primarily of the mineral dolomite, a calcium-magnesium carbonate. It is formed by the alteration of limestone or sedimentary rocks containing high amounts of calcium and magnesium. Dolomite rock is typically white, grey, or pink in colour and has a crystalline structure that gives it a granular or grainy texture. It is commonly used as a construction material and as a source of magnesium in industrial processes. Dolomite rock is also a popular ornamental stone used for countertops, flooring, and other decorative applications.
Evaporite is a water-soluble mineral deposit formed by evaporation from an aqueous solution. It is a type of sedimentary rock that forms when mineral-rich water evaporates, leaving behind a residue of minerals. These minerals can include gypsum, halite, anhydrite, and others. Evaporite rocks can form in various environments, including salt flats, shallow marine basins, and even caves. They are typically soft and can be easily dissolved in water, making them important sources of minerals such as salt and potash. Some common examples of evaporite rocks include rock salt, gypsum, and selenite.
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start fires.
It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white or brown in colour, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually different in colour, typically white and rough in texture. The nodules can often be found along streams and beaches.
Flint breaks and chips into sharp-edged pieces, making it useful for knife blades and other cutting tools. The use of flint to make stone tools dates back hundreds of thousands of years, and flint’s extreme durability has made it possible to accurately date its use over this time. Flint is one of the primary materials used to define the Stone Age.
During the Stone Age, access to flint was so important for survival that people would travel or trade to obtain flint. Flint Ridge in Ohio was an important source of flint and Native Americans extracted the flint from hundreds of quarries along the ridge. This “Ohio Flint” was traded across the eastern United States and has been found as far west as the Rocky Mountains and south around the Gulf of Mexico.
When struck against steel, flint will produce enough sparks to ignite a fire with the correct tinder, or gunpowder used in weapons, namely the flintlock firing mechanism. Although it has been superseded in these uses by different processes (the percussion cap), or materials (ferrocerium), “flint” has lent its name as a generic term for a fire starter.
Geyserite is a form of opaline silica that is often found around hot springs and geysers. It is formed from the precipitation of dissolved silica in geothermal hot springs and geysers. It is usually white or pale in colour and has a fine-grained, porous texture. Geyserite can form in a variety of shapes and structures, including cones, terraces, and mounds, and is often associated with the formation of geysers and other hydrothermal features. It is an important geological indicator of past and present geothermal activity and can provide valuable information about the history and evolution of geothermal systems.
Greywacke is a hard, dark sandstone with poorly sorted angular grains in a compact, clay-fine matrix. Greywacke is composed of angular grains of quartz, feldspar, and other minerals that have been compacted and cemented together by silica, clay, and other minerals. The rock is typically grey in colour, hence the name greywacke. It is commonly found in mountainous and riverbed areas and is often used as a building material for retaining walls, garden features, and landscaping. It is also used in the construction of roads and bridges due to its durability and resistance to weathering. Additionally, greywacke is a popular choice for decorative purposes such as sculptures and carvings due to its unique texture and appearance.
Gritstone is a type of sedimentary rock that is characterized by its coarse, gritty texture. It is composed of small fragments of minerals, such as quartz, feldspar, and mica, that are bound together by a cementing material, such as silica or calcite. Gritstone is usually grey or brown in colour and is often used as a building material for walls, bridges, and other structures. It is also commonly used in the construction of roads and pavements. Gritstone is found in many parts of the world, including the United States, the United Kingdom, and Australia.
Itacolumite is a porous sandstone known for its flexibility. Itacolumite is a type of metamorphic rock that is composed primarily of quartz with minor amounts of mica, feldspar, and other minerals. It is known for its unusual physical properties, including extreme flexibility and the ability to bend without breaking. This unique property is due to the highly-ordered structure of the quartz grains, which allows them to slide past each other with minimal resistance. Itacolumite is often used in the construction of buildings and other structures due to its durability and resistance to weathering. It is also popular in the jewellery industry for its attractive appearance and ease of cutting and shaping. Itacolumite is found in various locations around the world, including Brazil, India, and the United States.
Jaspillite is a type of sedimentary rock that is composed of jasper and hematite. Jasper is a variety of chalcedony that is usually red, yellow, or brown in colour, while hematite is an iron oxide mineral that is often black or dark red. Jaspillite is typically found in banded iron formations, which are ancient sedimentary rocks that contain alternating layers of iron-rich minerals and chert (a type of microcrystalline silica). Jaspillite is known for its distinct red and black banded appearance, which is a result of the contrasting colours of the jasper and hematite. The rock is often used for decorative purposes, as well as for jewellery and other ornamental objects.
Laterite is a type of soil and sedimentary rock that is rich in iron and aluminium. It forms in tropical and subtropical regions where high temperatures and heavy rainfall cause the weathering of rocks and minerals. Laterite rock is typically reddish-brown in colour and has a porous and clay-like texture. It is often used as a building material due to its durability and resistance to erosion. In some areas, laterite is also used as a source of iron ore, while in others it is used for making bricks and tiles.
Lignite rock, also known as brown coal, is a type of low-grade coal that is soft and brown in colour. It is formed from the compressed and partially decayed plant material and is typically found in shallow, sedimentary rock formations. Lignite has a low heat content and is often used as a fuel source for electricity generation in power plants. However, it is also known for its high emissions of carbon dioxide and other pollutants, making it one of the least environmentally friendly types of coal.
Limestone rock is a sedimentary rock composed mainly of calcium carbonate, formed from the accumulation of fossilized marine organisms such as coral, shells, and other organic materials over millions of years. It is commonly used as a building material, in construction, and as a raw material for cement manufacturing. Limestone rock can vary in colour from white to grey, yellow, and even red, and it can be found in various geological formations all over the world. Limestone is a valuable resource due to its versatility and abundance.
Lime-rich mud or mudstone, also known as marlstone contains variable amounts of clays and silt. Marlstone is a type of sedimentary rock that is composed of a mixture of clay, sand, and calcium carbonate. It is often gray or brown in colour and is commonly found in marine or lacustrine environments. Marlstone is often used as a building material, particularly in the construction of walls, floors, and paving. It is also used as a raw material in the production of lime and cement. In addition, marlstone is a common source of fossils, which are often found preserved in the rock.
Mudstone is a type of sedimentary rock that is composed of fine-grained clay and silt-sized particles. It is often formed in low-energy environments such as swamps, lagoons, and river deltas. Mudstone is typically gray or brown in colour and has a smooth texture. It can also contain fossils and is commonly used as a source rock for oil and gas. Mudstone is not very resistant to erosion and is often found in areas where other sedimentary rocks have been weathered away.
26. Oil shale
Oil shale is a type of sedimentary rock that contains a high concentration of organic matter, such as kerogen, that can be converted into liquid hydrocarbons, similar to crude oil. Unlike conventional oil reserves, oil shale is not a liquid or a gas and must be processed through heating, fracturing, and extraction to be converted into usable petroleum products. Oil shale deposits are found in various locations worldwide, including the United States, Canada, China, and Russia. While oil shale has the potential to be a valuable source of energy, its extraction and processing can be expensive and environmentally damaging, leading to debates about its viability as a viable energy source.
Oolite is a free and open-source 3D space trading and combat simulation game, inspired by the classic 1984 game Elite. It is available for multiple platforms, including Windows, Mac, and Linux. Oolite features a vast, procedurally generated universe for players to explore, trade, and fight in, as well as a variety of ships, weapons, and upgrades to customize their gameplay experience. The game also offers modding capabilities, allowing players to create their own content and share it with others.
Phosphorite is a sedimentary rock that contains high levels of phosphate minerals. It is primarily composed of the mineral apatite, which is a major source of phosphorus for fertilizer production. Phosphorite deposits are typically found in marine environments, where the accumulation of organic material and nutrient-rich water create conditions for the formation of phosphate minerals. The largest reserves of phosphorite are located in North Africa, China, and the United States. The mining and processing of phosphorite can have significant environmental impacts, including habitat destruction and water pollution.
Sandstone is a sedimentary rock composed of sand-sized grains of mineral, rock, or organic material cemented together by various mineral materials, such as silica, iron oxide, or calcium carbonate. It is one of the most common types of sedimentary rock and is typically formed in river, ocean, or desert environments, where sand grains are deposited and compacted over time. Sandstone can vary in colour from white to red or brown and can be smooth or rough in texture. It is often used as a building material, paving stone, or decorative feature in landscaping.
Shale is a fine-grained sedimentary rock that is made up of clay minerals and small fragments of other minerals such as quartz and feldspar. It is formed from the gradual accumulation of sediment on the bottom of lakes or oceans. Shale is typically grey or black in colour and has a layered appearance, with thin parallel bands or laminations. It is a common source rock for oil and natural gas, as well as a popular material for construction and landscaping due to its durability and weather resistance.
Siltstone is a sedimentary rock that is primarily composed of silt-sized particles (grains that range from 1/16 to 1/256 millimetres in size). It forms when layers of fine-grained sediments, such as clay or silt, are compressed and cemented together over time. Siltstone is often grey, brown, or reddish in colour and can be found in a variety of environments, including riverbeds, lakeshores, and ocean floors. It is relatively soft and can be easily scratched with a knife or rock. Siltstone is commonly used as a building stone and is also an important source of oil and gas.
Sylvinite is a naturally occurring mineral composed primarily of potassium chloride (KCl) and sodium chloride (NaCl). It is a major source of potash, which is an important fertilizer ingredient. Sylvinite is typically found in underground deposits that were formed by the evaporation of ancient seas. It is often associated with other evaporite minerals such as halite, anhydrite, and gypsum. Sylvinite is mined and processed to extract the potash, which is used to improve crop yields and promote healthy plant growth. It is also used in the production of other chemicals and industrial products.
Tillite is a type of sedimentary rock that is formed from the deposition of glacial sediments. It is made up of unsorted and poorly sorted sediments that are transported by glaciers and deposited as the ice melts. The sediments may include a mixture of boulders, pebbles, sand, and clay, which are held together by a cementing material, such as ice or clay.
Tillite is typically gray, green, or brown in color and can have a banded or layered appearance. It is usually hard and compact, and can contain fossils of plants and animals that lived in the areas where the glaciers originated.
Tillite is an important rock for studying past glacial environments and climate change. The presence of tillite in a rock formation indicates that the area was once covered by glaciers and can provide insight into the conditions under which the glaciers formed and moved. It can also provide information on the past distribution of land masses and the movement of continental plates.
Travertine is a sedimentary rock that is formed from the precipitation of calcium carbonate in hot springs, geysers, and limestone caves. It is commonly found in Italy, Turkey, and the United States. The rock is typically white or light-coloured and has a porous texture with a matte finish. It is often used in architecture, such as for building facades, flooring, and wall cladding. Travertine is also used for sculptures and decorative items, such as vases and tiles. It is a popular material due to its durability and natural beauty.
Porous limestone rock formed when carbonate minerals precipitate out of ambient temperature water. Tufa rock is a type of sedimentary rock that forms from the precipitation of dissolved minerals from water. It is typically formed in areas where groundwater containing calcium carbonate (often from limestone or marble) comes into contact with the air or with another body of water. As the water evaporates or mixes with the other water source, the calcium carbonate precipitates out and forms layers of tufa.
Tufa rock can have a variety of textures and colours, ranging from porous and white to dense and grey. It is often found in natural settings, such as near hot springs, geysers, or other water sources. Tufa rock is also used as a decorative material in architecture, sculpture, and landscaping.
Turbidite rock is a type of sedimentary rock formed by the deposition of sediment transported by turbidity currents, which are underwater avalanches of sediment and water that flow downslope along the sea floor. Turbidite rocks are typically composed of alternating layers of sand, silt, and clay, and can also contain fossil remains of marine organisms.
These rocks are often found in deep ocean basins and are important sources of hydrocarbons, such as oil and gas. They are also used in the construction of buildings and roads and as decorative stones.
Turbidite rocks provide valuable information to geologists about the history of the ocean and the geological processes that have shaped the Earth’s surface. They are often used in the study of plate tectonics, sedimentology, and palaeoclimatology.
Wackestone is a mud-supported carbonate rock that contains greater than 10% grains. Wackestone is a type of sedimentary rock that is composed of tiny fragments of shell and skeletal debris of marine organisms, such as corals, foraminifera, and bryozoans, among others. The fragments are held together by a matrix of micrite, a fine-grained carbonate mud. Wackestone is usually light-coloured, fine-grained, and soft, with a porous texture. It is often found in shallow marine environments, where the water is calm and clear, and the sedimentation rate is slow. Wackestone is an important source of information for geologists and palaeontologists, as it preserves the fossils of ancient marine life and provides clues to the history of the earth’s crust.