# Spinel

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Mineral or gemstone

For the larger class of minerals, see [Spinel group](/source/Spinel_group). For the Russian painter, see [Joseph Spinel](/source/Joseph_Spinel). For the Steven Universe character, see [List of Steven Universe characters § Spinel](/source/List_of_Steven_Universe_characters#Spinel).

Spinel Small spinel crystal on top of a white calcite from Mogok, Myanmar, measuring 1.5 × 1.1 × 1 cm in size General Category Oxide minerals Spinel group Spinel structural group Formula MgAl 2O 4 IMA symbol Spl[1] Strunz classification 4.BB.05 Crystal system Cubic Crystal class Hextetrahedral (43m) H–M symbol: (43m)[2][3][4] Space group F 4 3 m (No. 216) Unit cell a = 8.0898(9) Å; Z = 8 Identification Color Various: red, pink, blue, lavender / violet, dark green, brown, black, clear Crystal habit Octahedral or flat triangular plates caused by twinning Twinning common Cleavage None Fracture Conchoidal Mohs scale hardness 7.5–8.0 Luster Vitreous Streak White Diaphaneity Transparent to opaque Specific gravity (Depending on the composition) The rare Zn-rich spinel can be as high as 4.40, otherwise it averages from 3.58 to 3.61. Optical properties Isotropic Refractive index 1.719 Pleochroism Absent Solubility None Other characteristics Weakly to medium magnetic; sometimes fluorescent (natural: sometimes red; synthetic: red) References [5][6]

**Spinel** ([/spɪˈnɛl, ˈspɪnəl/](https://en.wikipedia.org/wiki/Help:IPA/English)[7]) is the [magnesium](/source/Magnesium)/[aluminium](/source/Aluminium) member of the larger [spinel group](/source/Spinel_group) of minerals. It has the formula MgAl 2O 4 in the [cubic crystal system](/source/Cubic_crystal_system). The name comes from the Latin word *spinella*, a diminutive form of *spine,* in reference to its pointed crystals.[5]

## Properties

Spinel crystallizes in the isometric system; common crystal forms are [octahedra](/source/Octahedron), usually [twinned](/source/Crystal_twinning). It has no true [cleavage](/source/Cleavage_(crystal)), but shows an octahedral [parting](/source/Parting_(crystal)) and a [conchoidal fracture](/source/Conchoidal_fracture).[8] Its [hardness](/source/Mohs_scale_of_mineral_hardness) is 8, its [specific gravity](/source/Specific_gravity) is 3.5–4.1, and it is transparent to opaque with a vitreous to dull [luster](/source/Lustre_(mineralogy)). It may be colorless, but usually comes in shades of red, [lavender](/source/Lavender_(color)), blue, green, brown, black, or yellow.[9] Chromium(III) causes the red color in spinel from Burma.[10]

Polyhedral representation of spinel MgAl2O4

## History

Some spinels are among the most famous gemstones; these include the [Black Prince's Ruby](/source/Black_Prince's_Ruby) and the [Timur Ruby](/source/Timur_Ruby) in the British [Crown Jewels](/source/Crown_Jewels_of_the_United_Kingdom),[11] and the "Côte de Bretagne", formerly from the French Crown jewels.[12] The [Samarian Spinel](/source/Samarian_Spinel), the largest known spinel in the world, weighs 500 carats (100 g).[13]

## Nomenclature

The transparent red spinels were called spinel-rubies[14] or balas rubies.[15] Before the development of modern science and the establishment of a formal definition of "[ruby](/source/Ruby)", the name was also applied to spinels. [16] "Balas" derives from Balascia, the ancient name for [Badakhshan](/source/Badakhshan), a region in central [Asia](/source/Asia) situated in the upper valley of the [Panj River](/source/Panj_River), one of the principal tributaries of the [Oxus River](/source/Oxus_River). However, "Balascia" itself may be derived from [Sanskrit](/source/Sanskrit) *bālasūryaka*, which translates as "crimson-coloured morning sun".[17] Mines in the [Gorno Badakhshan](/source/Gorno_Badakhshan) region of present-day [Tajikistan](/source/Tajikistan) constituted for centuries the main source for red and pink spinels.[16]

## Occurrence

### Geologic occurrence

Spinel is found as a [metamorphic mineral](/source/Metamorphic_rock) in metamorphosed [limestones](/source/Limestone) and silica-poor [mudstones](/source/Mudstone).[9] It also occurs as a primary mineral in rare mafic [igneous rocks](/source/Igneous_rock); in these igneous rocks, the [magmas](/source/Magma) are relatively deficient in [alkalis](/source/Alkali) relative to [aluminium](/source/Aluminium), and aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel. This is why spinel and [ruby](/source/Ruby) are often found together. The spinel petrogenesis in mafic magmatic rocks is strongly debated, but certainly results from mafic magma interaction with more evolved magma [18] or rock (e.g. gabbro, troctolite).[19][20]

Spinel, (Mg,Fe)(Al,Cr)2O4, is common in [peridotite](/source/Peridotite) in the uppermost [Earth's mantle](/source/Earth's_mantle), between approximately 20 km to approximately 120 km, possibly to lower depths depending on the chromium content.[21] At significantly shallower depths, above the [Moho](/source/Mohorovi%C4%8Di%C4%87_discontinuity), calcic [plagioclase](/source/Plagioclase) is the more stable aluminous mineral in peridotite while [garnet](/source/Garnet) is the stable phase deeper in the mantle below the spinel stability region.[22]

Spinel, (Mg,Fe)Al2O4, is a common mineral in the [Ca-Al-rich inclusions](/source/Ca-Al-rich_inclusion) (CAIs) in some [chondritic meteorites](/source/Chondrite).[23]

### Geographical occurrence

Spinel has long been found in the [gemstone](/source/Gemstone)-bearing gravel of [Sri Lanka](/source/Sri_Lanka) and in [limestones](/source/Limestone) of the Badakshan Province in modern-day [Afghanistan](/source/Afghanistan) and [Tajikistan](/source/Tajikistan); and of [Mogok](/source/Mogok) in [Myanmar](/source/Myanmar). Over the last decades gem quality spinels are found in the marbles of [Lục Yên District](/source/L%E1%BB%A5c_Y%C3%AAn_District) ([Vietnam](/source/Vietnam)), [Mahenge](/source/Mahenge_Mountains) and Matombo ([Tanzania](/source/Tanzania)), Tsavo ([Kenya](/source/Kenya)) and in the gravels of Tunduru ([Tanzania](/source/Tanzania)) and Ilakaka ([Madagascar](/source/Madagascar)).[16][24]

Since 2000, in several locations around the world, spinels have been discovered with unusual vivid pink or blue colors. Such "glowing" spinels are known from Mogok (Myanmar),[25] Mahenge plateau (Tanzania), Lục Yên District (Vietnam)[26] and some more localities. In 2018 bright blue spinels have been reported also in the southern part of [Baffin Island](/source/Baffin_Island) (Canada).[27] The pure blue coloration of spinel is caused by small additions of [cobalt](/source/Cobalt).[28]

## Synthetic spinel

Synthetic spinel can be produced by similar means to synthetic corundum, including the [Verneuil method](/source/Verneuil_method) and the [flux method](/source/Ceramic_flux) pioneered by [Edmond Frémy](/source/Edmond_Fr%C3%A9my). It is widely used as an inexpensive cut gem in [birthstone](/source/Birthstone) [jewelry](/source/Jewelry) for the month of [August](/source/August). Light blue synthetic spinel is a good imitation of aquamarine beryl, and green synthetic spinel is used as an emerald or tourmaline simulant.[29] By 2015, transparent spinel was being made in sheets and other shapes through [sintering](/source/Sintering).[30] Synthetic spinel, which looks like glass but has notably higher strength against pressure, can also have applications in military and commercial use.[31]

Spinel-type chalcogenides are also investigated as optoelectronic semiconductors. In 2025, Hanzawa et al. reported d0-cation spinel sulfides based on ZnSc2S4 and (Zn,Mg)Sc2S4 with color-tunable direct band gaps and ambipolar dopability.[32]

## See also

- [Minerals portal](https://en.wikipedia.org/wiki/Portal:Minerals)

- [Aluminium oxynitride](/source/Aluminium_oxynitride)

- [Ceylonite](/source/Ceylonite)

- [The Three Brothers](/source/The_Three_Brothers_(jewel)), a lost 14th-century crown jewel with three red spinels in a triangular arrangement

## References

1. **[^](#cite_ref-1)** Warr, L.N. (2021). ["IMA–CNMNC approved mineral symbols"](https://doi.org/10.1180%2Fmgm.2021.43). *Mineralogical Magazine*. **85** (3): 291–320. [Bibcode](/source/Bibcode_(identifier)):[2021MinM...85..291W](https://ui.adsabs.harvard.edu/abs/2021MinM...85..291W). [doi](/source/Doi_(identifier)):[10.1180/mgm.2021.43](https://doi.org/10.1180%2Fmgm.2021.43). [S2CID](/source/S2CID_(identifier)) [235729616](https://api.semanticscholar.org/CorpusID:235729616).

1. **[^](#cite_ref-2)** Lancashire, Robert John. ["Normal spinels"](https://web.archive.org/web/20180808174808/http://wwwchem.uwimona.edu.jm/courses/spinel.html). *CHEM2101 (C 21J) Inorganic Chemistry*. Chemistry of transition metal complexes. Kingston, Jamaica: University of the West Indies. Archived from [the original](http://wwwchem.uwimona.edu.jm/courses/spinel.html) on 2018-08-08.

1. **[^](#cite_ref-3)** Grimes, N.W.; et al. (8 April 1983). "New symmetry and structure for spinel". *[Proceedings of the Royal Society of London](/source/Proceedings_of_the_Royal_Society_of_London)*. Series A, Mathematical and Physical Sciences. **386** (1791): 333–345. [Bibcode](/source/Bibcode_(identifier)):[1983RSPSA.386..333G](https://ui.adsabs.harvard.edu/abs/1983RSPSA.386..333G). [doi](/source/Doi_(identifier)):[10.1098/rspa.1983.0039](https://doi.org/10.1098%2Frspa.1983.0039). [JSTOR](/source/JSTOR_(identifier)) [2397417](https://www.jstor.org/stable/2397417). [S2CID](/source/S2CID_(identifier)) [96560029](https://api.semanticscholar.org/CorpusID:96560029).

1. **[^](#cite_ref-4)** Hwang, L.; et al. (July 1973). ["On the space group of MgAl 2O 4 spinel"](https://www.researchgate.net/publication/233373497). *[Philosophical Magazine](/source/Philosophical_Magazine)*. [doi](/source/Doi_(identifier)):[10.1080/14786437308217448](https://doi.org/10.1080%2F14786437308217448).

1. ^ [***a***](#cite_ref-Mindat_5-0) [***b***](#cite_ref-Mindat_5-1) ["Spinel"](https://www.mindat.org/show.php?id=3729). *[mindat.org](/source/Mindat.org)*.

1. **[^](#cite_ref-6)** [*Spinel Mineral Data*](http://webmineral.com/data/Spinel.shtml), WebMineral.com

1. **[^](#cite_ref-7)** "spinel". *The Chambers Dictionary* (9th ed.). Chambers. 2003. [ISBN](/source/ISBN_(identifier)) [0-550-10105-5](https://en.wikipedia.org/wiki/Special:BookSources/0-550-10105-5).

1. **[^](#cite_ref-8)** Nesse, William D. (2000). *Introduction to mineralogy*. New York, NY: Oxford University Press. pp. 362–363. [ISBN](/source/ISBN_(identifier)) [9780195106916](https://en.wikipedia.org/wiki/Special:BookSources/9780195106916).

1. ^ [***a***](#cite_ref-klein-hurlbut_9-0) [***b***](#cite_ref-klein-hurlbut_9-1) Klein, Cornelis; Hurlbut, Cornelius S., Jr. (1993). *Manual of Mineralogy (after James D. Dana)* (21st ed.). New York, NY: Wiley. [ISBN](/source/ISBN_(identifier)) [047157452X](https://en.wikipedia.org/wiki/Special:BookSources/047157452X).{{[cite book](https://en.wikipedia.org/wiki/Template:Cite_book)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. **[^](#cite_ref-10)** ["Minerals colored by metal ions"](http://minerals.gps.caltech.edu/color_causes/Metal_Ion/index.html). *minerals.gps.caltech.edu*. [CalTech](/source/CalTech). Retrieved 2023-03-01.

1. **[^](#cite_ref-Butler1989_11-0)** Sir Thomas Butler (1989). [*The Crown Jewels and Coronation Ceremony*](https://books.google.com/books?id=brbvmKAQ5PEC). Pitkin. p. 6. [ISBN](/source/ISBN_(identifier)) [978-0-85372-467-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-85372-467-4).

1. **[^](#cite_ref-12)** Pardieu, V.; Farkhodova, T. (Summer 2019). ["Spinel from Tajikistan"](https://www.researchgate.net/publication/339439345). *InColor*: 30–33. Retrieved 28 April 2021.

1. **[^](#cite_ref-13)** "Samarian spinel". *Dictionary of Gems and Gemology*: 657–737. 2005. [doi](/source/Doi_(identifier)):[10.1007/3-540-27269-0_19](https://doi.org/10.1007%2F3-540-27269-0_19).

1. **[^](#cite_ref-14)** Lytvynov, L.A. (2011). ["On the words used as names for ruby and sapphire"](http://dspace.nbuv.gov.ua/bitstream/handle/123456789/135445/21-Lytvynov.pdf?sequence=1) (PDF). *Functional Materials*. **18** (2): 275. Retrieved 29 April 2021.

1. **[^](#cite_ref-15)** Hughes, R.W. (1994). ["The rubies and spinels of Afghanistan: A brief history"](https://gem-a.com/images/Documents/JoG/Archive/1956-97/JoG1994_24_4.pdf#page=26) (PDF). *Journal of Gemmology*. **24** (4): 256–267. [doi](/source/Doi_(identifier)):[10.15506/JoG.1994.24.4.256](https://doi.org/10.15506%2FJoG.1994.24.4.256). Retrieved 29 April 2021.

1. ^ [***a***](#cite_ref-FOOTNOTEPardieuFarkhodova2019_16-0) [***b***](#cite_ref-FOOTNOTEPardieuFarkhodova2019_16-1) [***c***](#cite_ref-FOOTNOTEPardieuFarkhodova2019_16-2) [Pardieu & Farkhodova 2019](#CITEREFPardieuFarkhodova2019).

1. **[^](#cite_ref-17)** Biswas, A.K. (2001). "Minerals and their Exploitation in Ancient and Pre-modern India". In Ramachandra Rao, P.; Goswami, N.G. (eds.). *Metallurgy in India : a retrospective*. New Delhi: India International Publisher. pp. 1–22. [ASIN](/source/ASIN_(identifier)) [B002A9M6QU](https://www.amazon.com/dp/B002A9M6QU).

1. **[^](#cite_ref-18)** Irvine TN (1977). "Origin of chromite layers in the Muskox intrusion and other stratiform intrusions: a new perspective". *Geology*. **5** (5): 273. [doi](/source/Doi_(identifier)):[10.1130/0091-7613(1977)5<273:ooclit>2.0.co;2](https://doi.org/10.1130%2F0091-7613%281977%295%3C273%3Aooclit%3E2.0.co%3B2).

1. **[^](#cite_ref-19)** Leuthold J, Blundy JD, Brooker RA (2015). ["Experimental petrology constraints on the recycling of mafic cumulate: A focus on Cr-spinel from the Rum Eastern Layered Intrusion, Scotland"](https://research-information.bristol.ac.uk/en/publications/experimental-petrology-constraints-on-the-recycling-of-mafic-cumulate(43578f76-07c8-4676-84d1-d763d5228efb).html). *Contributions to Mineralogy and Petrology*. **170** (2): 12. [Bibcode](/source/Bibcode_(identifier)):[2015CoMP..170...12L](https://ui.adsabs.harvard.edu/abs/2015CoMP..170...12L). [doi](/source/Doi_(identifier)):[10.1007/s00410-015-1165-0](https://doi.org/10.1007%2Fs00410-015-1165-0). [hdl](/source/Hdl_(identifier)):[1983/43578f76-07c8-4676-84d1-d763d5228efb](https://hdl.handle.net/1983%2F43578f76-07c8-4676-84d1-d763d5228efb). [S2CID](/source/S2CID_(identifier)) [129562202](https://api.semanticscholar.org/CorpusID:129562202).

1. **[^](#cite_ref-20)** O Driscoll B, Emeleus CH, Donaldson CH, Daly JS (2009). "The roles of melt infiltration and cumulate assimilation in the formation of anorthosite and a Cr-spinel seam in the Rum Eastern Layered Intrusion, NW Scotland". *Lithos*. **111** (1–2): 6–20. [Bibcode](/source/Bibcode_(identifier)):[2009Litho.111....6O](https://ui.adsabs.harvard.edu/abs/2009Litho.111....6O). [doi](/source/Doi_(identifier)):[10.1016/j.lithos.2008.11.011](https://doi.org/10.1016%2Fj.lithos.2008.11.011).

1. **[^](#cite_ref-21)** Klemme, Stephan (2004). ["The influence of Cr on the garnet–spinel transition in the Earth's mantle: Experiments in the system MgO—Cr2O3—SiO2 and thermodynamic modelling"](http://www.eeo.ed.ac.uk/homes/sklemme/publications/Klemme_Lithos_2004.pdf) (PDF). *Lithos*. **77** (1–4): 639–646. [Bibcode](/source/Bibcode_(identifier)):[2004Litho..77..639K](https://ui.adsabs.harvard.edu/abs/2004Litho..77..639K). [doi](/source/Doi_(identifier)):[10.1016/j.lithos.2004.03.017](https://doi.org/10.1016%2Fj.lithos.2004.03.017).

1. **[^](#cite_ref-22)** Philpotts, Anthony R.; Ague, Jay J. (2009). *Principles of igneous and metamorphic petrology* (2nd ed.). Cambridge, UK: Cambridge University Press. p. 17. [ISBN](/source/ISBN_(identifier)) [9780521880060](https://en.wikipedia.org/wiki/Special:BookSources/9780521880060).

1. **[^](#cite_ref-23)** MacPherson, G.J. (2007). "Calcium–Aluminum-Rich Inclusions in Chondritic Meteorites". *Treatise on Geochemistry*: 1–47. [doi](/source/Doi_(identifier)):[10.1016/B0-08-043751-6/01065-3](https://doi.org/10.1016%2FB0-08-043751-6%2F01065-3). [ISBN](/source/ISBN_(identifier)) [9780080437514](https://en.wikipedia.org/wiki/Special:BookSources/9780080437514).

1. **[^](#cite_ref-24)** Pardieu, Vincent; Hughes, R. W.; Boehm, E. (2008). ["Spinel: Resurrection of a classic"](https://www.researchgate.net/publication/264973257). *InColor Magazine*: 10–18. Retrieved 29 April 2021.

1. **[^](#cite_ref-25)** Pardieu, Vincent (2014). ["Hunting for "Jedi" Spinels in Mogok"](https://www.gia.edu/gems-gemology/spring-2014-pardieu-jedi-spinels-in-mogok/). *Gems & Gemology*. **50** (1): 46–57. [doi](/source/Doi_(identifier)):[10.5741/GEMS.50.1.46](https://doi.org/10.5741%2FGEMS.50.1.46).

1. **[^](#cite_ref-26)** Wondermondo (16 June 2019). ["Finds of cobalt blue spinel in Lục Yên, Vietnam"](https://www.wondermondo.com/blue-spinel-in-luc-yen/).

1. **[^](#cite_ref-27)** Mining.Com (5 April 2019). ["Scientists figure out origin of cobalt-blue spinel in Canada's Arctic"](https://www.mining.com/scientists-figure-origin-cobalt-blue-spinel-canadas-arctic/).

1. **[^](#cite_ref-28)** Boris Chauviré, Benjamin Rondeau, Emmanuel Fritsch, Phillipe Ressigeac, and Jean-Luc Devidal (Spring 2015). ["Blue Spinel From the Luc Yen District of Vietnam"](https://www.researchgate.net/publication/276519619). *Gems & Gemology*.{{[cite journal](https://en.wikipedia.org/wiki/Template:Cite_journal)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. **[^](#cite_ref-29)** Simon & Schuster's Guide to Gems and Precious Stones, K. Lyman, 1996

1. **[^](#cite_ref-30)** ["Researchers finding applications for tough spinel ceramic"](http://phys.org/news/2015-04-applications-tough-spinel-ceramic.html). *Phys.org*. 24 April 2015.

1. **[^](#cite_ref-31)** ["Transparent Armor from NRL; Spinel Could Also Ruggedize Your Smart Phone"](https://www.nrl.navy.mil/Media/News/Article/2534832/transparent-armor-from-nrl-spinel-could-also-ruggedize-your-smart-phone/). Naval Research Laboratory. 23 April 2015. [Archived](https://web.archive.org/web/20230804234329/https://www.nrl.navy.mil/Media/News/Article/2534832/transparent-armor-from-nrl-spinel-could-also-ruggedize-your-smart-phone/) from the original on 4 August 2023. Retrieved 4 August 2023.

1. **[^](#cite_ref-32)** Hanzawa, Kota; Nagai, Takayuki; Nagasawa, Ryoga; Katase, Takayoshi; Hosono, Hideo; Hiramatsu, Hidenori (1 October 2025). "d0 Cation-Based Spinel-Type Sulfide Semiconductors with Color-Tunable Direct-Gap and Ambipolar Dopability". *Journal of the American Chemical Society*. **147** (39): 35935–35941. [doi](/source/Doi_(identifier)):[10.1021/jacs.5c12816](https://doi.org/10.1021%2Fjacs.5c12816).

## Bibliography

- Deer, Howie and Zussman (1966). *[An Introduction to the Rock-Forming Minerals](/source/An_Introduction_to_the_Rock-Forming_Minerals)*, Longman, pp. 424–433, [ISBN](/source/ISBN_(identifier)) [0-582-44210-9](https://en.wikipedia.org/wiki/Special:BookSources/0-582-44210-9).

- Shumann, Walter (2006). *Gemstones of the World* 3rd edition, Sterling, pp. 116–117.

## External links

Wikimedia Commons has media related to [Spinel](https://commons.wikimedia.org/wiki/Category:Spinel).

- [Spinel structure](http://www.uwgb.edu/dutchs/PETROLOGY/Spinel%20Structure.HTM) at the [University of Wisconsin - Green Bay](/source/University_of_Wisconsin_-_Green_Bay)

- [Spinel structure](http://www.tf.uni-kiel.de/matwis/amat/def_en/kap_2/basics/b2_1_6.html) at the Institut for materials science of the [University of Kiel](/source/University_of_Kiel)

- [Value of Spinel](http://www.gemsociety.org/article/spinel-jewelry-and-gemstone-information/)

v t e Minerals Overview Mineral List Mineralogy History Common minerals Amphibole Bridgmanite K-feldspar Mica Olivine Plagioclase Pyroxene Quartz Spinel Related Industrial mineral Minerals portal

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