fbpx
Wikipedia

Spinel

January 07, 2023

For the larger class of minerals, see Spinel group. For the Russian painter, see Joseph Spinel. For the Steven Universe character, see Spinel (Steven Universe).

Spinel (/spɪˈnɛl, ˈspɪnəl/[6]) is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl
2O
4 in the cubic crystal system. Its name comes from the Latin word spinella, which means spine in reference to its pointed crystals.[4]

Spinel
Small spinel crystal on top of a white calcite from Mogok, Myanmar, measuring 1.5 × 1.1 × 1 cm in size
General
Category
Formula
(repeating unit)		MgAl
2O
4
Strunz classification4.BB.05
Crystal systemCubic
Crystal classHextetrahedral (43m)
H–M symbol: (43m)[1][2][3]
Space groupF 4 3 m (No. 216)
Unit cella = 8.0898(9) Å; Z = 8
Identification
ColorVarious; red, pink, blue, lavender/violet, dark green, brown, black, colourless
Crystal habitOctahedral or flat triangular plates caused by twinning
Twinningcommon
CleavageNone
FractureConchoidal
Mohs scale hardness7.5–8.0
LusterVitreous
StreakWhite
DiaphaneityTransparent 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 propertiesIsotropic
Refractive index1.719
PleochroismAbsent
SolubilityNone
Other characteristicsWeak to medium magnetic, sometimes fluorescent (red synthetic yes, natural red sometimes)
References[4][5]
Polyhedral representation of spinel MgAl2O4

Properties

 
Cut spinel

Spinel crystallizes in the isometric system; common crystal forms are octahedra, usually twinned. It has no true cleavage, but shows an octahedral parting and a conchoidal fracture.[7] Its hardness is 8, its specific gravity is 3.5–4.1, and it is transparent to opaque with a vitreous to dull luster. It may be colorless, but is usually various shades of red, lavender, blue, green, brown, black, or yellow.[8] Some spinels are among the most famous gemstones; among them are the Black Prince's Ruby and the "Timur ruby" in the British Crown Jewels,[9] and the "Côte de Bretagne", formerly from the French Crown jewels.[10] The Samarian Spinel is the largest known spinel in the world, weighing 500 carats (100 g).[11]

The transparent red spinels were called spinel-rubies[12] or balas rubies.[13] In the past, before the arrival of modern science, spinels and rubies were equally known as rubies. After the 18th century, the word ruby was only used for the red gem variety of the mineral corundum, and the word spinel came to be used.[14] "Balas" is derived from Balascia, the ancient name for Badakhshan, a region in central Asia situated in the upper valley of the Panj River, one of the principal tributaries of the Oxus River. However, "Balascia" itself may be derived from Sanskrit bālasūryaka, which translates as "crimson-coloured morning sun".[15] Mines in the Gorno Badakhshan region of Tajikistan constituted for centuries the main source for red and pink spinels.[14]

Occurrence

Geologic occurrence

Spinel is found as a metamorphic mineral in metamorphosed limestones and silica-poor mudstones.[8] It also occurs as a primary mineral in rare mafic igneous rocks; in these igneous rocks, the magmas are relatively deficient in alkalis relative to aluminium, and aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel. This is why spinel and 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 [16] or rock (e.g. gabbro, troctolite).[17][18]

Spinel, (Mg,Fe)(Al,Cr)2O4, is common in peridotite in the uppermost Earth's mantle, between approximately 20 km to approximately 120 km, possibly to lower depths depending on the chromium content.[19] At significantly shallower depths, above the Moho, calcic plagioclase is the more stable aluminous mineral in peridotite while garnet is the stable phase deeper in the mantle below the spinel stability region.[20]

Spinel, (Mg,Fe)Al2O4, is a common mineral in the Ca-Al-rich inclusions (CAIs) in some chondritic meteorites.[21]

Geographical occurrence

Spinel has long been found in the gemstone-bearing gravel of Sri Lanka and in limestones of the Badakshan Province in modern-day Afghanistan and Tajikistan; and of Mogok in Myanmar. Over the last decades gem quality spinels are found in the marbles of Lục Yên District (Vietnam), Mahenge and Matombo (Tanzania), Tsavo (Kenya) and in the gravels of Tunduru (Tanzania) and Ilakaka (Madagascar).[14][22]

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),[23] Mahenge plateau (Tanzania), Lục Yên District (Vietnam)[24] and some more localities. In 2018 bright blue spinels have been reported also in the southern part of Baffin Island (Canada).[25] The pure blue coloration of spinel is caused by small additions of cobalt.[26]

Synthetic spinel

Synthetic spinel can be produced by similar means to synthetic corundum, including the Verneuil method and the flux method pioneered by Edmond Frémy. It is widely used as an inexpensive cut gem in birthstone jewelry for the month of August. Light blue synthetic spinel is a good imitation of aquamarine beryl, and green synthetic spinel is used as an emerald or tourmaline simulant.[27] By 2015, transparent spinel was being made in sheets and other shapes through sintering.[28] Synthetic spinel, which looks like glass but has notably higher strength against pressure, can also have applications in military and commercial use.[29]

See also

References

  1. ^ Robert John Lancashire. . CHEM2101 (C 21J) Inorganic Chemistry – Chemistry of Transition Metal Complexes. University of the West Indies. Archived from the original on 2018-08-08.
  2. ^ N. W. Grimes; et al. (Apr 8, 1983). "New Symmetry and Structure for Spinel". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. 386 (1791): 333–345. Bibcode:1983RSPSA.386..333G. doi:10.1098/rspa.1983.0039. JSTOR 2397417. S2CID 96560029.
  3. ^ L. Hwang; et al. (Jul 1973). "On the space group of MgAl
    2    O
    4     spinel". Philosophical Magazine. doi:10.1080/14786437308217448.
  4. ^ a b Spinel, Mindat.org
  5. ^ Spinel Mineral Data, WebMineral.com
  6. ^ "spinel". The Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.
  7. ^ Nesse, William D. (2000). Introduction to mineralogy. New York: Oxford University Press. pp. 362–363. ISBN 9780195106916.
  8. ^ a b Klein, Cornelis; Hurlbut, Cornelius S. Jr. (1993). Manual of mineralogy : (after James D. Dana) (21st ed.). New York: Wiley. ISBN 047157452X.
  9. ^ Sir Thomas Butler (1989). The Crown Jewels and Coronation Ceremony. Pitkin. p. 6. ISBN 978-0-85372-467-4.
  10. ^ Pardieu, V.; Farkhodova, T. (Summer 2019). "Spinel from Tajikistan". InColor: 30–33. Retrieved 28 April 2021.
  11. ^ "Samarian spinel". Dictionary of Gems and Gemology: 657–737. 2005. doi:10.1007/3-540-27269-0_19.
  12. ^ Lytvynov, L.A. (2011). "On the words used as names for ruby and sapphire" (PDF). Functional Materials. 18 (2): 275. Retrieved 29 April 2021.
  13. ^ Hughes, R.W. (1994). "The rubies and spinels of Afghanistan: A brief history" (PDF). Journal of Gemmology. 24 (4): 256–267. doi:10.15506/JoG.1994.24.4.256. Retrieved 29 April 2021.
  14. ^ a b c Pardieu & Farkhodova 2019.
  15. ^ 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 B002A9M6QU.
  16. ^ Irvine TN (1977). "Origin of chromite layers in the Muskox intrusion and other stratiform intrusions: a new perspective". Geology. 5 (5): 273. doi:10.1130/0091-7613(1977)5<273:ooclit>2.0.co;2.
  17. ^ 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". Contributions to Mineralogy and Petrology. 170 (2): 12. Bibcode:2015CoMP..170...12L. doi:10.1007/s00410-015-1165-0. hdl:1983/43578f76-07c8-4676-84d1-d763d5228efb. S2CID 129562202.
  18. ^ 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:2009Litho.111....6O. doi:10.1016/j.lithos.2008.11.011.
  19. ^ 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" (PDF). Lithos. 77 (1–4): 639–646. Bibcode:2004Litho..77..639K. doi:10.1016/j.lithos.2004.03.017.
  20. ^ Philpotts, Anthony R.; Ague, Jay J. (2009). Principles of igneous and metamorphic petrology (2nd ed.). Cambridge, UK: Cambridge University Press. p. 17. ISBN 9780521880060.
  21. ^ MacPherson, G.J. (2007). "Calcium–Aluminum-Rich Inclusions in Chondritic Meteorites". Treatise on Geochemistry: 1–47. doi:10.1016/B0-08-043751-6/01065-3. ISBN 9780080437514.
  22. ^ Pardieu, Vincent; Hughes, R. W.; Boehm, E. (2008). "Spinel: Resurrection of a classic". InColor Magazine: 10–18. Retrieved 29 April 2021.
  23. ^ Pardieu, Vincent (2014). "Hunting for "Jedi" Spinels in Mogok". Gems & Gemology. 50 (1): 46–57. doi:10.5741/GEMS.50.1.46.
  24. ^ Wondermondo (16 June 2019). "Finds of cobalt blue spinel in Lục Yên, Vietnam".
  25. ^ Mining.Com (5 April 2019). "Scientists figure out origin of cobalt-blue spinel in Canada's Arctic".
  26. ^ Boris Chauviré, Benjamin Rondeau, Emmanuel Fritsch, Phillipe Ressigeac, and Jean-Luc Devidal (Spring 2015). "Blue Spinel From the Luc Yen District of Vientam". Gems & Gemology.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  27. ^ Simon & Schuster's Guide to Gems and Precious Stones, K. Lyman, 1996
  28. ^ "Researchers finding applications for tough spinel ceramic". Phys.org. 24 April 2015.
  29. ^ "Transparent Armor from NRL; Spinel Could Also Ruggedize Your Smart Phone". Naval Research Laboratory. 23 April 2015.

Bibliography

External links

 
Wikimedia Commons has media related to Spinel.

January 07, 2023
spinel, larger, class, minerals, group, russian, painter, joseph, steven, universe, character, steven, universe, magnesium, aluminium, member, larger, spinel, group, minerals, formula, mgal2, cubic, crystal, system, name, comes, from, latin, word, spinella, wh. For the larger class of minerals see Spinel group For the Russian painter see Joseph Spinel For the Steven Universe character see Spinel Steven Universe Spinel s p ɪ ˈ n ɛ l ˈ s p ɪ n el 6 is the magnesium aluminium member of the larger spinel group of minerals It has the formula MgAl2 O4 in the cubic crystal system Its name comes from the Latin word spinella which means spine in reference to its pointed crystals 4 SpinelSmall spinel crystal on top of a white calcite from Mogok Myanmar measuring 1 5 1 1 1 cm in sizeGeneralCategoryOxide minerals Spinel group Spinel structural groupFormula repeating unit MgAl2 O4Strunz classification4 BB 05Crystal systemCubicCrystal classHextetrahedral 4 3m H M symbol 4 3m 1 2 3 Space groupF 4 3 m No 216 Unit cella 8 0898 9 A Z 8IdentificationColorVarious red pink blue lavender violet dark green brown black colourlessCrystal habitOctahedral or flat triangular plates caused by twinningTwinningcommonCleavageNoneFractureConchoidalMohs scale hardness7 5 8 0LusterVitreousStreakWhiteDiaphaneityTransparent to opaqueSpecific 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 propertiesIsotropicRefractive index1 719PleochroismAbsentSolubilityNoneOther characteristicsWeak to medium magnetic sometimes fluorescent red synthetic yes natural red sometimes References 4 5 Polyhedral representation of spinel MgAl2O4 Contents 1 Properties 2 Occurrence 2 1 Geologic occurrence 2 2 Geographical occurrence 3 Synthetic spinel 4 See also 5 References 6 Bibliography 7 External linksProperties Edit Cut spinel Spinel crystallizes in the isometric system common crystal forms are octahedra usually twinned It has no true cleavage but shows an octahedral parting and a conchoidal fracture 7 Its hardness is 8 its specific gravity is 3 5 4 1 and it is transparent to opaque with a vitreous to dull luster It may be colorless but is usually various shades of red lavender blue green brown black or yellow 8 Some spinels are among the most famous gemstones among them are the Black Prince s Ruby and the Timur ruby in the British Crown Jewels 9 and the Cote de Bretagne formerly from the French Crown jewels 10 The Samarian Spinel is the largest known spinel in the world weighing 500 carats 100 g 11 The transparent red spinels were called spinel rubies 12 or balas rubies 13 In the past before the arrival of modern science spinels and rubies were equally known as rubies After the 18th century the word ruby was only used for the red gem variety of the mineral corundum and the word spinel came to be used 14 Balas is derived from Balascia the ancient name for Badakhshan a region in central Asia situated in the upper valley of the Panj River one of the principal tributaries of the Oxus River However Balascia itself may be derived from Sanskrit balasuryaka which translates as crimson coloured morning sun 15 Mines in the Gorno Badakhshan region of Tajikistan constituted for centuries the main source for red and pink spinels 14 Occurrence EditGeologic occurrence Edit Spinel is found as a metamorphic mineral in metamorphosed limestones and silica poor mudstones 8 It also occurs as a primary mineral in rare mafic igneous rocks in these igneous rocks the magmas are relatively deficient in alkalis relative to aluminium and aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel This is why spinel and 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 16 or rock e g gabbro troctolite 17 18 Spinel Mg Fe Al Cr 2O4 is common in peridotite in the uppermost Earth s mantle between approximately 20 km to approximately 120 km possibly to lower depths depending on the chromium content 19 At significantly shallower depths above the Moho calcic plagioclase is the more stable aluminous mineral in peridotite while garnet is the stable phase deeper in the mantle below the spinel stability region 20 Spinel Mg Fe Al2O4 is a common mineral in the Ca Al rich inclusions CAIs in some chondritic meteorites 21 Geographical occurrence Edit Spinel has long been found in the gemstone bearing gravel of Sri Lanka and in limestones of the Badakshan Province in modern day Afghanistan and Tajikistan and of Mogok in Myanmar Over the last decades gem quality spinels are found in the marbles of Lục Yen District Vietnam Mahenge and Matombo Tanzania Tsavo Kenya and in the gravels of Tunduru Tanzania and Ilakaka Madagascar 14 22 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 23 Mahenge plateau Tanzania Lục Yen District Vietnam 24 and some more localities In 2018 bright blue spinels have been reported also in the southern part of Baffin Island Canada 25 The pure blue coloration of spinel is caused by small additions of cobalt 26 Synthetic spinel EditSynthetic spinel can be produced by similar means to synthetic corundum including the Verneuil method and the flux method pioneered by Edmond Fremy It is widely used as an inexpensive cut gem in birthstone jewelry for the month of August Light blue synthetic spinel is a good imitation of aquamarine beryl and green synthetic spinel is used as an emerald or tourmaline simulant 27 By 2015 transparent spinel was being made in sheets and other shapes through sintering 28 Synthetic spinel which looks like glass but has notably higher strength against pressure can also have applications in military and commercial use 29 See also Edit Minerals portal Aluminium oxynitride Ceylonite The Three Brothers a lost 14th century crown jewel with three red spinels in a triangular arrangementReferences Edit Robert John Lancashire Normal Spinels CHEM2101 C 21J Inorganic Chemistry Chemistry of Transition Metal Complexes University of the West Indies Archived from the original on 2018 08 08 N W Grimes et al Apr 8 1983 New Symmetry and Structure for Spinel Proceedings of the Royal Society of London Series A Mathematical and Physical Sciences 386 1791 333 345 Bibcode 1983RSPSA 386 333G doi 10 1098 rspa 1983 0039 JSTOR 2397417 S2CID 96560029 L Hwang et al Jul 1973 On the space group of MgAl2 O4 spinel Philosophical Magazine doi 10 1080 14786437308217448 a b Spinel Mindat org Spinel Mineral Data WebMineral com spinel The Chambers Dictionary 9th ed Chambers 2003 ISBN 0 550 10105 5 Nesse William D 2000 Introduction to mineralogy New York Oxford University Press pp 362 363 ISBN 9780195106916 a b Klein Cornelis Hurlbut Cornelius S Jr 1993 Manual of mineralogy after James D Dana 21st ed New York Wiley ISBN 047157452X Sir Thomas Butler 1989 The Crown Jewels and Coronation Ceremony Pitkin p 6 ISBN 978 0 85372 467 4 Pardieu V Farkhodova T Summer 2019 Spinel from Tajikistan InColor 30 33 Retrieved 28 April 2021 Samarian spinel Dictionary of Gems and Gemology 657 737 2005 doi 10 1007 3 540 27269 0 19 Lytvynov L A 2011 On the words used as names for ruby and sapphire PDF Functional Materials 18 2 275 Retrieved 29 April 2021 Hughes R W 1994 The rubies and spinels of Afghanistan A brief history PDF Journal of Gemmology 24 4 256 267 doi 10 15506 JoG 1994 24 4 256 Retrieved 29 April 2021 a b c Pardieu amp Farkhodova 2019 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 B002A9M6QU Irvine TN 1977 Origin of chromite layers in the Muskox intrusion and other stratiform intrusions a new perspective Geology 5 5 273 doi 10 1130 0091 7613 1977 5 lt 273 ooclit gt 2 0 co 2 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 Contributions to Mineralogy and Petrology 170 2 12 Bibcode 2015CoMP 170 12L doi 10 1007 s00410 015 1165 0 hdl 1983 43578f76 07c8 4676 84d1 d763d5228efb S2CID 129562202 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 2009Litho 111 6O doi 10 1016 j lithos 2008 11 011 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 PDF Lithos 77 1 4 639 646 Bibcode 2004Litho 77 639K doi 10 1016 j lithos 2004 03 017 Philpotts Anthony R Ague Jay J 2009 Principles of igneous and metamorphic petrology 2nd ed Cambridge UK Cambridge University Press p 17 ISBN 9780521880060 MacPherson G J 2007 Calcium Aluminum Rich Inclusions in Chondritic Meteorites Treatise on Geochemistry 1 47 doi 10 1016 B0 08 043751 6 01065 3 ISBN 9780080437514 Pardieu Vincent Hughes R W Boehm E 2008 Spinel Resurrection of a classic InColor Magazine 10 18 Retrieved 29 April 2021 Pardieu Vincent 2014 Hunting for Jedi Spinels in Mogok Gems amp Gemology 50 1 46 57 doi 10 5741 GEMS 50 1 46 Wondermondo 16 June 2019 Finds of cobalt blue spinel in Lục Yen Vietnam Mining Com 5 April 2019 Scientists figure out origin of cobalt blue spinel in Canada s Arctic Boris Chauvire Benjamin Rondeau Emmanuel Fritsch Phillipe Ressigeac and Jean Luc Devidal Spring 2015 Blue Spinel From the Luc Yen District of Vientam Gems amp Gemology a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Simon amp Schuster s Guide to Gems and Precious Stones K Lyman 1996 Researchers finding applications for tough spinel ceramic Phys org 24 April 2015 Transparent Armor from NRL Spinel Could Also Ruggedize Your Smart Phone Naval Research Laboratory 23 April 2015 Bibliography EditDeer Howie and Zussman 1966 An Introduction to the Rock Forming Minerals Longman pp 424 433 ISBN 0 582 44210 9 Shumann Walter 2006 Gemstones of the World 3rd edition Sterling pp 116 117 External links Edit Wikimedia Commons has media related to Spinel Spinel structure at the University of Wisconsin Green Bay Spinel structure at the Institut for materials science of the University of Kiel Value of Spinel Retrieved from https en wikipedia org w index php title Spinel amp oldid 1126203863, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.