Wollastonite

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Wollastonite
WollastoniteUSGOV.jpg
General
Category Inosilicate mineral
Formula
(repeating unit)
Calcium silicate, CaSiO3
Strunz classification 9.DG.05
Crystal system Triclinic
Monoclinic polytype exists
Crystal class Pinacoidal (1)
(same H-M symbol)
Space group P1 (1A polytype)
Unit cell a = 7.925  Å, b = 7.32 Å,
c = 7.065 Å; α = 90.055°,
β = 95.217°, γ = 103.42°; Z = 6
Identification
Color White, colorless or gray
Crystal habit Rare as tabular crystals—commonly massive in lamellar, radiating, compact and fibrous aggregates.
Twinning Common
Cleavage Perfect in two directions at near 90°
Fracture Splintery to uneven
Mohs scale hardness 4.5 to 5.0
Luster Vitreous or dull to pearly on cleavage surfaces
Streak White
Diaphaneity Transparent to translucent
Specific gravity 2.86–3.09
Optical properties Biaxial (-)
Refractive index nα = 1.616–1.640
nβ = 1.628–1.650
nγ = 1.631–1.653
Birefringence δ = 0.015 max
2V angle Measured: 36° to 60°
Melting point 1540 °C
Solubility Soluble in HCl, insoluble in water
Other characteristics

Heat of Formation (@298): -89.61kJ

Gibbs Free Energy: 41.78kJ
References [1] [2] [3] [4]

Wollastonite is a calcium inosilicate mineral (Ca Si O 3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolostone is subjected to high temperature and pressure sometimes in the presence of silica-bearing fluids as in skarns or contact metamorphic rocks. Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite. It is named after the English chemist and mineralogist William Hyde Wollaston (1766–1828).

Calcium Chemical element with atomic number 20

Calcium is a chemical element with symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.

Silicate minerals Rock-forming minerals with predominantly silicate anions

Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of the Earth's crust.

Mineral Element or chemical compound that is normally crystalline and that has been formed as a result of geological processes

A mineral is, broadly speaking, a solid chemical compound that occurs naturally in pure form. A rock may consist of a single mineral, or may be an aggregate of two or more different minerals, spacially segregated into distinct phases. Compounds that occur only in living beings are usually excluded, but some minerals are often biogenic and/or are organic compounds in the sense of chemistry. Moreover, living beings often synthesize inorganic minerals that also occur in rocks.

Contents

Some of the properties that make wollastonite so useful are its high brightness and whiteness, low moisture and oil absorption, and low volatile content. Wollastonite is used primarily in ceramics, friction products (brakes and clutches), metalmaking, paint filler, and plastics.

Despite its chemical similarity to the compositional spectrum of the pyroxene group of minerals—where magnesium and iron substitution for calcium ends with diopside and hedenbergite respectively—it is structurally very different, with a third SiO4 tetrahedron [5] in the linked chain (as opposed to two in the pyroxenes).

Pyroxene A group of inosilicate minerals

The pyroxenes (commonly abbreviated to Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula XY(Si,Al)2O6 where X represents calcium, sodium, iron (II) or magnesium and more rarely zinc, manganese or lithium and Y represents ions of smaller size, such as chromium, aluminium, iron (III), magnesium, cobalt, manganese, scandium, titanium, vanadium or even iron (II). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that cystallize in the orthorhombic system are known as orthopyroxenes.

Magnesium Chemical element with atomic number 12

Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure.

Iron Chemical element with atomic number 26

Iron is a chemical element with symbol Fe and atomic number 26. It is a metal, that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust.

Wollastonite output in 2005 2005wollastonite.PNG
Wollastonite output in 2005

World production data for wollastonite is not available for many countries and those that are available frequently are 2 to 3 years old. Estimated world production of crude wollastonite ore was in the range of 700,000 to 720,000 tonnes in 2016. World reserves of wollastonite were estimated to exceed 100 million tonnes. However, many large deposits have not been surveyed yet.

Tonne Metric unit of mass

The tonne, commonly referred to as the metric ton in the United States and Canada, is a non-SI metric unit of mass equal to 1,000 kilograms or one megagram. It is equivalent to approximately 2,204.6 pounds, 1.102 short tons (US) or 0.984 long tons (UK). Although not part of the SI, the tonne is accepted for use with SI units and prefixes by the International Committee for Weights and Measures.

Large deposits of wollastonite have been identified in China, Finland, India, Mexico, and the United States. Smaller, but significant, deposits have been identified in Canada, Chile, Kenya, Namibia, South Africa, Spain, Sudan, Tajikistan, Turkey, and Uzbekistan. [6]

China Country in East Asia

China, officially the People's Republic of China (PRC), is a country in East Asia and the world's most populous country, with a population of around 1.404 billion. Covering approximately 9,600,000 square kilometers (3,700,000 sq mi), it is the third- or fourth-largest country by total area. Governed by the Communist Party of China, the state exercises jurisdiction over 22 provinces, five autonomous regions, four direct-controlled municipalities, and the special administrative regions of Hong Kong and Macau.

Finland Republic in Northern Europe

Finland, officially the Republic of Finland, is a country in Northern Europe bordering the Baltic Sea, Gulf of Bothnia, and Gulf of Finland, between Norway to the north, Sweden to the northwest, and Russia to the east. Finland is a Nordic country and is situated in the geographical region of Fennoscandia. The capital and largest city is Helsinki. Other major cities are Espoo, Vantaa, Tampere, Oulu and Turku.

India Country in South Asia

India, also known as the Republic of India, is a country in South Asia. It is the seventh largest country by area and with more than 1.3 billion people, it is the second most populous country as well as the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the northeast; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives, while its Andaman and Nicobar Islands share a maritime border with Thailand and Indonesia.

In 2016, the major producers were China (425,000 tonnes), India (185,000 t), United States (Information withheld for commercial reasons but stated to be in third place), Mexico (67,000 t) and Finland (16,000). [6]

In the United States, wollastonite is mined in Willsboro, New York and Gouverneur, New York. Deposits have also been mined commercially in North Western Mexico. [7]

Willsboro, New York Town in New York, United States

Willsboro is a town in Essex County, New York, in the United States, and lies 30 miles (48 km) south of the city of Plattsburgh. As of the 2010 census, the town population was 2,025. The town is named after early landowner William Gilliland.

Gouverneur, New York Town in New York, United States

Gouverneur is a town in St. Lawrence County, New York, United States. The population was 7,085 at the 2010 census. The town is named after statesman and landowner Gouverneur Morris.

Mexico Country in the southern portion of North America

Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the tenth most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.

Uses

Wollastonite has industrial importance worldwide. It is used in many industries, mostly by tile factories which have incorporated it into the manufacturing of ceramic to improve many performance parameters, and this is due to its fluxing properties, freedom from volatile constituents, whiteness, and acicular particle shape. [8]

In ceramics, wollastonite decreases shrinkage and gas evolution during firing, increases green and fired strength, maintains brightness during firing, permits fast firing, and reduces crazing, cracking, and glaze defects.

In metallurgical applications, wollastonite serves as a flux for welding, a source for calcium oxide, a slag conditioner, and to protect the surface of molten metal during the continuous casting of steel.

As an additive in paint, it improves the durability of the paint film, acts as a pH buffer, improves its resistance to weathering, reduces gloss, reduces pigment consumption, and acts as a flatting and suspending agent.

In plastics, wollastonite improves tensile and flexural strength, reduces resin consumption, and improves thermal and dimensional stability at elevated temperatures. Surface treatments are used to improve the adhesion between the wollastonite and the polymers to which it is added.

As a substitute for asbestos in floor tiles, friction products, insulating board and panels, paint, plastics, and roofing products, wollastonite is resistant to chemical attack, inert, stable at high temperatures, and improves flexural and tensile strength. [7] In some industries, it is used in different percentages of impurities, such as its use as a fabricator of mineral wool insulation, or as an ornamental building material. [9]

Plastics and rubber applications were estimated to account for 25% to 35% of U.S. sales in 2009, followed by ceramics with 20% to 25%; paint, 10% to 15%; metallurgical applications, 10% to 15%; friction products, 10% to 15%; and miscellaneous, 10% to 15%. Ceramic applications probably account for 30% to 40% of wollastonite sales worldwide, followed by polymers (plastics and rubber) with 30% to 35% of sales, and paint with 10% to 15% of sales. The remaining sales were for construction, friction products, and metallurgical applications.

The price of raw wollastonite varied in 2008 between US$80 and US$500 per tonne depending on the country and size and shape of the powder particles. [7]

Substitutes

White acicular crystals of wollastonite (field of view 8 mm) from the Central Bohemia Region, Czech Republic Wollastonite-91985.jpg
White acicular crystals of wollastonite (field of view 8 mm) from the Central Bohemia Region, Czech Republic

The acicular nature of many wollastonite products allows it to compete with other acicular materials, such as ceramic fiber, glass fiber, steel fiber, and several organic fibers, such as aramid, polyethylene, polypropylene, and polytetrafluoroethylene in products where improvements in dimensional stability, flexural modulus, and heat deflection are sought.

Wollastonite also competes with several nonfibrous minerals or rocks, such as kaolin, mica, and talc, which are added to plastics to increase flexural strength, and such minerals as barite, calcium carbonate, gypsum, and talc, which impart dimensional stability to plastics.

In ceramics, wollastonite competes with carbonates, feldspar, lime, and silica as a source of calcium and silicon. Its use in ceramics depends on the formulation of the ceramic body and the firing method. [6]

Composition

In a pure CaSiO3, each component forms nearly half of the mineral by weight: 48.3% of CaO and 51.7% of SiO2. In some cases, small amounts of iron (Fe), and manganese (Mn), and lesser amounts of magnesium (Mg) substitute for calcium (Ca) in the mineral formula (e.g., rhodonite). [9] Wollastonite can form a series of solid solutions in the system CaSiO3-FeSiO3, or hydrothermal synthesis of phases in the system MnSiO3-CaSiO3. [8]

Geologic occurrence

Wollastonite skarn with diopside (green), andradite garnet (red) and vesuvianite (dark brown) from the Stanislaw mine near Szklarska Poreba, Izerskie Mountains, Lower Silesia, Poland. WEZUWIAN WOLLASTONIT ANDRADYT 2.jpg
Wollastonite skarn with diopside (green), andradite garnet (red) and vesuvianite (dark brown) from the Stanisław mine near Szklarska Poręba, Izerskie Mountains, Lower Silesia, Poland.

Wollastonite usually occurs as a common constituent of a thermally metamorphosed impure limestone, it also could occur when the silicon is due to metamorphism in contact altered calcareous sediments, or to contamination in the invading igneous rock. In most of these occurrences it is the result of the following reaction between calcite and silica with the loss of carbon dioxide: [8]

CaCO3 + SiO2 → CaSiO3 + CO2

Wollastonite may also be produced in a diffusion reaction in skarn, it develops when limestone within a sandstone is metamorphosed by a dike, which results in the formation of wollastonite in the sandstone as a result of outward migration of Ca. [8]

Structure

Unit cell of triclinic wollastonite-1A Wollastonite-cell.png
Unit cell of triclinic wollastonite-1A
Tetrahedra arrangement within the chains in pyroxenes compared to wollastonite SiO3 chains Pyrox vs Wollast.png
Tetrahedra arrangement within the chains in pyroxenes compared to wollastonite

Wollastonite crystallizes triclinically in space group P1 with the lattice constants a = 7.94  Å, b = 7.32 Å, c = 7.07 Å; α = 90,03°, β = 95,37°, γ = 103,43° and six formula units per unit cell. [10] Wollastonite was once classed structurally among the pyroxene group, because both of these groups have a ratio of Si:O = 1:3. In 1931, Warren and Biscoe showed that the crystal structure of wollastonite differs from minerals of the pyroxene group, and they classified this mineral within a group known as the pyroxenoids. [8] It has been shown that the pyroxenoid chains are more kinked than those of pyroxene group, and exhibit longer repeat distance. The structure of wollastonite contains infinite chains of [SiO4] tetrahedra sharing common vertices, running parallel to the b-axis. The chain motif in wollastonite repeats after three tetrahedra, whereas in pyroxenes only two are needed. The repeat distance in the wollastonite chains is 7.32  Å and equals the length of the crystallographic b-axis.

Molten CaSiO3, maintains a tetrahedral SiO4 local structure, at temperatures up to 2000 ˚C. [11] The nearest neighbour Ca-O coordination decreases from 6.0(2) in the room temperature glass to 5.0(2) in the 1700 ˚C liquid, coincident with an increasing number of longer Ca-O neighbors. [12] [13]

Physical and optical properties

Wollastonite occurs as bladed crystal masses, single crystals can show an acicular particle shape and usually it exhibits a white color, but sometimes cream, grey or very pale green.

The streak of wollastonite is white, its Mohs hardness is 4.5–5 and specific gravity is 2.87–3.09. There are more than one cleavage planes for it, there is a perfect cleavage on {100}, good cleavages on {001}, and {102}, and an imperfect cleavage on {101}. It is common for wollastonite to have a twin axis [010], a composition plane (100), and rarely to have a twin axis [001]. The luster is usually vitreous to pearly. The melting point of wollastonite is about 1540 ˚C.

See also

Related Research Articles

Talc phyllosilicate mineral

Talc is a clay mineral composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often in combination with corn starch, is a widely used substance known as baby powder. This mineral is used as a thickening agent and lubricant, is an ingredient in ceramics, paint and roofing material, and is also one of the main ingredients in many cosmetic products. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage, uneven flat fracture and it is foliated with a two dimensional platy form.

Feldspar A group of rock-forming tectosilicate minerals

Feldspars (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8) are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight.

Amphibole double chain inosilicates

Amphibole is an important group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain SiO
4
tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups.

Diopside Pyroxene mineral

Diopside is a monoclinic pyroxene mineral with composition MgCaSi2O6. It forms complete solid solution series with hedenbergite (FeCaSi2O6) and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class. It has two distinct prismatic cleavages at 87 and 93° typical of the pyroxene series. It has a Mohs hardness of six, a Vickers hardness of 7.7 GPa at a load of 0.98 N, and a specific gravity of 3.25 to 3.55. It is transparent to translucent with indices of refraction of nα=1.663–1.699, nβ=1.671–1.705, and nγ=1.693–1.728. The optic angle is 58° to 63°.

Scapolite marialite-meionite solid solution series

The scapolites (Gr. σκάπος, rod, and λίθος, stone) are a group of rock-forming silicate minerals composed of aluminium, calcium, and sodium silicate with chlorine, carbonate and sulfate. The two endmembers are meionite (Ca4Al6Si6O24CO3) and marialite (Na4Al3Si9O24Cl). Silvialite (Ca,Na)4Al6Si6O24(SO4,CO3) is also a recognized member of the group.

Rhodonite single chain inosilicate mineral

Rhodonite is a manganese inosilicate, (Mn, Fe, Mg, Ca)SiO3 and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. It commonly occurs as cleavable to compact masses with a rose-red color (the name comes from the Greek ῥόδος rhodos, rosy), often tending to brown because of surface oxidation.

Hedenbergite pyroxene mineral

Hedenbergite, CaFeSi2O6, is the iron rich end member of the pyroxene group having a monoclinic crystal system. The mineral is extremely rarely found as a pure substance, and usually has to be synthesized in a lab. It was named in 1819 after M.A. Ludwig Hedenberg, who was the first to define hedenbergite as a mineral. Contact metamorphic rocks high in iron are the primary geologic setting for hedenbergite. This mineral is unique because it can be found in chondrites and skarns (calc–silicate metamorphic rocks). Since it is a member of the pyroxene family, there is a great deal of interest in its importance to general geologic processes.

Celsian feldspar, mineral

Celsian is an uncommon feldspar mineral, barium aluminosilicate, BaAl2Si2O8. The mineral occurs in contact metamorphic rocks with significant barium content. Its crystal system is monoclinic, and it is white, yellow, or transparent in appearance. In pure form, it is transparent. Synthetic barium aluminosilicate is used as a ceramic in dental fillings and other applications.

Afwillite nesosilicate mineral

Afwillite is a calcium hydroxide nesosilicate mineral with formula Ca3(SiO3OH)2·2H2O. It occurs as glassy, colorless to white prismatic monoclinic crystals. Its Mohs scale hardness is between 3 and 4. It occurs as an alteration mineral in contact metamorphism of limestone. It occurs in association with apophyllite, natrolite, thaumasite, merwinite, spurrite, gehlenite, ettringite, portlandite, hillebrandite, foshagite, brucite and calcite.

Clinozoisite epidote supergroup, sorosilicate mineral

Clinozoisite is a complex calcium aluminium sorosilicate mineral with formula: Ca2Al3(Si2O7)(SiO4)O(OH). It forms a continuous solid solution series with epidote by substitution of iron(III) in the aluminium (m3 site) and is also called aluminium epidote.

Pyroxferroite inosilicate mineral

Pyroxferroite (Fe2+,Ca)SiO3 is a single chain inosilicate. It is mostly composed of iron, silicon and oxygen, with smaller fractions of calcium and several other metals. Together with armalcolite and tranquillityite, it is one of the three minerals which were discovered on the Moon. It was then found in Lunar and Martian meteorites as well as a mineral in the Earth's crust. Pyroxferroite can also be produced by annealing synthetic clinopyroxene at high pressures and temperatures. The mineral is metastable and gradually decomposes at ambient conditions, but this process can take billions of years.

Alite is an impure form of tricalcium silicate, Ca3SiO5, sometimes formulated as 3CaO·SiO2 (C3S in cement chemist notation, CCN) with typically 3-4% of substituent oxides. It is the major, and characteristic, mineral phase in Portland cement. The name was given by Törneborn in 1897 to a crystal identified in microscopic investigation of Portland cement. Alite is a name in common use in the cement industry, but it is very rare in nature (known as hatrurite).

Filler (materials)

Filler materials are particles added to resin or binders that can improve specific properties, make the product cheaper or a mixture of both. The two largest segments for filler material use is elastomers and plastics. Worldwide, more than 53 million tons of fillers are used every year in different application areas, such as paper, plastics, rubber, paints, coatings, adhesives and sealants. As such, fillers, produced by more than 700 companies, rank among the world's major raw materials and are contained in a variety of goods for daily consumer needs. The top filler materials used are ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin, talc, and carbon black. Filler materials can affect the tensile strength, toughness, heat resistance, color, clarity etc. A good example of this is the addition of talc to polypropylene. Most of the filler materials used in plastics are mineral or glass based filler materials. There are two main subgroups of filler materials: particulates and fibers. Particulates are small particles of filler which are mixed in the matrix where size and aspect ratio are important. Fibers are small circular strands that can be very long and have very high aspect ratios.

Calcium silicate hydrate is the main product of the hydration of Portland cement and is primarily responsible for the strength in cement based materials.

Bustamite single chain inosilicate mineral

Bustamite is a calcium manganese inosilicate (chain silicate) and a member of the wollastonite group. Magnesium, zinc and iron are common impurities substituting for manganese. Bustamite is the high-temperature polymorph of CaMnSi2O6 and johannsenite is the low temperature polymorph. The inversion takes place at 830 °C (1,530 °F), but may be very slow.
Bustamite could be confused with light-colored rhodonite or pyroxmangite, but both these minerals are biaxial (+) whereas bustamite is biaxial (-).

Cuspidine is a fluorine bearing calcium silicate mineral (sorosilicate) with formula: Ca4(Si2O7)(F,OH)2. Cuspidine crystallizes in the monoclinic crystal system and occurs as acicular to spear shaped pale red to light brown crystals. It is a member of the wöhlerite group.

Dorrite is a silicate mineral that is isostructural to the aenigmatite group. Although it is most chemically similar to the mineral rhönite [Ca2Mg5Ti(Al2Si4)O20], the lack of titanium (Ti) and presence of Fe3+ influenced dorrite's independence. Dorrite is named for Dr. John (Jack) A. Dorr, a late professor at the University of Michigan that researched in outcrops where dorrite was found in 1982. This mineral is sub-metallic resembling colors of brownish-black, dark brown, to reddish brown.

References

PD-icon.svg This article incorporates public domain material  from the  United States Geological Survey document:  "Wollastonite". 

  1. Wollastonite, Mindat
  2. Wollastonite, Webmineral
  3. Wollastonite, Handbook of Mineralogy
  4. American Mineralogist, V. 79, pp. 134-144, 1994
  5. William Alexander Deer; Robert Andrew Howie; J. Zussman (1992). An introduction to the rock-forming minerals . Longman Scientific & Technical. ISBN   978-0-470-21809-9.
  6. 1 2 3 Wollastonite, USGS Mineral Commodity Summaries 2017
  7. 1 2 3 Robert L. Virta Wollastonite, USGS 2009 Minerals Yearbook (October 2010)
  8. 1 2 3 4 5 Deer, Howie and Zussman. Rock Forming Minerals; Single Chain Silicates, Vol. 2A, Second Edition, London, The Geological Society, 1997.
  9. 1 2 Andrews, R. W. Wollastonite. London, Her Majesty's Stationery Office, 1970.
  10. Buerger, M. J. (1961). "The crystal structures of wollastonite and pectolite". Proceedings of the National Academy of Sciences. 47 (12): 1884–1888. Bibcode:1961PNAS...47.1884B. doi:10.1073/pnas.47.12.1884. JSTOR   71064. PMC   223235 Lock-green.svg.
  11. Benmore, C.J.; et al. (2010). "Temperature-dependent structural heterogeneity in calcium silicate liquids". Phys. Rev. B (82): 224202. Bibcode:2010PhRvB..82v4202B. doi:10.1103/PhysRevB.82.224202.
  12. Skinner, L.B.; et al. (2012). "Structure of Molten CaSiO3: Neutron Diffraction Isotope Substitution with Aerodynamic Levitation and Molecular Dynamics Study". J. Phys. Chem. B. 116 (45): 13439–13447. doi:10.1021/jp3066019.
  13. Eckersley, M.C.; et al. (1988). "Structural ordering in a calcium silicate glass". Nature. 355: 525–527. Bibcode:1988Natur.335..525E. doi:10.1038/335525a0.