Brucite is the

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

form of

magnesium hydroxide Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (). Magnesium hydroxide is a common component of antacids, such as milk ...

, with the chemical formula Mg( OH)₂. It is a common alteration product of

periclase Periclase is a magnesium mineral that occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. It is a cubic form of magnesium oxide ( Mg O). In nature it usually forms a solid solution with wüstit ...

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...

; a low-temperature

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenat ...

mineral in metamorphosed

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s and chlorite

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...

s; and formed during

serpentinization Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite. Minerals formed by serpentinization include the serpentine group mine ...

dunite Dunite (), also known as olivinite (not to be confused with the mineral olivenite), is an intrusive igneous rock of ultramafic composition and with phaneritic (coarse-grained) texture. The mineral assemblage is greater than 90% olivine, with ...

s. Brucite is often found in association with serpentine, calcite,

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...

, dolomite, magnesite,

hydromagnesite Hydromagnesite is a hydrated magnesium carbonate mineral with the formula Mg5(CO3)4(OH)2·4H2O. It generally occurs associated with the weathering products of magnesium containing minerals such as serpentine or brucite. It occurs as incrustations ...

artinite Artinite is a hydrated magnesium carbonate mineral with formula: Mg2(CO3)(OH)2·3H2O. It forms white silky monoclinic prismatic crystals that are often in radial arrays or encrustations. It has a Mohs hardness of 2.5 and a specific gravity of 2. ...

talc Talc, or talcum, is a clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent a ...

and

chrysotile Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R.&nb ...

. It adopts a layered CdI₂-like structure with hydrogen-bonds between the layers.

Discovery

Brucite was first described in 1824 by François Sulpice Beudant and named for the discoverer, American mineralogist,

Archibald Bruce Archibald Bruce may refer to: * Archibald Bruce (writer), Scottish theological writer * Archibald Bruce (mineralogist) Archibald Bruce (February 1777 – February 22, 1818) was an American physician and mineralogist. Biography Bruce was bor ...

(1777–1818). A fibrous variety of brucite is called nemalite. It occurs in fibers or laths, usually elongated along

010 010 may refer to: * 10 (number) * 8 (number) in octal numeral notation * Motorola 68010, a microprocessor released by Motorola in 1982 * 010, the telephone area code of Beijing * 010, the Rotterdam Rotterdam ( , , , lit. ''The Dam on the R ...

but sometimes

120 120 may refer to: *120 (number), the number * AD 120, a year in the 2nd century AD *120 BC, a year in the 2nd century BC *120 film, a film format for still photography * ''120'' (film), a 2008 film * 120 (MBTA bus) * 120 (New Jersey bus) * 120 (Ken ...

crystalline directions.

Occurrence

A notable location in the U.S. is Wood's Chrome Mine, Cedar Hill Quarry, Lancaster County, Pennsylvania. Yellow, white and blue Brucite with a botryoidal habit was discovered in Qila Saifullah District of Province Baluchistan, Pakistan. And then in a later discovery Brucite also occurred in the Bela

Ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found ...

of Wadh, Khuzdar District, Province Baluchistan, Pakistan. Brucite has also occurred from South Africa, Italy, Russia, Canada, and other localities as well but the most notable discoveries are the US, Russian and Pakistani examples.

Industrial applications

Synthetic brucite is mainly consumed as a precursor to magnesia (MgO), a useful refractory insulator. It finds some use as a

flame retardant The term flame retardants subsumes a diverse group of chemicals that are added to manufactured materials, such as plastics and textiles, and surface finishes and coatings. Flame retardants are activated by the presence of an ignition source and ...

because it thermally decomposes to release water in a similar way to

aluminium hydroxide Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic an ...

and mixtures of huntite and

. It also constitutes a significant source of magnesium for industry. Although generally deemed safe, brucite can be contaminated with naturally occurring asbestos fibers.

Magnesium attack of cement and concrete

When

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

are exposed to Mg²⁺, the neoformation of brucite, an expansive material, may induce

mechanical stress In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elonga ...

in the hardened cement paste or may clog the porous system creating a buffering effect and delaying deterioration of the CSH phase into MSH phase. The exact magnitude of impact that brucite has over cement paste is still debatable. Prolonged contact between sea water or brines and concrete may induce durability issue although high concentrations are required for this effect, which are rare to find in nature. The use of dolomite as aggregate in concrete can also cause magnesium attack and should be avoided.

Gallery

Brucite - Killa Saifullah, Pakistan.jpg, Yellow brucite from Balochistan, Pakistan Nemalite.jpg, Nemalite Brucite-169935.jpg, Brucite crystals from the Sverdlovsk Region, Urals, Russia (size: 10.5 x 7.8 x 7.4 cm) Mg(OH)2Xray.jpg, Structure of Mg(OH)₂

Discovery

Occurrence

Industrial applications

Magnesium attack of cement and concrete

Gallery

See also

References

Further reading