Reidite is a rare polymorph of ZrSiO4 created when zircon experiences high pressure and temperature. Reidite is denser than zircon and has the same crystal structure as scheelite. All natural occurrences of reidite are associated with meteorite impact events.

CategoryZircon group
(repeating unit)
IMA symbolRei[1]
Strunz classification9.AD.45
Crystal systemTetragonal
Crystal classDipyramidal (4/m)
H-M symbol: (4/m)
Space groupI41/a
Unit cella = 4.738, c = 10.506 [Å], Z = 4
Formula mass183.31 g/mol
ColorColorless to white
Crystal habitEpitaxial - crystallographic alignment with a precursor mineral, occurs as inclusions in other minerals.
Mohs scale hardness7.5
Specific gravity5.16
Optical propertiesUniaxial (+)
Refractive indexnω=1.64, nε=1.655

On Earth, reidite has been reported from ten impact structures: the Chesapeake Bay Crater in Virginia; Ries Crater in Germany; Xiuyan Crater in China; Woodleigh Crater in Western Australia;[4] Rock Elm Crater in Wisconsin;[5] Dhala Crater in India;[6] Stac Fada in Scotland; Haughton in Canada; Steen River in Canada, and Rochechouart in France. Reidite has also been found in one lunar meteorite.[7]

Name origin and discovery


Reidite is named after Alan F. Reid, the scientist who first synthesized it during high-pressure experiments in the laboratory in 1969.[8]

Reidite was first discovered in natural samples by B.P. Glass and Shaobin Liu in 2001.[9]



Reidite is formed from zircon above ~30GPa in shock recovery experiments. However, the temperatures generated during meteorite impacts are much higher, and reidite can be formed down to ~9GPa under natural impact conditions.[10] Reidite has been found in lamellar, granular, and dendritic forms within host zircon, typically making up less than 10% of the grain. Reidite from Rochechouart impact structure has also been reported as bladed, wedged, and massive.[11]

Libyan desert glass may show lattice deformation in zircon that is interpreted as evidence of this material having previously contained reidite, and as such constitutes strong evidence for its impact origin.[12]

Relationship of Reidite to Other Specimens
9.AD.25 Uvarovite Ca3Cr2(SiO4)3
9.AD.25 Wadalite (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3
9.AD.25 Holtstamite Ca3(Al,Mn3+)2(SiO4)2(OH)4
9.AD.25 Kerimasite Ca3Zr2(SiO4)(Fe3+O4)2
9.AD.25 Toturite Ca3Sn2(SiO4)(Fe3+O4)2
9.AD.25 Momoiite (Mn2+,Ca)3V23+(SiO4)3
9.AD.25 Eltyubyuite Ca12Fe103+Si4O32Cl6
9.AD.25 Hutcheonite Ca3Ti2(SiAl2)O12
9.AD.30 Coffinite (U4+,Th)(SiO4)1-x(OH)4x
9.AD.30 Hafnon HfSiO4
9.AD.30 Thorite (Th,U)SiO4
9.AD.30 Zircon ZrSiO4
9.AD.30 Stetindite Ce4+SiO4
9.AD.35 Huttonite ThSiO4
9.AD.35 Tombarthite-(Y) Y4(Si,H4)4O12−x(OH)4+2x
9.AD.40 Eulytine Bi4(SiO4)3

See also



  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Reidite". Hudson Institute of Mineralogy. Retrieved 18 March 2015.
  3. ^ "Reidite Mineral Data". Retrieved 18 March 2015.
  4. ^ Discovery of reidite, one of the rarest minerals on Earth, may reveal Australia's biggest crater ABC News, 16 October 2018. Retrieved 17 October 2018.
  5. ^ Oskin, Becky (3 November 2014). "Rare Mineral Discovered in Ancient Meteorite Impact Crater". Livescience. Retrieved 24 March 2015.
  6. ^ Li, Shan-Shan; Keerthy, S.; Santosh, M.; Singh, S.P.; Deering, C.D.; Satyanarayanan, M.; Praveen, M.N.; Aneeshkumar, V.; Indu, G.K. (February 2018). "Anatomy of impactites and shocked zircon grains from Dhala reveals Paleoproterozoic meteorite impact in the Archean basement rocks of Central India". Gondwana Research. 54: 81–101. Bibcode:2018GondR..54...81L. doi:10.1016/
  7. ^ Xing, Weifan; Lin, Yangting; Zhang, Chi; Zhang, Mingming; Hu, Sen; Hofmann, Beda A.; Sekine, Toshimori; Xiao, Long; Gu, Lixin (2020-11-16). "Discovery of Reidite in the Lunar Meteorite Sayh al Uhaymir 169". Geophysical Research Letters. 47 (21). Bibcode:2020GeoRL..4789583X. doi:10.1029/2020GL089583. ISSN 0094-8276. S2CID 226337486.
  8. ^ Reid, A. F.; Ringwood, A. E. (1969-06-01). "Newly observed high pressure transformations in Mn3O4, CaAl2O4, and ZrSiO4". Earth and Planetary Science Letters. 6 (3): 205–208. doi:10.1016/0012-821X(69)90091-0. ISSN 0012-821X.
  9. ^ Glass, B.P.; Liu, Shaobin (2001-04-01). "Discovery of high-pressure ZrSiO4 polymorph in naturally occurring shock-metamorphosed zircons". Geology. 29 (4): 371–373. doi:10.1130/0091-7613(2001)029<0371:DOHPZP>2.0.CO;2. ISSN 0091-7613.
  10. ^ Timms, Nicholas E.; Erickson, Timmons M.; Pearce, Mark A.; Cavosie, Aaron J.; Schmieder, Martin; Tohver, Eric; Reddy, Steven M.; Zanetti, Michael R.; Nemchin, Alexander A.; Wittmann, Axel (2017-02-01). "A pressure-temperature phase diagram for zircon at extreme conditions". Earth-Science Reviews. 165: 185–202. Bibcode:2017ESRv..165..185T. doi:10.1016/j.earscirev.2016.12.008. ISSN 0012-8252.
  11. ^ Plan, Anders; Kenny, Gavin G.; Erickson, Timmons M.; Lindgren, Paula; Alwmark, Carl; Holm-Alwmark, Sanna; Lambert, Philippe; Scherstén, Anders; Söderlund, Ulf; Osinski, Gordon (October 2021). "Exceptional preservation of reidite in the Rochechouart impact structure, France: New insights into shock deformation and phase transition of zircon". Meteoritics & Planetary Science. 56 (10): 1795–1828. Bibcode:2021M&PS...56.1795P. doi:10.1111/maps.13723. ISSN 1086-9379. S2CID 238711754.
  12. ^ Cavosie, Aaron J. (22 May 2019). "How we solved the mystery of Libyan desert glass". The Conversation. Retrieved 2019-10-12.
  • List of Minerals