Calcite

Last updated
Calcite
Calcite-20188.jpg
General
Category Carbonate minerals
Formula
(repeating unit)
CaCO3
Strunz classification 5.AB.05
Crystal system Trigonal
Crystal class Hexagonal scalenohedral (3m)
H-M symbol: (3 2/m)
Space group R3c
Unit cell a = 4.9896(2)  Å,
c = 17.0610(11) Å; Z = 6
Identification
ColorTypically colorless or white - may have shades of various colors
Crystal habit Crystalline, granular, stalactitic, concretionary, massive, rhombohedral
Twinning Common by four twin laws
Cleavage Perfect on {1011} three directions with angle of 74° 55' [1]
Fracture Conchoidal
Tenacity Brittle
Mohs scale hardness3 (defining mineral)
Luster Vitreous to pearly on cleavage surfaces
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.71
Optical propertiesUniaxial (−)
Refractive index nω = 1.640–1.660
nε = 1.486
Birefringence δ = 0.154–0.174
Solubility Soluble in dilute acids
Other characteristicsMay fluoresce red, blue, yellow, and other colors under either SW and LW UV; phosphorescent
References [2] [3] [4]
Crystal structure of calcite Calcite.png
Crystal structure of calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 3 as "calcite".

Contents

Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, [5] [6] and vaterite is even less stable.

Etymology

Calcite is derived from the German Calcit, a term from the 19th century that came from the Latin word for lime, calx (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. [7]

When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is reserved for a variety of gypsum; but also for a similar-looking, translucent variety of fine-grained banded deposit of calcite. [8]

Unit cell and Miller indices

In publications, two different sets of Miller indices are used to describe directions in calcite crystals - the hexagonal system with three indices h, k, l and the rhombohedral system with four indices h, k, l, i. To add to the complications, there are also two definitions of unit cell for calcite. One, an older "morphological" unit cell, was inferred by measuring angles between faces of crystals and looking for the smallest numbers that fit. Later, a "structural" unit cell was determined using X-ray crystallography. The morphological unit cell has approximate dimensions a = 10 Å and c = 8.5 Å , while for the structural unit cell they are a = 5 Å and c = 17 Å . For the same orientation, c must be multiplied by 4 to convert from morphological to structural units. As an example, the cleavage is given as "perfect on {1 0 1 1}" in morphological coordinates and "perfect on {1 0 1 4}" in structural units. (In hexagonal indices, these are {1 0 1} and {1 0 4}.) Twinning, cleavage and crystal forms are always given in morphological units. [3] [9]

Properties

Form

Over 800 forms of calcite crystals have been identified. Most common are scalenohedra, with faces in the hexagonal {2 1 1} directions (morphological unit cell) or {2 1 4} directions (structural unit cell); and rhombohedral, with faces in the {1 0 1} or {1 0 4} directions (the most common cleavage plane). [9] Habits include acute to obtuse rhombohedra, tabular forms, prisms, or various scalenohedra. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. A fibrous, efflorescent form is known as lublinite. [10] Cleavage is usually in three directions parallel to the rhombohedron form. Its fracture is conchoidal, but difficult to obtain.

Scalenohedral faces are chiral and come in pairs with mirror-image symmetry; their growth can be influenced by interaction with chiral biomolecules such as L- and D-amino acids. Rhombohedral faces are achiral. [9]

Hardness

Calcite has a defining Mohs hardness of 3, a specific gravity of 2.71, and its luster is vitreous in crystallized varieties. Color is white or none, though shades of gray, red, orange, yellow, green, blue, violet, brown, or even black can occur when the mineral is charged with impurities.

Optical

Calcite-refraction-property.jpg
Calcite-refraction-property.jpg
Photograph of calcite displaying the characteristic birefringence optical behaviour.

Calcite is transparent to opaque and may occasionally show phosphorescence or fluorescence. A transparent variety called Iceland spar is used for optical purposes. Acute scalenohedral crystals are sometimes referred to as "dogtooth spar" while the rhombohedral form is sometimes referred to as "nailhead spar".

Demonstration of birefringence in calcite, using 445 nm laser Fluorescence in calcite.jpg
Demonstration of birefringence in calcite, using 445 nm laser

Single calcite crystals display an optical property called birefringence (double refraction). This strong birefringence causes objects viewed through a clear piece of calcite to appear doubled. The birefringent effect (using calcite) was first described by the Danish scientist Rasmus Bartholin in 1669. At a wavelength of ≈590 nm calcite has ordinary and extraordinary refractive indices of 1.658 and 1.486, respectively. [11] Between 190 and 1700 nm, the ordinary refractive index varies roughly between 1.9 and 1.5, while the extraordinary refractive index varies between 1.6 and 1.4. [12]

Chemical

Calcite, like most carbonates, will dissolve in acids via the reaction

CaCO
3
(s) + 2H+
(aq) → Ca2+(aq) + H
2
O + CO
2
(g)

The carbon dioxide released by this reaction produces a characteristic effervescence when dilute hydrochloric acid dropped on a calcite sample.

Ambient carbon dioxide, due to its acidity, has a slight solubilizing effect on calcite. The overall reaction is

CaCO
3
(s) + H
2
O + CO
2
(aq) → Ca2+(aq) + 2HCO
3
(aq)

If the amount of dissolved carbon dioxide drops, the reaction reverses to precipitate calcite. As a result, calcite can be either dissolved by groundwater or precipitated by groundwater, depending on such factors as the water temperature, pH, and dissolved ion concentrations. When conditions are right for precipitation, calcite forms mineral coatings that cement rock grains together and can fill fractures. When conditions are right for dissolution, the removal of calcite can dramatically increase the porosity and permeability of the rock, and if it continues for a long period of time, may result in the formation of caves. Continued dissolution of calcium carbonate-rich formations can lead to the expansion and eventual collapse of cave systems, resulting in various forms of karst topography. [13]

Calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. Calcite is also more soluble at higher pressures. [14]

Pure calcite has the composition CaCO
3
. However, the calcite in limestone often contains a few percent of magnesium. Calcite in limestone is divided into low-magnesium and high-magnesium calcite, with the dividing line placed at a composition of 4% magnesium. High-magnesium calcite retains the calcite mineral structure, which is distinct from that of dolomite, MgCa(CO
3
)
2
. [15] Calcite can also contain small quantities of iron and manganese. [16] Manganese may be responsible for the fluorescence of impure calcite, as may traces of organic compounds. [17]

Use and applications

One of several calcite or alabaster perfume jars from the tomb of Tutankhamun, d. 1323 BC Tutankhamun's Alabaster Jar.jpg
One of several calcite or alabaster perfume jars from the tomb of Tutankhamun, d. 1323 BC

Ancient Egyptians carved many items out of calcite, relating it to their goddess Bast, whose name contributed to the term alabaster because of the close association. Many other cultures have used the material for similar carved objects and applications. [18]

A transparent variety of calcite known as Iceland spar may have been used by Vikings for navigating on cloudy days. [19]

High-grade optical calcite was used in World War II for gun sights, specifically in bomb sights and anti-aircraft weaponry. [20] Also, experiments have been conducted to use calcite for a cloak of invisibility. [21]

Microbiologically precipitated calcite has a wide range of applications, such as soil remediation, soil stabilization and concrete repair.

Calcite, obtained from an 80 kg sample of Carrara marble, [22] is used as the IAEA-603 isotopic standard in mass spectrometry for the calibration of δ18O and δ13C. [23]

Natural occurrence

Calcite is a common constituent of sedimentary rocks, limestone in particular, much of which is formed from the shells of dead marine organisms. Approximately 10% of sedimentary rock is limestone. It is the primary mineral in metamorphic marble. It also occurs in deposits from hot springs as a vein mineral; in caverns as stalactites and stalagmites; and in volcanic or mantle-derived rocks such as carbonatites, kimberlites, or rarely in peridotites.

Calcite is often the primary constituent of the shells of marine organisms, e.g., plankton (such as coccoliths and planktic foraminifera), the hard parts of red algae, some sponges, brachiopods, echinoderms, some serpulids, most bryozoa, and parts of the shells of some bivalves (such as oysters and rudists). Calcite is found in spectacular form in the Snowy River Cave of New Mexico as mentioned above, where microorganisms are credited with natural formations. Trilobites, which became extinct a quarter billion years ago, had unique compound eyes that used clear calcite crystals to form the lenses. [24]

The largest documented single crystal of calcite originated from Iceland, measured 7×7×2 m and 6×6×3 m and weighed about 250 tons. [25]

Bedding parallel veins of fibrous calcite, often referred to in quarrying parlance as "beef", occur in dark organic rich mudstones and shales, these veins are formed by increasing fluid pressure during diagenesis. [26]

Formation processes

Calcite formation can proceed by several pathways, from the classical terrace ledge kink model [27] to the crystallization of poorly ordered precursor phases (amorphous calcium carbonate, ACC) via an Ostwald ripening process, or via the agglomeration of nanocrystals. [28]

The crystallization of ACC can occur in two stages: first, the ACC nanoparticles rapidly dehydrate and crystallize to form individual particles of vaterite. Secondly, the vaterite transforms to calcite via a dissolution and reprecipitation mechanism with the reaction rate controlled by the surface area of calcite. [29] The second stage of the reaction is approximately 10 times slower. However, the crystallization of calcite has been observed to be dependent on the starting pH and presence of Mg in solution. [30] A neutral starting pH during mixing promotes the direct transformation of ACC into calcite. Conversely, when ACC forms in a solution that starts with a basic initial pH, the transformation to calcite occurs via metastable vaterite, which forms via a spherulitic growth mechanism. [31] In a second stage this vaterite transforms to calcite via a surface-controlled dissolution and recrystallization mechanism. Mg has a noteworthy effect on both the stability of ACC and its transformation to crystalline CaCO3, resulting in the formation of calcite directly from ACC, as this ion destabilizes the structure of vaterite.

Calcite may form in the subsurface in response to activity of microorganisms, such as during sulfate-dependent anaerobic oxidation of methane, where methane is oxidized and sulfate is reduced by a consortium of methane oxidizers and sulfate reducers, leading to precipitation of calcite and pyrite from the produced bicarbonate and sulfide. These processes can be traced by the specific carbon isotope composition of the calcites, which are extremely depleted in the 13C isotope, by as much as −125 per mil PDB13C). [32]

In Earth history

Calcite seas existed in Earth history when the primary inorganic precipitate of calcium carbonate in marine waters was low-magnesium calcite (lmc), as opposed to the aragonite and high-magnesium calcite (hmc) precipitated today. Calcite seas alternated with aragonite seas over the Phanerozoic, being most prominent in the Ordovician and Jurassic. Lineages evolved to use whichever morph of calcium carbonate was favourable in the ocean at the time they became mineralised, and retained this mineralogy for the remainder of their evolutionary history. [33] Petrographic evidence for these calcite sea conditions consists of calcitic ooids, lmc cements, hardgrounds, and rapid early seafloor aragonite dissolution. [34] The evolution of marine organisms with calcium carbonate shells may have been affected by the calcite and aragonite sea cycle. [35]

Calcite is one of the minerals that has been shown to catalyze an important biological reaction, the formose reaction, and may have had a role in the origin of life. [9] Interaction of its chiral surfaces (see Form) with aspartic acid molecules results in a slight bias in chirality; this is one possible mechanism for the origin of homochirality in living cells. [36]

See also

Related Research Articles

Limestone Sedimentary rocks made of calcium carbonate

Limestone is a common type of carbonate sedimentary rock. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes have likely been more important for the last 540 million years. Limestone often contains fossils, and these provide scientists with information on ancient environments and on the evolution of life.

Calcium carbonate Chemical compound

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite) and is the main component of eggshells, snail shells, seashells and pearls. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues; as well it was noted that "many calcium supplement formulations contain [the chemical element] Lead and thereby may pose an easily avoidable public health concern," especially in those supplements which were not derived from natural oyster shells.

Dolomite (mineral) Carbonate mineral - CaMg(CO₃)₂

Dolomite 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.

Aragonite Calcium carbonate polymorph

Aragonite is a carbonate mineral, one of the three 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.

Speleothem Structure formed in a cave by the deposition of minerals from water

A speleothem is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies.

Ooid Small sedimentary grain that forms on shallow tropical seabeds

Ooids are small, spheroidal, "coated" (layered) sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals. Ooids usually form on the sea floor, most commonly in shallow tropical seas. After being buried under additional sediment, these ooid grains can be cemented together to form a sedimentary rock called an oolite. Oolites usually consist of calcium carbonate; these belong to the limestone rock family. Pisoids are similar to ooids, but are larger than 2 mm in diameter, often considerably larger, as with the pisoids in the hot springs at Carlsbad in the Czech Republic.

Dolomite (rock) Sedimentary carbonate rock that contains a high percentage of the mineral dolomite

Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. In old USGS publications, it was referred to as magnesian limestone, a term now reserved for magnesium-deficient dolomites or magnesium-rich limestones. Dolomite has a stoichiometric ratio of nearly equal amounts of magnesium and calcium. Most dolomite rock formed as a magnesium replacement of limestone or lime mud before lithification. Dolomite rock is resistant to erosion and can either contain bedded layers or be unbedded. It is less soluble than limestone in weakly acidic groundwater, but it can still develop solution features (karst) over time. Dolomite rock can act as an oil and natural gas reservoir.

Vaterite

Vaterite is a mineral, a polymorph of calcium carbonate (CaCO3). It was named after the German mineralogist Heinrich Vater. It is also known as mu-calcium carbonate (μ-CaCO3) and has a JCPDS number of 13-192. Vaterite belongs to the hexagonal crystal system, whereas calcite is trigonal and aragonite is orthorhombic.

Anthodite

Anthodites (Greek ἄνθος ánthos, "flower", -ode, adjectival combining form, -ite adjectival suffix) are speleothems (cave formations) composed of long needle-like crystals situated in clusters which radiate outward from a common base. The "needles" may be quill-like or feathery. Most anthodites are made of the mineral aragonite (a variety of calcium carbonate, CaCO3), although some are composed of gypsum (CaSO4·2H2O).

Kutnohorite Mineral of calcium manganese carbonate

Kutnohorite is a rare calcium manganese carbonate mineral with magnesium and iron that is a member of the dolomite group. It forms a series with dolomite, and with ankerite. The end member formula is CaMn2+(CO
3
)
2
, but Mg2+ and Fe2+ commonly substitute for Mn2+, with the manganese content varying from 38% to 84%, so the formula Ca(Mn2+,Mg,Fe2+)(CO
3
)
2
better represents the species. It was named by Professor Bukowsky in 1901 after the type locality of Kutná Hora, Bohemia, in the Czech Republic. It was originally spelt "kutnahorite" but "kutnohorite" is the current IMA-approved spelling.

Ikaite

Ikaite is the mineral name for the hexahydrate of calcium carbonate, CaCO3·6H2O. Ikaite tends to form very steep or spiky pyramidal crystals, often radially arranged, of varied sizes from thumbnail size aggregates to gigantic salient spurs. It is only found in a metastable state and decomposes rapidly by losing most of its water content once removed from near-freezing water. This "melting mineral" is more commonly known through its pseudomorphs.

Monohydrocalcite

Monohydrocalcite is a mineral that is a hydrous form of calcium carbonate, CaCO3·H2O. It was formerly also known by the name hydrocalcite, which is now discredited by the IMA. It is a trigonal mineral which is white when pure. Monohydrocalcite is not a common rock-forming mineral, but is frequently associated with other calcium and magnesium carbonate minerals, such as calcite, aragonite, lansfordite, and nesquehonite.

Calcite sea Sea chemistry favouring low-magnesium calcite as the inorganic calcium carbonate precipitate

A calcite sea is a sea in which low-magnesium calcite is the primary inorganic marine calcium carbonate precipitate. An aragonite sea is the alternate seawater chemistry in which aragonite and high-magnesium calcite are the primary inorganic carbonate precipitates. The Early Paleozoic and the Middle to Late Mesozoic oceans were predominantly calcite seas, whereas the Middle Paleozoic through the Early Mesozoic and the Cenozoic are characterized by aragonite seas ).

Aragonite sea Chemical conditions of the sea favouring aragonite deposition

An aragonite sea contains aragonite and high-magnesium calcite as the primary inorganic calcium carbonate precipitates. The chemical conditions of the seawater must be notably high in magnesium content relative to calcium for an aragonite sea to form. This is in contrast to a calcite sea in which seawater low in magnesium content relative to calcium favors the formation of low-magnesium calcite as the primary inorganic marine calcium carbonate precipitate.

Huntite Carbonate mineral

Huntite is a carbonate mineral with the chemical formula Mg3Ca(CO3)4. Huntite crystallizes in the trigonal system and typically occurs as platy crystals and powdery masses. The most common industrial use of huntite is as a natural mixture with hydromagnesite as a flame retardant or fire retardant additive for polymers.

Amorphous calcium carbonate

Amorphous calcium carbonate (ACC) is the amorphous and least stable polymorph of calcium carbonate. ACC is extremely unstable under normal conditions and is found naturally in taxa as wide-ranging as sea urchins, corals, mollusks, and foraminifera. It is usually found as a monohydrate, holding the chemical formula CaCO3·H2O; however, it can also exist in a dehydrated state, CaCO3. ACC has been known to science for over 100 years when a non-diffraction pattern of calcium carbonate was discovered by Sturcke Herman, exhibiting its poorly-ordered nature.

Shell growth in estuaries

Shell growth in estuaries is an aspect of marine biology that has attracted a number of scientific research studies. Many groups of marine organisms produce calcified exoskeletons, commonly known as shells, hard calcium carbonate structures which the organisms rely on for various specialized structural and defensive purposes. The rate at which these shells form is greatly influenced by physical and chemical characteristics of the water in which these organisms live. Estuaries are dynamic habitats which expose their inhabitants to a wide array of rapidly changing physical conditions, exaggerating the differences in physical and chemical properties of the water.

Marine biogenic calcification

Marine biogenic calcification is the process by which marine organisms such as oysters and clams form calcium carbonate. Seawater is full of dissolved compounds, ions and nutrients that organisms can utilize for energy and, in the case of calcification, to build shells and outer structures. Calcifying organisms in the ocean include molluscs, foraminifera, coccolithophores, crustaceans, echinoderms such as sea urchins, and corals. The shells and skeletons produced from calcification have important functions for the physiology and ecology of the organisms that create them.

Patricia Dove American geochemist and crystal growth researcher

Patricia Martin Dove is an American geochemist. She is a University Distinguished Professor and the C.P. Miles Professor of Science at Virginia Tech with appointments in the Department of Geosciences and Department of Chemistry. Her research focuses on the kinetics and thermodynamics of mineral reactions with aqueous solutions in biogeochemical systems. Much of her work is on crystal nucleation and growth during biomineralization and biomaterial synthesis. She was elected a member of the National Academy of Sciences (NAS) in 2012 and currently serves as secretary of Class I, Physical Sciences.

Particulate inorganic carbon

Particulate inorganic carbon (PIC) can be contrasted with dissolved inorganic carbon (DIC), the other form of inorganic carbon found in the ocean. These distinctions are important in chemical oceanography. Particulate inorganic carbon is sometimes called suspended inorganic carbon. In operational terms, it is defined as the inorganic carbon in particulate form that is too large to pass through the filter used to separate dissolved inorganic carbon.

References

  1. Dana, James Dwight; Klein, Cornelis and Hurlbut, Cornelius Searle (1985) Manual of Mineralogy, Wiley, p. 329, ISBN   0-471-80580-7.
  2. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (2003). "Calcite" (PDF). Handbook of Mineralogy. V (Borates, Carbonates, Sulfates). Chantilly, VA, US: Mineralogical Society of America. ISBN   978-0962209741.
  3. 1 2 "Calcite". mindat.org. Retrieved 4 May 2018.
  4. Barthelmy, Dave. "Calcite Mineral Data". webmineral.com. Retrieved 6 May 2018.
  5. Yoshioka S.; Kitano Y. (1985). "Transformation of aragonite to calcite through heating". Geochemical Journal. 19 (4): 24–249. Bibcode:1985GeocJ..19..245Y. doi: 10.2343/geochemj.19.245 .
  6. Staudigel P. T.; Swart P. K. (2016). "Isotopic behavior during the aragonite-calcite transition: Implications for sample preparation and proxy interpretation". Chemical Geology. 442: 130–138. Bibcode:2016ChGeo.442..130S. doi:10.1016/j.chemgeo.2016.09.013.
  7. "calcite (n.)". Online Etymology Dictionary. Retrieved 6 May 2018.
  8. More about alabaster and travertine, brief guide explaining the different use of the same terms by geologists, archaeologists, and the stone trade. Oxford University Museum of Natural History, 2012
  9. 1 2 3 4 Hazen, Robert M. (2004). "Chiral crystal faces of common rock-forming minerals". In Palyi, C.; Zucchi, C.; Caglioti, L. (eds.). Progress in Biological Chirality . Oxford: Elsevier. pp.  137–151.
  10. "Lublinite". mindat.org. Retrieved 6 May 2018.
  11. Elert, Glenn. "Refraction". The Physics Hypertextbook.
  12. Thompson, D. W.; Devries, M. J.; Tiwald, T. E.; Woollam, J. A. (1998). "Determination of optical anisotropy in calcite from ultraviolet to mid-infrared by generalized ellipsometry". Thin Solid Films. 313–314 (1–2): 341–346. Bibcode:1998TSF...313..341T. doi:10.1016/S0040-6090(97)00843-2.
  13. Wolfgang, Dreybrodt (2004). "Dissolution: Carbonate rocks". Encyclopedia of Caves and Karst Science. pp. 295–298. Retrieved 26 December 2020.
  14. Sharp, W. E.; Kennedy, G. C. (March 1965). "The System CaO-CO 2 -H 2 O in the Two-Phase Region Calcite + Aqueous Solution". The Journal of Geology. 73 (2): 391–403. doi:10.1086/627069. S2CID   100971186.
  15. Blatt, Harvey; Middleton, Gerard; Murray, Raymond (1980). Origin of sedimentary rocks (2d ed.). Englewood Cliffs, N.J.: Prentice-Hall. pp. 448–449. ISBN   0136427103.}
  16. Dromgoole, Edward L.; Walter, Lynn M. (February 1990). "Iron and manganese incorporation into calcite: Effects of growth kinetics, temperature and solution chemistry". Chemical Geology. 81 (4): 311–336. Bibcode:1990ChGeo..81..311D. doi:10.1016/0009-2541(90)90053-A.
  17. Pedone, Vicki A.; Cercone, Karen Rose; Burruss, R.C. (October 1990). "Activators of photoluminescence in calcite: evidence from high-resolution, laser-excited luminescence spectroscopy". Chemical Geology. 88 (1–2): 183–190. Bibcode:1990ChGeo..88..183P. doi:10.1016/0009-2541(90)90112-K.
  18. Reed, Kristina (Spring 2017). "Display Case" (PDF). La Sierra Digs (5:2). La Sierra University. Retrieved 6 February 2021.
  19. Perkins, Sid. "Viking seafarers may have navigated with legendary crystals". sciencemag.org. American Association for the Advancement of Science. Retrieved 13 July 2020.
  20. Lister, Priscilla (December 5, 2010). "Borrego's calcite mine trail holds desert wonders". The San Diego Union-Tribune. Retrieved January 8, 2021.
  21. Chen, Xianzhong; Luo, Yu; Zhang, Jingjing; Jiang, Kyle; Pendry, John B.; Zhang, Shuang (2011). "Macroscopic invisibility cloaking of visible light". Nature Communications. 2 (2): 176. arXiv: 1012.2783 . Bibcode:2011NatCo...2E.176C. doi:10.1038/ncomms1176. PMC   3105339 . PMID   21285954.
  22. Department of Nuclear Sciences and Applications, IAEA Environment Laboratories (16 July 2016). "Reference Sheet: Certified Reference Material : IAEA-603 (calcite) – Stable Isotope Reference Material for δ13C and δ18O" (PDF). IAEA. p. 2. Retrieved 28 February 2017.
  23. "IAEA-603 , Calcite". Reference Products for Environment and Trade. International Atomic Energy Agency. Retrieved 27 February 2017.
  24. Angier, Natalie (3 March 2014). "When Trilobites Ruled the World". The New York Times . Retrieved 10 March 2014.
  25. Rickwood, P. C. (1981). "The largest crystals" (PDF). American Mineralogist. 66: 885–907.
  26. Ravier, Edouard; Martinez, Mathieu; Pellenard, Pierre; Zanella, Alain; Tupinier, Lucie (December 2020). "The milankovitch fingerprint on the distribution and thickness of bedding-parallel veins (beef) in source rocks" (PDF). Marine and Petroleum Geology. 122: 104643. doi:10.1016/j.marpetgeo.2020.104643.
  27. De Yoreo, J. J.; Vekilov, P. G. (2003). "Principles of crystal nucleation and growth". Reviews in Mineralogy and Geochemistry. 54 (1): 57–93. Bibcode:2003RvMG...54...57D. CiteSeerX   10.1.1.324.6362 . doi:10.2113/0540057.
  28. De Yoreo, J.; Gilbert, PUPA; Sommerdijk, N. A. J. M.; Penn, R. L.; Whitelam, S.; Joester, D.; Zhang, H.; Rimer, J. D.; Navrotsky, A.; Banfield, J. F.; Wallace, A. F.; Michel, F. M.; Meldrum, F. C.; Cölfen, H.; Dove, P. M. (2015). "Crystallization by particle attachment in synthetic, biogenic, and geologic environments" (PDF). Science. 349 (6247): aaa6760. doi:10.1126/science.aaa6760. PMID   26228157. S2CID   14742194.
  29. Rodriguez-Blanco, J. D.; Shaw, S.; Benning, L. G. (2011). "The kinetics and mechanisms of amorphous calcium carbonate (ACC) crystallization to calcite, via vaterite". Nanoscale. 3 (1): 265–71. Bibcode:2011Nanos...3..265R. doi:10.1039/C0NR00589D. PMID   21069231.
  30. Rodriguez-Blanco, J. D.; Shaw, S.; Bots, P.; Roncal-Herrero, T.; Benning, L. G. (2012). "The role of pH and Mg on the stability and crystallization of amorphous calcium carbonate". Journal of Alloys and Compounds. 536: S477–S479. doi:10.1016/j.jallcom.2011.11.057.
  31. Bots, P.; Benning, L. G.; Rodriguez-Blanco, J. D.; Roncal-Herrero, T.; Shaw, S. (2012). "Mechanistic Insights into the Crystallization of Amorphous Calcium Carbonate (ACC)". Crystal Growth & Design. 12 (7): 3806–3814. doi:10.1021/cg300676b.
  32. Drake, H.; Astrom, M. E.; Heim, C.; Broman, C.; Astrom, J.; Whitehouse, M.; Ivarsson, M.; Siljestrom, S.; Sjovall, P. (2015). "Extreme 13C depletion of carbonates formed during oxidation of biogenic methane in fractured granite". Nature Communications. 6: 7020. Bibcode:2015NatCo...6.7020D. doi:10.1038/ncomms8020. PMC   4432592 . PMID   25948095.
  33. Porter, S. M. (2007). "Seawater Chemistry and Early Carbonate Biomineralization". Science. 316 (5829): 1302. Bibcode:2007Sci...316.1302P. doi:10.1126/science.1137284. PMID   17540895. S2CID   27418253.
  34. Palmer, Timothy; Wilson, Mark (2004). "Calcite precipitation and dissolution of biogenic aragonite in shallow Ordovician calcite seas". Lethaia. 37 (4): 417–427. doi:10.1080/00241160410002135.
  35. Harper, E.M.; Palmer, T.J.; Alphey, J.R. (1997). "Evolutionary response by bivalves to changing Phanerozoic sea-water chemistry". Geological Magazine. 134 (3): 403–407. Bibcode:1997GeoM..134..403H. doi:10.1017/S0016756897007061.
  36. Meierhenrich, Uwe (2008). Amino acids and the asymmetry of life caught in the act of formation. Berlin: Springer. pp. 76–78. ISBN   9783540768869.

Further reading