関: calcite、calcium carbonate、limestone、marble、vaterite

WordNet

a mineral form of crystalline calcium carbonate; dimorphic with calcite
paint or stain like marble; "marble paper"
a hard crystalline metamorphic rock that takes a high polish; used for sculpture and as building material
a sculpture carved from marble
a small ball of glass that is used in various games
a common mineral consisting of crystallized calcium carbonate; a major constituent of limestone
a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals
a colorless or pale brown mica with sodium

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〈U〉『大理石』 / 《複数形で;単数扱い》おはじき遊戯 / 〈C〉おはじきの石 / 大理石[製]の;大理石模様の / (大理石のように)硬い,冷たい;滑らかな;白い
方解石(炭酸カルシウムの結晶で石灰岩・大理石・チョークの主成分)
石灰石

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/07/20 22:52:14」(JST)

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Aragonite is a carbonate mineral, one of the two most common, naturally occurring, crystal forms of calcium carbonate, CaCO₃ (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including precipitation from marine and freshwater environments.

Aragonite's crystal lattice differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching stalactitic forms called flos-ferri ("flowers of iron") from their association with the ores at the Carinthian iron mines.

Occurrence

The type location for aragonite is Molina de Aragón (Guadalajara, Spain), 25 km from Aragon for which it was named in 1797.^[1] An aragonite cave, the Ochtinská Aragonite Cave, is situated in Slovakia. In the US, aragonite in the form of stalactites and "cave flowers" (anthodite) is known from Carlsbad Caverns and other caves. Massive deposits of oolitic aragonite sand are found on the seabed in the Bahamas.

Aragonite is the high pressure polymorph of calcium carbonate. As such, it occurs in high pressure metamorphic rocks such as those formed at subduction zones.

Aragonite forms naturally in almost all mollusk shells, and as the calcareous endoskeleton of warm- and cold-water corals (Scleractinia). Several serpulids have aragonitic tubes. Because the mineral deposition in mollusk shells is strongly biologically controlled, some crystal forms are distinctively different from those of inorganic aragonite. In some mollusks, the entire shell is aragonite; in others, aragonite forms only discrete parts of a bimineralic shell (aragonite plus calcite). The nacreous layer of the aragonite fossil shells of some extinct ammonites forms an iridescent material called ammolite.

Aragonite also forms in the ocean and in caves as inorganic precipitates called marine cements and speleothems, respectively. Aragonite is not uncommon in serpentinites where high Mg in pore solutions apparently inhibits calcite growth and promotes aragonite precipitation.

Aragonite is metastable at the low pressures near the Earth's surface and is thus commonly replaced by calcite in fossils. Aragonite older than the Carboniferous is essentially unknown.^[4] It can also be synthesized by adding a calcium chloride solution to a sodium carbonate solution at temperatures above 60 °C (140 °F) or in water-ethanol mixtures at ambient temperatures.^[5]

Physical properties

Aragonite is thermodynamically unstable at standard temperature and pressure, and tends to alter to calcite on scales of 10⁷ to 10⁸ years. The mineral vaterite, also known as μ-CaCO₃, is another phase of calcium carbonate that is metastable at ambient conditions typical of Earth's surface, and decomposes even more readily than aragonite.^{[citation needed]}

Uses

In aquaria, aragonite is considered essential for the replication of reef conditions. Aragonite provides the materials necessary for much sea life and also keeps the pH of the water close to its natural level, to prevent the dissolution of biogenic calcium carbonate.^[6]

Aragonite has been successfully tested for the removal of pollutants like zinc, cobalt and lead from contaminated wastewaters.^[7]

Gallery

Aragonite crystals from Cuenca, Castile-La Mancha, Spain
Cluster of twinned aragonite from Morocco
Remnant biogenic aragonite (thin, rainbow-colored shell) on the ammonite Baculites (Pierre Shale, Late Cretaceous, South Dakota).
Scanning electron microscope image of aragonite layers in the nacre of a blue mussel (Mytilus edulis).
Pink Aragonite Crystals
Fluorescence of Aragonite

References

^ ^a ^b Mindat.org
^ Handbook of Mineralogy
^ Webmineral data
^ Runnegar, B. (1987). "Shell microstructures of Cambrian molluscs replicated by phosphate". Alcheringa: an Australasian Journal of Palaeontology. 9 (4): 245–257. doi:10.1080/03115518508618971.
^ Sand, K.K., Rodriguez-Blanco, J.D., Makovicky, E., Benning, L.G. and Stipp, S. (2012) Crystallization of CaCO3 in water-ethanol mixtures: spherulitic growth, polymorph stabilization and morphology change. Crystal Growth and Design, 12, 842-853. doi:10.1021/cg2012342.
^ Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC, Feely RA, Gnanadesikan A, Gruber N, Ishida A, Joos F, Key RM, Lindsay K, Maier-Reimer E, Matear R, Monfray P, Mouchet A, Najjar RG, Plattner G-K, Rodgers KB, Sabine CL, Sarmiento JL, Schlitzer R, Slater RD, Totterdell IJ, Weirig M-F, Yamanaka Y, Yool A (2005) Anthropogenic ocean acidification over the 21st century and its impact on calcifying organisms. Nature 437: 681-686
^ Köhler, S., Cubillas, P., Rodríguez-Blanco, J.D., Prieto, M. (2007) Removal of cadmium from wastewaters by aragonite shells and the influence of other divalent cations. Environmental Science and Technology, 41, 112-118. doi:10.1021/es060756j

External links

The Ochtinska aragonite cave
Kosovo Caves Aragonite Formations

English Journal

Biochemical characterization of the native α-carbonic anhydrase purified from the mantle of the Mediterranean mussel, Mytilus galloprovincialis.

Perfetto R1, Del Prete S1,2, Vullo D2, Sansone G3, Barone C4, Rossi M1, Supuran CT2, Capasso C1.
Journal of enzyme inhibition and medicinal chemistry.J Enzyme Inhib Med Chem.2017 Dec;32(1):632-639. doi: 10.1080/14756366.2017.1284069.
A α-carbonic anhydrase (CA, EC 4.2.1.1) has been purified and characterized biochemically from the mollusk Mytilus galloprovincialis. As in most mollusks, this α-CA is involved in the biomineralization processes leading to the precipitation of calcium carbonate in the mussel shell. The new enzyme
PMID 28229634

Ciprofloxacin HCl-loaded calcium carbonate nanoparticles: preparation, solid state characterization, and evaluation of antimicrobial effect against Staphylococcus aureus.

Maleki Dizaj S1,2, Lotfipour F3,4, Barzegar-Jalali M4, Zarrintan MH4, Adibkia K4.
Artificial cells, nanomedicine, and biotechnology.Artif Cells Nanomed Biotechnol.2017 May;45(3):535-543. doi: 10.3109/21691401.2016.1161637. Epub 2016 Mar 25.
Ciprofloxacin HCl-loaded calcium carbonate (CaCO3) nanoparticles were prepared via a w/o microemulsion method and characterized by dynamic light scattering, scanning electron microscopy, X-ray powder diffraction (XRPD) analysis, differential scanning calorimetry (DSC), and Fourier transform infrared
PMID 27012878

Addition of calcium compounds to reduce soluble oxalate in a high oxalate food system.

Bong WC1, Vanhanen LP1, Savage GP2.
Food chemistry.Food Chem.2017 Apr 15;221:54-57. doi: 10.1016/j.foodchem.2016.10.031. Epub 2016 Oct 8.
Spinach (Spinacia oleracea L.) is often used as a base vegetable to make green juices that are promoted as healthy dietary alternatives. Spinach is known to contain significant amounts of oxalates, which are toxic and, if consumed regularly, can lead to the development of kidney stones. This researc
PMID 27979238

Japanese Journal

SYNTHESIS OF CALCITE AND ARAGONITE, AND QUANTITATIVE EVALUATION OF AMINO ACID ADSORPTION ON THEIR SURFACES

KAWANO MOTOHARU,TOKONAMI MISAKI
Clay science 18(2), 33-41, 2014-06
NAID 40020249027

EFFECT OF ORGANIC ACIDS ON THE PRECIPITATION RATE AND POLYMORPHISM OF CALCIUM CARBONATE MINERALS IN SOLUTIONS WITH MG²⁺ IONS

KAWANO MOTOHARU,TOKONAMI MISAKI
Clay science 18(1), 1-10, 2014-03
NAID 40020094334

EFFECT OF ORGANIC ACIDS ON THE PRECIPITATION RATE AND POLYMORPHISM OF CALCIUM CARBONATE MINERALS IN SOLUTIONS WITH Mg^<2+> IONS

KAWANO MOTOHARU,TOKONAMI MISAKI
Clay science 18(1), 1-10, 2014-03
… In addition, adsorption experiments with these organic acids were conducted on the surfaces of calcite and aragonite to reveal the adsorption affinity of organic acids for CaCO_3 minerals. … Adsorption experiments revealed that adsorption affinity of organic acids was much higher for the surface of aragonite than that for the calcite surface, and showed adsorption amounts in the following order: citric acid > …
NAID 110009818041

Related Pictures

Aragonite image - Free stock photo - Public Domain photo - CC0 Images Capricorn Healing Stone - Aragonite | Zodiac Signs Aragonite - Wikipedia Aragonite | Gemstone Buzz Aragonite - Soulful Crystals aragonite | mineral | Britannica.com 1.9 Aragonite crystals clusters Aragonite crystal specimens Morocco Aragonite crystals

★リンクテーブル★

リンク元	「vaterite」「marble」「霰石」「calcite」「limestone」

「vaterite」

Aragonite
	Aragonite from Salsigne mine, Salsigne, Aude, France - Size: 30x30x20 cm
General
Category	Carbonate mineral
Formula; (repeating unit)	CaCO3
Strunz classification	5.AB.15
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm); H-M symbol: (2/m 2/m 2/m)
Space group	Pmcn
Unit cell	a = 4.95, b = 7.96; c = 5.74 [Å]; Z = 4
Identification
Color	White, red, yellow, orange, green, purple, grey, blue and brown
Crystal habit	Pseudohexagonal, prismatic crystals, acicular, columnar, globular, reniform, pisolitic, coralloidal, stalactitic, internally banded
Twinning	Polysynthetic parallel to {100} cyclically on {110}
Cleavage	Distinct on {010}, imperfect {110} and {011}
Fracture	Subconchoidal
Tenacity	Brittle
Mohs scale hardness	3.5-4
Luster	Vitreous, resinous on fracture surfaces
Streak	White
Diaphaneity	Translucent to transparent
Specific gravity	2.95
Optical properties	Biaxial (-)
Refractive index	nα = 1.529 - 1.530 nβ = 1.680 - 1.682 nγ = 1.685 - 1.686
Birefringence	δ = 0.156
2V angle	18°
Solubility	Dilute acid
Other characteristics	Fluorescence: pale rose, yellow, white or bluish; phosphorescence: greenish or white (LW UV); yellowish (SW UV)
References