Extraterrestrial diamonds

Last updated

Although diamonds on Earth are rare, extraterrestrial diamonds (diamonds formed outside of Earth) are very common. Diamonds so small that they contain only about 2000 carbon atoms are abundant in meteorites, and some of them formed in stars before the Solar System existed. [1] High pressure experiments suggest large amounts of diamonds are formed from methane on the ice giant planets Uranus and Neptune, while some planets in other planetary systems may be almost pure diamond. [2] Diamonds are also found in stars and may have been the first mineral ever to have formed.

Contents

Meteorites

Artist's conception of a multitude of tiny diamonds next to a hot star. SpaceNanoDiamonds.jpg
Artist's conception of a multitude of tiny diamonds next to a hot star.

In 1987, a team of scientists examined some primitive meteorites and found grains of diamond about 2.5 nanometers in diameter (nanodiamonds). Trapped in them were noble gases whose isotopic signature indicated they came from outside the Solar System. Analyses of additional primitive meteorites also found nanodiamonds. The record of their origins was preserved despite a long and violent history that started when they were ejected from a star into the interstellar medium, went through the formation of the Solar System, were incorporated into a planetary body that was later broken up into meteorites, and finally crashed on the Earth's surface. [3]

In meteorites, nanodiamonds make up about 3 percent of the carbon and 0.04% of the total mass. [4] [3] Grains of silicon carbide and graphite also have anomalous isotopic patterns. Collectively they are known as presolar grains or stardust and their properties constrain models of nucleosynthesis in giant stars and supernovae. [5]

It is unclear how many nanodiamonds in meteorites are really from outside the Solar System. Only a very small fraction of them contain noble gases of presolar origin, and until recently it was not possible to study them individually. On average, the ratio of carbon-12 to carbon-13 matches that of the Earth's atmosphere, while that of nitrogen-14 to nitrogen-15 matches the Sun. Techniques such as atom probe tomography will make it possible to examine individual grains, but due to the limited number of atoms, the isotopic resolution is limited. [5]

If most nanodiamonds did form in the Solar System, that raises the question of how this is possible. On the Earth's surface, graphite is the stable carbon mineral, while larger diamonds can only be formed in the kind of temperatures and pressures that are found deep in the mantle. However, nanodiamonds are close to molecular size: one with a diameter of 2.8 nm, the median size, contains about 1800 carbon atoms. [5] In very small minerals, surface energy is important and diamonds are more stable than graphite because the diamond structure is more compact. The crossover in stability is at between 1 and 5 nm. At even smaller sizes, a variety of other forms of carbon such as fullerenes can be found, as well as diamond cores wrapped in fullerenes. [3]

The most carbon-rich meteorites, with abundances up to 0.7% by mass, are ureilites. [6] :241 These have no known parent body and their origin is controversial. [7] Diamonds are common in highly shocked ureilites, and most are thought to have been formed by the shock of the impact with either Earth or other bodies in space. [6] [8] :264 However, much larger diamonds were found in fragments of a meteorite called Almahata Sitta, found in the Nubian Desert of Sudan. They contained inclusions of iron- and sulfur-bearing minerals, the first inclusions to be found in extraterrestrial diamonds. [9] They were dated at 4.5 billion-year-old crystals and were formed at pressures greater than 20 gigapascals. The authors of a 2018 study concluded that they must have come from a protoplanet, no longer intact, with a size between that of the moon and Mars. [10] [11]

Infrared emissions from space, observed by the Infrared Space Observatory and the Spitzer Space Telescope, has made it clear that carbon-containing molecules are ubiquitous in space. These include polycyclic aromatic hydrocarbons (PAHs), fullerenes and diamondoids (hydrocarbons that have the same crystal structure as diamond). [3] If dust in space has a similar concentration, a gram of it would carry up to 10 quadrillion of them, [4] but so far there is little evidence for their presence in the interstellar medium; they are difficult to tell apart from diamondoids. [3]

Planets

Solar System

Uranus, imaged by Voyager 2 in 1986. Uranus (Edited).jpg
Uranus, imaged by Voyager 2 in 1986.

In 1981, Martin Ross wrote a paper titled "The ice layer in Uranus and Neptune—diamonds in the sky?" in which he proposed that huge quantities of diamonds might be found in the interior of these planets. At Lawrence Livermore, he had analyzed data from shock-wave compression of methane (CH4) and found that the extreme pressure separated the carbon atom from the hydrogen, freeing it to form diamond. [12] [13]

Theoretical modeling by Sandro Scandolo and others predicted that diamonds would form at pressures over 300 gigapascals (GPa), but even at lower pressures methane would be disrupted and form chains of hydrocarbons. High pressure experiments at the University of California Berkeley using a diamond anvil cell found both structures at only 50 GPa and a temperature of 2500 kelvins, equivalent to depths of 7000 kilometers below Neptune's cloud tops. Another experiment at the Geophysical Laboratory saw methane becoming unstable at only 7 GPa and 2000 kelvins. After forming, denser diamonds would sink. This "diamond rain" would convert potential energy into heat and help drive the convection that generates Neptune's magnetic field. [14] [12] [15]

There are some uncertainties in how well the experimental results apply to Uranus and Neptune. Water and hydrogen mixed with the methane may alter the chemical reactions. [14] A physicist at the Fritz Haber Institute in Berlin showed that the carbon on these planets is not concentrated enough to form diamonds from scratch. A proposal that diamonds may also form in Jupiter and Saturn, where the concentration of carbon is far lower, was considered unlikely because the diamonds would quickly dissolve. [16]

Experiments looking for conversion of methane to diamonds found weak signals and did not reach the temperatures and pressures expected in Uranus and Neptune. However, a recent experiment used shock heating by lasers to reach temperatures and pressures expected at a depth of 10,000 kilometers below the surface of Uranus. When they did this to polystyrene, nearly every carbon atom in the material was incorporated into diamond crystals within a nanosecond. [17] [18]

Extrasolar

On Earth, the natural form of silicon carbide is a rare mineral, moissanite. Moissanite-USGS-20-1002a.jpg
On Earth, the natural form of silicon carbide is a rare mineral, moissanite.

In the Solar System the rocky planets Mercury, Venus, Earth and Mars are 70% to 90% silicates by mass. By contrast, stars with a high ratio of carbon to oxygen may be orbited by planets that are mostly carbides, with the most common material being silicon carbide. This has a higher thermal conductivity and a lower thermal expansivity than silicates. This would result in more rapid conductive cooling near the surface, but lower down the convection could be at least as vigorous as that in silicate planets. [20]

One such planet is PSR J1719-1438 b, companion to a millisecond pulsar. It has a density at least twice that of lead, and may be composed mainly of ultra-dense diamond. It is believed to be the remnant of a white dwarf after the pulsar stripped away more than 99 percent of its mass. [2] [21] [22]

Another planet, 55 Cancri e, has been called a "super-Earth" because, like Earth, it is a rocky planet orbiting a sun-like star, but it has twice the radius and eight times the mass. The researchers who discovered it in 2012 concluded that it was carbon-rich, making an abundance of diamond likely. [23] However, later analyses using multiple measures for the star's chemical composition indicated that the star has 25 percent more oxygen than carbon. This makes it less likely that the planet itself is a carbon planet. [24]

Stars

It has been proposed that diamonds exist in carbon-rich stars, particularly white dwarfs; Carbonado, a polycrystalline mix of diamond, graphite, and amorphous carbon, which is one of the hardest natural forms of carbon, is also present, [25] and could come from supernovae and white dwarfs. [26] The white dwarf BPM 37093, located 50 light-years (4.7×1014 km) away in the constellation Centaurus, has a diameter of 2,500 miles (4,000 km), and may have a diamond core, which would make it one of the largest diamonds in the universe. For this reason it was given the nickname Lucy. [27] [28]

In 2008, Robert Hazen and colleagues at the Carnegie Institution in Washington, D.C. published a paper, "Mineral evolution", in which they explored the history of mineral formation and found that the diversity of minerals has changed over time as the conditions have changed. Before the Solar System formed, only a small number of minerals were present, including diamonds and olivine. [29] [30] The first minerals may have been small diamonds formed in stars because stars are rich in carbon and diamonds form at a higher temperature than any other known mineral. [31]

See also

Related Research Articles

<span class="mw-page-title-main">Carbon</span> Chemical element with atomic number 6 (C)

Carbon is a chemical element; it has symbol C and atomic number 6. It is nonmetallic and tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three isotopes occur naturally, 12C and 13C being stable, while 14C is a radionuclide, decaying with a half-life of 5,700 years. Carbon is one of the few elements known since antiquity.

<span class="mw-page-title-main">Diamond</span> Form of carbon

Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond as a form of carbon is a tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.

<span class="mw-page-title-main">Giant planet</span> Planet much larger than the Earth

A giant planet, sometimes referred to as a jovian planet, is a diverse type of planet much larger than Earth. Giant planets are usually primarily composed of low-boiling point materials (volatiles), rather than rock or other solid matter, but massive solid planets can also exist. There are four such planets in the Solar System: Jupiter, Saturn, Uranus, and Neptune. Many extrasolar giant planets have been identified.

<span class="mw-page-title-main">Lonsdaleite</span> Hexagonal lattice allotrope of carbon

Lonsdaleite, also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with a hexagonal lattice, as opposed to the cubical lattice of conventional diamond. It is found in nature in meteorite debris; when meteors containing graphite strike the Earth, the immense heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified in 1967 from the Canyon Diablo meteorite, where it occurs as microscopic crystals associated with ordinary diamond.

<span class="mw-page-title-main">Uranus</span> Seventh planet from the Sun

Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which astronomy calls "ice" or volatiles. The planet's atmosphere has a complex layered cloud structure and has the lowest minimum temperature of all the Solar System's planets. It has a marked axial tilt of 82.23° with a retrograde rotation period of 17 hours and 14 minutes. This means that in an 84-Earth-year orbital period around the Sun, its poles get around 42 years of continuous sunlight, followed by 42 years of continuous darkness.

<span class="mw-page-title-main">Natural abundance</span> Relative proportion of an isotope as found in nature

In physics, natural abundance (NA) refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table. The abundance of an isotope varies from planet to planet, and even from place to place on the Earth, but remains relatively constant in time.

<span class="mw-page-title-main">Presolar grains</span> Very old dust in space

Presolar grains are interstellar solid matter in the form of tiny solid grains that originated at a time before the Sun was formed. Presolar grains formed within outflowing and cooling gases from earlier presolar stars. The study of presolar grains is typically considered part of the field of cosmochemistry and meteoritics.

<span class="mw-page-title-main">Cosmochemistry</span> Study of the chemical composition of matter in the universe

Cosmochemistry or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions. This is done primarily through the study of the chemical composition of meteorites and other physical samples. Given that the asteroid parent bodies of meteorites were some of the first solid material to condense from the early solar nebula, cosmochemists are generally, but not exclusively, concerned with the objects contained within the Solar System.

<span class="mw-page-title-main">Moissanite</span> Silicon carbide mineral

Moissanite is naturally occurring silicon carbide and its various crystalline polymorphs. It has the chemical formula SiC and is a rare mineral, discovered by the French chemist Henri Moissan in 1893. Silicon carbide or moissanite is useful for commercial and industrial applications due to its hardness, optical properties and thermal conductivity.

<span class="mw-page-title-main">Allotropes of carbon</span> Materials made only out of carbon

Carbon is capable of forming many allotropes due to its valency (tetravalent). Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger-scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures. Around 500 hypothetical 3‑periodic allotropes of carbon are known at the present time, according to the Samara Carbon Allotrope Database (SACADA).

<span class="mw-page-title-main">Carbon planet</span> Hypothetical type of planet that contains more carbon than oxygen

A carbon planet is a hypothetical type of planet that contains more carbon than oxygen. Carbon is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen.

<span class="mw-page-title-main">Carbonaceous chondrite</span> Class of chondritic meteorites

Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small proportion (4.6%) of meteorite falls.

<span class="mw-page-title-main">Carbonado</span> Impure form of polycrystalline diamond consisting of diamond, graphite, and amorphous carbon

Carbonado, commonly known as black diamond, is one of the toughest forms of natural diamond. It is an impure, high-density, micro-porous form of polycrystalline diamond consisting of diamond, graphite, and amorphous carbon, with minor crystalline precipitates filling pores and occasional reduced metal inclusions. Titanium nitride has been found in carbonado. It is found primarily in alluvial deposits where it is most prominent in mid-elevation equatorial regions such as Central African Republic and in Brazil, where the vast majority of carbonado diamondites have been found. Its natural colour is black or dark grey, and it is more porous than other diamonds.

<span class="mw-page-title-main">Cosmic dust</span> Dust floating in space

Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm), such as micrometeoroids and meteoroids. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust, and circumplanetary dust. There are several methods to obtain space dust measurement.

<span class="mw-page-title-main">Extraterrestrial atmosphere</span> Area of astronomical research

The study of extraterrestrial atmospheres is an active field of research, both as an aspect of astronomy and to gain insight into Earth's atmosphere. In addition to Earth, many of the other astronomical objects in the Solar System have atmospheres. These include all the giant planets, as well as Mars, Venus and Titan. Several moons and other bodies also have atmospheres, as do comets and the Sun. There is evidence that extrasolar planets can have an atmosphere. Comparisons of these atmospheres to one another and to Earth's atmosphere broaden our basic understanding of atmospheric processes such as the greenhouse effect, aerosol and cloud physics, and atmospheric chemistry and dynamics.

<span class="mw-page-title-main">Neptune</span> Eighth planet from the Sun

Neptune is the eighth and farthest known planet from the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to its fellow ice giant Uranus, Neptune is slightly more massive, but denser and smaller. Being composed primarily of gases and liquids, it has no well-defined solid surface, and orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units. It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune's trident.

<span class="mw-page-title-main">Ureilite</span> Rare type of stony meteorite

Ureilite is a rare type of stony meteorite that has a unique mineralogical composition very different from that of other stony meteorites. This dark grey or brownish meteorite type is named after the village Novy Urey (Cyrillic: Новый Урей), Mordovia Republic of Russia, where a meteorite of this type fell on 4 September 1886. Notable ureilites are the Novo Urei and the Goalpara, also named for the town in which it landed (Goalpara, Assam India). On 7 October 2008, tiny asteroid 2008 TC3 entered Earth's atmosphere and exploded an estimated 37 kilometres (23 mi) above the Nubian Desert in Sudan. Fragments of this asteroid were recovered the following December and were found to be ureilite. Scientists have discovered amino acids in meteorite 2008 TC3 where none were expected, taking into account high temperatures reached in the explosion of about 1000 °C.

CI chondrites, also called C1 chondrites or Ivuna-type carbonaceous chondrites, are a group of rare carbonaceous chondrite, a type of stony meteorite. They are named after the Ivuna meteorite, the type specimen. CI chondrites have been recovered in France, Canada, India, and Tanzania. Their overall chemical composition closely resembles the elemental composition of the Sun, more so than any other type of meteorite.

The geochemistry of carbon is the study of the transformations involving the element carbon within the systems of the Earth. To a large extent this study is organic geochemistry, but it also includes the very important carbon dioxide. Carbon is transformed by life, and moves between the major phases of the Earth, including the water bodies, atmosphere, and the rocky parts. Carbon is important in the formation of organic mineral deposits, such as coal, petroleum or natural gas. Most carbon is cycled through the atmosphere into living organisms and then respirated back into the atmosphere. However an important part of the carbon cycle involves the trapping of living matter into sediments. The carbon then becomes part of a sedimentary rock when lithification happens. Human technology or natural processes such as weathering, or underground life or water can return the carbon from sedimentary rocks to the atmosphere. From that point it can be transformed in the rock cycle into metamorphic rocks, or melted into igneous rocks. Carbon can return to the surface of the Earth by volcanoes or via uplift in tectonic processes. Carbon is returned to the atmosphere via volcanic gases. Carbon undergoes transformation in the mantle under pressure to diamond and other minerals, and also exists in the Earth's outer core in solution with iron, and may also be present in the inner core.

CM chondrites are a group of chondritic meteorites which resemble their type specimen, the Mighei meteorite. The CM is the most commonly recovered group of the 'carbonaceous chondrite' class of meteorites, though all are rarer in collections than ordinary chondrites.

References

  1. Daulton, T. L. (2006). "Extraterrestrial Nanodiamonds in the Cosmos". (Chapter II) in "Ultrananocrystalline Diamond: Synthesis, Properties, and Applications" editors O. Shenderova and D. Gruen. pp. 23–78.
  2. 1 2 Max Planck Institute for Radio Astronomy (25 August 2011). "A planet made of diamond". Astronomy magazine. Retrieved 25 September 2017.
  3. 1 2 3 4 5 Tielens, A. G. G. M. (12 July 2013). "The molecular universe". Reviews of Modern Physics. 85 (3): 1021–1081. Bibcode:2013RvMP...85.1021T. doi:10.1103/RevModPhys.85.1021.
  4. 1 2 Vu, Linda (26 February 2008). "Spitzer's Eyes Perfect for Spotting Diamonds in the Sky". JPL News. Jet Propulsion Laboratory. Archived from the original on 9 October 2016. Retrieved 23 September 2017.
  5. 1 2 3 Davis, A. M. (21 November 2011). "Stardust in meteorites". Proceedings of the National Academy of Sciences. 108 (48): 19142–19146. Bibcode:2011PNAS..10819142D. doi: 10.1073/pnas.1013483108 . PMC   3228455 . PMID   22106261.
  6. 1 2 Kallenbach, R.; Encrenaz, Thérèse; Geiss, Johannes; Mauersberger, Konrad; Owen, Tobias; Robert, François, eds. (2003). Solar System History from Isotopic Signatures of Volatile Elements Volume Resulting from an ISSI Workshop 14–18 January 2002, Bern, Switzerland. Dordrecht: Springer Netherlands. ISBN   9789401001458.
  7. "Ureilites". Northern Arizona Meteorite Laboratory. Northern Arizona University. Retrieved 23 April 2018.
  8. Hutchison, Robert (2006). Meteorites : a petrologic, chemical, and isotopic synthesis. Cambridge: Cambridge University Press. ISBN   9780521035392.
  9. Gibbens, Sarah (17 April 2018). "Diamonds From Outer Space Formed Inside a Long-Lost Planet". National Geographic. Archived from the original on 18 April 2018. Retrieved 23 April 2018.
  10. Salazar, Doris Elin (18 April 2018). "Diamonds in Meteorite May Come from a Lost Planet". Scientific American. Retrieved 23 April 2018.
  11. Nabiei, Farhang; Badro, James; Dennenwaldt, Teresa; Oveisi, Emad; Cantoni, Marco; Hébert, Cécile; El Goresy, Ahmed; Barrat, Jean-Alix; Gillet, Philippe (17 April 2018). "A large planetary body inferred from diamond inclusions in a ureilite meteorite". Nature Communications. 9 (1): 1327. Bibcode:2018NatCo...9.1327N. doi:10.1038/s41467-018-03808-6. PMC   5904174 . PMID   29666368.
  12. 1 2 Scandolo, Sandro; Jeanloz, Raymond (November–December 2003). "The Centers of Planets: In laboratories and computers, shocked and squeezed matter turns metallic, coughs up diamonds and reveals Earth's white-hot center". American Scientist. 91 (6): 516–525. Bibcode:2003AmSci..91..516S. doi:10.1511/2003.38.905. JSTOR   27858301. S2CID   120975663.
  13. Ross, Marvin (30 July 1981). "The ice layer in Uranus and Neptune—diamonds in the sky?". Nature. 292 (5822): 435–436. Bibcode:1981Natur.292..435R. doi:10.1038/292435a0. S2CID   4368476.
  14. 1 2 Kerr, R. A. (1 October 1999). "Neptune May Crush Methane Into Diamonds". Science. 286 (5437): 25. doi:10.1126/science.286.5437.25a. PMID   10532884. S2CID   42814647.
  15. Kaplan, Sarah (25 August 2017). "It rains solid diamonds on Uranus and Neptune". The Washington Post . Retrieved 16 October 2017.
  16. McKee, Maggie (9 October 2013). "Diamond drizzle forecast for Saturn and Jupiter". Nature News. doi: 10.1038/nature.2013.13925 . S2CID   124933499.
  17. Cartier, Kimberly (15 September 2017). "Diamonds Really Do Rain on Neptune, Experiments Conclude". Eos. doi: 10.1029/2017EO082223 .
  18. Kraus, D.; et al. (September 2017). "Formation of diamonds in laser-compressed hydrocarbons at planetary interior conditions". Nature Astronomy. 1 (9): 606–611. Bibcode:2017NatAs...1..606K. doi:10.1038/s41550-017-0219-9. S2CID   46945778.
  19. Di Pierro S.; Gnos E.; Grobety B.H.; Armbruster T.; Bernasconi S.M. & Ulmer P. (2003). "Rock-forming moissanite (natural α-silicon carbide)". American Mineralogist. 88 (11–12): 1817–21. Bibcode:2003AmMin..88.1817D. doi:10.2138/am-2003-11-1223. S2CID   128600868.
  20. Nisr, C.; Meng, Y.; MacDowell, A. A.; Yan, J.; Prakapenka, V.; Shim, S.-H. (January 2017). "Thermal expansion of SiC at high pressure-temperature and implications for thermal convection in the deep interiors of carbide exoplanets". Journal of Geophysical Research: Planets. 122 (1): 124–133. Bibcode:2017JGRE..122..124N. doi: 10.1002/2016JE005158 . OSTI   1344574.
  21. Perkins, Sid (25 August 2011). "Diamond Planet Orbits a Pulsar". ScienceShots. American Association for the Advancement of Science. Retrieved 25 September 2017.
  22. Lemonick, Michael (26 August 2011). "Scientists Discover a Diamond as Big as a Planet". Time. Retrieved 2 September 2017.
  23. Duffy, T. S.; Madhusudhan, N.; Lee, K.K.M. (2015). "2.07 Mineralogy of super-Earth planets". In Gerald, Schubert (ed.). Treatise on Geophysics. Elsevier. pp. 149–178. ISBN   9780444538031.
  24. Gannon, Megan (14 October 2013). "'Diamond' Super-Earth Planet May Not Be So Glam". Space.com . Retrieved 25 September 2017.
  25. Heaney, P. J.; Vicenzi, E. P.; De, S. (2005). "Strange Diamonds: the Mysterious Origins of Carbonado and Framesite". Elements. 1 (2): 85. Bibcode:2005Eleme...1...85H. doi:10.2113/gselements.1.2.85. S2CID   128888404.
  26. Shumilova, T.G.; Tkachev, S.N.; Isaenko, S.I.; Shevchuk, S.S.; Rappenglück, M.A.; Kazakov, V.A. (April 2016). "A "diamond-like star" in the lab. Diamond-like glass". Carbon. 100: 703–709. Bibcode:2016Carbo.100..703S. doi: 10.1016/j.carbon.2016.01.068 .
  27. "This Valentine's Day, Give The Woman Who Has Everything The Galaxy's Largest Diamond". Center for Astrophysics. Retrieved 5 May 2009.
  28. "Lucy's in the Sky with Diamonds: Meet the Most Expensive Star Ever Found". Futurism. 12 June 2014. Retrieved 20 May 2019.
  29. "How rocks evolve". The Economist . 13 November 2008. Retrieved 26 September 2017.
  30. Hazen, R. M.; Papineau, D.; Bleeker, W.; Downs, R. T.; Ferry, J. M.; McCoy, T. J.; Sverjensky, D. A.; Yang, H. (1 November 2008). "Mineral evolution". American Mineralogist. 93 (11–12): 1693–1720. Bibcode:2008AmMin..93.1693H. doi:10.2138/am.2008.2955. S2CID   27460479.
  31. Wei-Haas, Maya (13 January 2016). "Life and Rocks May Have Co-Evolved on Earth". Smithsonian . Retrieved 26 September 2017.