DOLOMITE
CAS NO.: 16389-88-1
EC/LIST NO.: 240-440-2
Dolomite (/ˈdɒl.əˌmaɪt, ˈdoʊ.lə-/) is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO3)2.
The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite.
An alternative name sometimes used for the dolomitic rock type is dolostone.
As stated by Nicolas-Théodore de Saussure the mineral dolomite was probably first described by Carl Linnaeus in 1768.
In 1791, it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu (1750–1801), first in buildings of the old city of Rome, and later as samples collected in the mountains now known as the Dolomite Alps of northern Italy.
Nicolas-Théodore de Saussure first named the mineral (after Dolomieu) in March 1792.
Dolomite might be a good source of calcium carbonate and magnesium.
Dolomite is a common rock-forming mineral.
Dolomite is a calcium magnesium carbonate with a chemical composition of CaMg(CO3)2.
Dolomite is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble.
Limestone that contains some dolomite is known as dolomitic limestone.
Dolomite is also a common mineral in hydrothermal veins.
There Dolomite is often associated with barite, fluorite, pyrite, chalcopyrite, galena, or sphalerite.
In these veins Dolomite often occurs as rhombohedral crystals which sometimes have curved faces.
Dolomite serves as the host rock for many lead, zinc, and copper deposits.
These deposits form when hot, acidic hydrothermal solutions move upward from depth through a fracture system that encounters a dolomitic rock unit.
These solutions react with the dolomite, which causes a drop in pH that triggers the precipitation of metals from solution.
Dolomite also serves as an oil and gas reservoir rock. During the conversion of calcite to dolomite, a volume reduction occurs.
This can produce pore spaces in the rock that can be filled with oil or natural gas that migrate in as they are released from other rock units.
This makes the dolomite a reservoir rock and a target of oil and gas drilling.
Dolomite is a common rock-forming mineral.
Dolomite is a calcium magnesium carbonate with a chemical composition of CaMg(CO3)2.
Dolomite is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble.
Limestone that contains some dolomite is known as dolomitic limestone.
Dolomite is rarely found in modern sedimentary environments, but dolostones are very common in the rock record.
They can be geographically extensive and hundreds to thousands of feet thick.
Most rocks that are rich in dolomite were originally deposited as calcium carbonate muds that were postdepositionally altered by magnesium-rich pore water to form dolomite.
Dolomite is also a common mineral in hydrothermal veins.
There Dolomite is often associated with barite, fluorite, pyrite, chalcopyrite, galena, or sphalerite.
In these veins it often occurs as rhombohedral crystals which sometimes have curved faces.
Dolomite is a common mineral.
Dolomite is also known as CaMg(CO3)2 and is a type of compact limestone consisting of a calcium magnesium carbonate.
In combination with calcite and aragonite, dolomite makes up approximately 2% of the earth's crust.
The mineral was first described by and then named after the French mineralogist and geologist Deodat de Dolomieu (1750–1801).
Dolomite is a fairly soft mineral that occurs as crystals as well as in large sedimentary rock beds several hundred feet thick.
The crystals—usually rhombohedral in shape—are transparent to translucent and are colorless, white, reddish-white, brownish-white, gray, or sometimes pink.
In powdered form, dolomite dissolves readily with effervescence in warm acids.
Dolomite is calcium magnesium carbonate having the chemical formula CaMg(CO3)2.
Dolomite occurs naturally as a mineral and as a rock.
As a mineral, dolomite exists mostly as rhomboidal, sometimes prismatic, translucent or transparent, colorless or white crystals.
Small amounts of manganese, iron and other impurities give some dolomite rocks and crystals their color (gray, pink, orange, red, yellow, green or black).
Dolomite may also refer to a sedimentary rock that is at least 90% dolomite.
A limestone dolomite consists of 50% to 90% dolomite by weight.
The rock is also known as dolomitized limestone because it is thought to originate from limestone that has been transformed into a dolomite by dolomitization.
During dolomitization, the calcium in the CaCO3-rich limestone is partially replaced by magnesium to form dolomite (CaMg(CO3)2).
Dolomite rock is also known as dolostone.
In appearance, dolomite looks like the more common calcite (CaCO3), but as indicated by their chemical formulas, their chemical composition differs.
Calcite has no magnesium ions.
In March 1792, Nicolas-Théodore de Saussure named the mineral calcium magnesium carbonate as dolomite after the French mineralogist Deodat de Dolomieu.
Dolomite (MgCO3, CaCO3) is relatively inexpensive and is readily available.
Dolomite is more active if calcined and used downstream in the postgasification secondary reactor at above 800°C (Sutton et al., 2001).
The reforming reaction of tar on dolomite surface occurs at a higher rate with CO2 (Eq. (6.6)) than with steam (Eq. (6.5)).
Under proper conditions, it can entirely convert the tar.
Dolomite, however, cannot convert methane if that is to be avoided for syngas production.
Carbon deposition deactivates dolomite, which, being less expensive, may be discarded
Dolomite is a sedimentary rock composed primarily of calcium magnesium carbonate.
The word dolomite is also referred to dolomite mineral so sometimes being confused between rock and mineral.
Limestone is composed of calcium carbonate and dolomite is composed of calcium magnesium carbonate so it is thought to be originated by the post depositional alteration of limestone via magnesium rich ground water.
Dolomite consist all the properties of limestone, have same hardness, reacts with hydrochloric acid and bears the same colour (white to grey or white to light brown).
Dolomite is a form of limestone, rich in approximately equal parts of magnesium carbonate and calcium carbonate.
Dolomite is found widely throughout the world. Dolomitic limestone contains about five times as much magnesium and five eighths as much calcium as ordinary limestone.
Dolomite also contains small amounts of chlorine, phosphorus, and potassium, in addition to more than 20 other trace elements.
Dolomite long has been used as a source of calcium and magnesium for animal feeds.
Dolomite now is available in a number of dosage forms including tablets and chewable wafers, to be taken as dietary supplements.
In animal models, minerals from dolomite are well absorbed.
Research reveals no animal or clinical data regarding the use of dolomite as a magnesium and calcium supplement.
Dolomite, a type of limestone, provides valuable nutrients to plants and helps change the pH of the soil by raising it to match the plants' needs.
Dolomite's sometimes called dolomitic lime or dolomitic limestone, and provides more nutrients than straight lime.
Dolomite's often used in addition to balanced fertilizers, particularly with seeding fruit.
Dolomite is a calcium magnesium carbonate with a chemical composition of CaMg(CO3)2.
Limestone that contains some dolomite is known as dolomitic limestone.
Dolomite is a very common mineral, and is known for its saddle-shaped curved crystal aggregates.
A unique, isolated Dolomite occurrence in Eugui, Spain has provided colorless transparent crystals that resemble the Iceland Spar variety of Calcite.
The occurrence of Kolwezi, in the Congo, has produced some fascinating, cobalt-rich specimens that are a beautiful hot pink color and highly popular.
Dolomite forms in a different crystal class, differing from the Calcite group minerals.
This can be noted by the fact that Dolomite generally forms more elongated crystals than those of the Calcite group.
In addition, Dolomite never occurs in scalenohedral crystals, whereas minerals of the Calcite group do.
Dolomite is used to describe both a mineral and a rock.
The mineral is the pure form with a defined crystal structure and chemical formula, whereas dolomite rock is composed chiefly of the mineral Dolomite, but also contains impurities such as Calcite, Quartz, and feldspar.
The mineral dolomite crystallizes in the trigonal-rhombohedral system.
Dolomite forms white, tan, gray, or pink crystals.
Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions.
Unless it is in fine powder form, it does not rapidly dissolve or effervesce (fizz) in cold dilute hydrochloric acid as calcite does.
Crystal twinning is common.
Solid solution exists between dolomite, the iron-dominant ankerite and the manganese-dominant kutnohorite.
Small amounts of iron in the structure give the crystals a yellow to brown tint.
Manganese substitutes in the structure also up to about three percent MnO.
A high manganese content gives the crystals a rosy pink color.
Lead, zinc, and cobalt also substitute in the structure for magnesium.
The mineral dolomite is closely related to huntite Mg3Ca(CO3)4.
Because dolomite can be dissolved by slightly acidic water, areas where dolomite is an abundant rock-forming mineral are important as aquifers and contribute to karst terrain formation
Modern dolomite formation has been found to occur under anaerobic conditions in supersaturated saline lagoons such as those at the Rio de Janeiro coast of Brazil, namely, Lagoa Vermelha and Brejo do Espinho.
There are many other localities where modern dolomite forms, notably along sabkhas in the Persian Gulf, but also in sedimentary basins bearing gas hydrates and hypersaline lakes.
Dolomite is often thought that dolomite nucleates with the help of sulfate-reducing bacteria (e.g. Desulfovibrio brasiliensis), but other microbial metabolisms have been also found to mediate in dolomite formation.
In general, low-temperature dolomite may occur in natural supersaturated environments rich in extracelullar polymeric substances (EPS) and microbial cell surfaces.
This is likely result from complexation of both magnesium and calcium by carboxylic acids comprising EPS.
Vast deposits of dolomite are present in the geological record, but the mineral is relatively rare in modern environments.
Reproducible, inorganic low-temperature syntheses of dolomite are yet to be performed.
Usually, the initial inorganic precipitation of a metastable "precursor" (such as magnesium calcite) can easily be achieved.
The precursor phase will theoretically change gradually into a more stable phase (such as partially ordered dolomite) during periodical intervals of dissolution and re-precipitation.
The general principle governing the course of this irreversible geochemical reaction has been coined "breaking Ostwald's step rule".
High diagenetic temperatures, such as those of groundwater flowing along deeply rooted fault systems affecting some sedimentary successions or deeply buried limestone rocks allocate dolomitization.
But the mineral is also volumetrically important in some Neogene platforms never subjected to elevated temperatures.
Under such conditions of diagenesis the long-term activity of the deep biosphere could play a key role in dolomitization, since diagenetic fluids of contrasting composition are mixed as a response to Milankovitch cycles.
A recent biotic synthetic experiment claims to have precipitated ordered dolomite when anoxygenic photosynthesis proceeds in the presence of manganese(II).
A still perplexing example of an organogenic origin is that of the reported formation of dolomite in the urinary bladder of a Dalmatian dog, possibly as the result of an illness or infection
Although dolomite does not form on the surface of the earth at the present time, massive layers of dolomite can be found in ancient rocks.
Dolomite is one of the few sedimentary rocks that undergoes a significant mineralogical change after it is deposited.
Dolomite rocks are originally deposited as calcite/aragonite-rich limestone, but during a process called diagenesis, the calcite and/or aragonite is transformed into dolomite.
Magnesium-rich ground water containing a significant amount of salt is thought to be essential to dolomite formation.
Thus, warm, tropical marine environments are considered the best sources of dolomite formation.
Dolomite is composed of 52.06% oxygen, 13.03% carbon, 13.18% magnesium, and 21.73% calcium.
Iron and manganese carbonates, barium, and lead are sometimes present as impurities.
As limestone and dolomite shares the same depositional environment as shallow marine, warm water where organism can accumulate which in turn when deposits form carbonate.
So in formation of dolomite it is thought to be the alteration of carbonate by magnesium rich water, Magnesium in the water converts calcite into dolomite, This alteration is the chemical change in the limestone which is called dolomitization.
This can turn limestone into complete dolomite or can be partial alteration of the rock and is dolomitic limestone.
Modern dolomite formation has been found to occur under anaerobic conditions in supersaturated saline lagoons along the Rio de Janeiro coast of Brazil, namely, Lagoa Vermelha and Brejo do Espinho.
Dolomite is often thought that dolomite will develop only with the help of sulphate-reducing bacteria (e.g. Desulfovibrio brasiliensis).
However, low-temperature dolomite may occur in natural environments rich in organic matter and microbial cell surfaces.
This occurs as a result of magnesium complexation by carboxyl groups associated with organic matter.
Vast deposits of dolomite are present in the geological record, but the mineral is relatively rare in modern environments.
Reproducible, inorganic low-temperature syntheses of dolomite and magnesite were published for the first time in 1999.
Those laboratory experiments showed how the initial precipitation of a metastable "precursor" (such as magnesium calcite) will change gradually into more and more of the stable phase (such as dolomite or magnesite) during periodical intervals of dissolution and re-precipitation.
The general principle governing the course of this irreversible geochemical reaction has been coined "breaking Ostwald's step rule".
There is some evidence for a biogenic occurrence of dolomite.
One example is that of the formation of dolomite in the urinary bladder of a Dalmatian dog, possibly as the result of an illness or infection.
The physical properties of dolomite that are useful for identification are presented in the table on this page. Dolomite has three directions of perfect cleavage.
This may not be evident when the dolomite is fine-grained. However, when it is coarsely crystalline the cleavage angles can easily be observed with a hand lens.
Dolomite has a Mohs hardness of 3 1/2 to 4 and is sometimes found in rhombohedral crystals with curved faces.
Dolomite produces a very weak reaction to cold, dilute hydrochloric acid; however, if the acid is warm or if the dolomite is powdered, a much stronger acid reaction will be observed.
(Powdered dolomite can easily be produced by scratching it on a streak plate.)
Dolomite is very similar to the mineral calcite. Calcite is composed of calcium carbonate (CaCO3), while dolomite is a calcium magnesium carbonate (CaMg(CO3)2).
These two minerals are one of the most common pairs to present a mineral identification challenge in the field or classroom.
The best way to tell these minerals apart is to consider their hardness and acid reaction.
Calcite has a hardness of 3, while dolomite is slightly harder at 3 1/2 to 4. Calcite is also strongly reactive with cold hydrochloric acid, while dolomite will effervesce weakly with cold hydrochloric acid.
The chemical formula of Dolomite, which is a calcium double carbonate, is CaMg(CO3)2, it was first determined by the French geologist Deodat de Dolomieu that dolomite is a mineral separate from calcite, and it was named by Count Dolomien in 1791.
CaCO3 : 54.35%
CaO: 30.4%
MgCO3: 45.65%
MgO: 21.7%
CO2 : 47.9%
Dolomite is formed by the inclusion of CaO or the taking of MgO from limestones.
Therefore, it is in between with the childhood stones and is always transitional with limestones laterally and vertically.
Dolomite has been designed in a way that can be designed according to the calcite application in the body.
Theoretical % CaCO3 + 10% and CaCO3 excess
Calcite Dolomite
MgCO3 5-10% Magnesium Limestone
MgCO3< 5% Limestone
Commercially, dolomite can be applied at various temperatures.
Uncalcined dolomite is called "raw dolomite", dolomite heat-treated at 1100 oC "calcined dolomite", and "sintered dolomite" between 1650 oC and 2100 oC.
In principle, limestone and dolomite, which are carbonate rocks, are the most important rocks used in industry.
Limestone is a sedimentary rock containing CaCO3.
Dolomite, on the other hand, are rocks containing CaCO3 and MgCO3.
Aragonite (CaCO3) is not comparable in terms of the quality you should have in the same space.
Aragonite is an observable mineral as calcite changes over time.
Other carbonate minerals are siderite (FeCO3), ankerite (Ca2MgFe(CO3)) and magnesite (MgCO3).
Magnesite and developing co-stone and dolomite occur in small amounts in the whole.
Similar conveniences, it is not often possible to distinguish carbonate minerals from one another.
Dolomites specific taste, crystalline formula and other beneficial properties become your rock.
The rate of acceleration of minerals in the diluted hydrochloric acid method is known as a method for their promotion in such minerals.
Calcite is much more soluble in diluted HCl solution than dolomite.
Thus, if this method is tried on a fresh surface, various reliefs will be seen when looking at the surface where the dolomite is found with a hand lens.
Another technique is the dyeing technique, which is actually based on the principle of decreasing dissolution difference in the direction of aragonite-calcite and dolomite.
However, this method is very difficult to use in the field, it is generally used in a laboratory environment.
X-Ray diffractometry techniques are mainly used to determine the carbonate mineralogy of large sized samples in the laboratory environment.
In this method, the calcite dolomite ratio in the rock or the percentage values of these minerals can be found by comparing them with a known standard.
Thin section analysis using a binocular microscope also helps to identify these carbonate rocks.
Dolomite is very difficult to identify calcite, dolomite and ankerite in thin sections without staining.
During these definitions, the type, texture and structure of carbonate particles are investigated.
One of the most important elements used in definitions is fossils and fossil traces.
As a filler in road construction and concrete construction.
In agriculture, as a filler in fertilizer production and in soil improvement.
In production in the glass and soda industry.
As a filler in the paint industry.
in the ceramic industry.
As a bleach in the chemical industry.
In the filtration of water.
In the production of Metallic Magnesium
In the production of MgO from seawater and underground Magnesium salts.
In the production of refractory bricks and mortars.
In the iron and steel industry, in the sintering of iron ore, as a slag maker in steel production and as a protector of refractory bricks.
Dolomite is used as an ornamental stone, a concrete aggregate, and a source of magnesium oxide, as well as in the Pidgeon process for the production of magnesium.
Dolomite is an important petroleum reservoir rock, and serves as the host rock for large strata-bound Mississippi Valley-Type (MVT) ore deposits of base metals such as lead, zinc, and copper.
Where calcite limestone is uncommon or too costly, dolomite is sometimes used in its place as a flux for the smelting of iron and steel.
Large quantities of processed dolomite are used in the production of float glass.
In horticulture, dolomite and dolomitic limestone are added to soils and soilless potting mixes as a pH buffer and as a magnesium source.
Dolomite is also used as the substrate in marine (saltwater) aquariums to help buffer changes in the pH of the water.
Calcined dolomite is also used as a catalyst for destruction of tar in the gasification of biomass at high temperature.
Particle physics researchers like to build particle detectors under layers of dolomite to enable the detectors to detect the highest possible number of exotic particles.
Because dolomite contains relatively minor quantities of radioactive materials, it can insulate against interference from cosmic rays without adding to background radiation levels.
In addition to being an industrial mineral, dolomite is highly valued by collectors and museums when it forms large, transparent crystals.
The specimens that appear in the magnesite quarry exploited in Eugui, Esteribar, Navarra (Spain) are considered among the best in the world
antacids (neutralizes stomach acid)
base for face creams, baby powders, or toothpaste
calcium/magnesium nutritional supplements for animals and humans
ceramic glazes on china and other dinnerware (dolomite is used as source of magnesia and calcia)
fertilizers (dolomite added as soil nutrient)
glass (used for high refractive optical glass)
gypsum impressions from which dental plates are made (magnesium carbonate)
mortar and cement
plastics, rubbers, and adhesives
Although calcium carbonate (the kind found in dolomite) has the highest concentration of calcium by weight (40%) and is the most common preparation available, this form of calcium is relatively insoluble and can be difficult to break down in the body.
In contrast, calcium citrate, although containing about half as much calcium by weight (21%), is a more soluble form.
Since calcium citrate does not require gastric acid for absorption, it is considered a better source of supplemental calcium, particularly for the elderly, whose stomach acid secretions are decreased.
Dolomite and limestone have similar uses as used in the construction purposes after being crushed into pebbles and cobbles size.
These can also be used into dimension stone after cutting into regular size.
Dolomite is the preference in the construction industry than that of the limestone because of its greater hardness and less chemical reactivity to acids which makes it perfect for construction uses.
Dolomitization is a process where limestone is converted, it provides opportunity for a reservoir in oil and gas industry because of the reduction in size of limestone which leaves pore spaces that are often filled by oil and gas.
These are also host rock for lead, zinc and copper deposits.
Other uses of dolomite are in the chemical industry used to extract magnesia where it is served as the source rock.
Steel industry use it in processing iron ore and is also used in the agriculture industry as a feed additive for live stock aiding in the egg shells which are made of calcium.
Dolomiteis also used in the production of glass and ceramics.
Dolomite is chosen for many construction and building product applications due to its hardness and density.
A few applications applications are:
Asphalt and concrete mixes in a wide variety of construction applications such as highways, airport runways, parking lots, sidewalks, curbs, and residential streets and roadways, just to name a few.
Glass and ceramics manufacture.
As a sintering agent in iron ore pelletization
As a flux agent in steel making.
For pH control of soil by farmers.
Production of magnesium salts including magnesia, which is used in pharmaceuticals
Dolomite can also serve as an oil and gas reservoir rock.
IUPAC NAME:
calcium magnesium dicarbonate
calcium magnesium(2+) ion dicarbonate
DOLOMITE
Dolomite
dolomite
Dolomitic limestone
MAGNESIUM CALCIUM CARBONATE
SYNONYMS:
Dolomite
230-274-9
7000-29-5
CALCIUM MAGNESIUM CARBONATE
Calcium magnesium carbonate
calcium;magnesium;dicarbonate
Calciummagnesiumcarbonat
Carbonate de calcium et de magnésium
Carbonic acid, calcium magnesium salt (2:1:1)
MFCD03613593