Olivine polymorphs
Spinel-type Mg2SiO4
Mineral name: ringwoodite (named after Alfred Edward Ringwood)
Discovery: Tenham meteorite (L6)
Ringwoodite with stacking faults in a shock-induced melt vein of the Tenham chondirite (L6).
Ringwoodite (Rgt) formed in olivine (Ol) grain adjacent to a shock-melt vein of Yamato 791384 (L6). Ringwoodite is like lamella. (Courtesy of M. Miyahara, Hiroshima Univ.)
＊References＊
Ringwood A. E. and Major A. 1966. Earth and Planetary Science Letters 1:241–245. (First synthesis)
Binns R. A., Davis R. J., and Reed,S. J. B. 1969. Nature 221:943–944. (Discovery, description as a new mineral species)
Suito K. 1972. Journal of Physics of the Earth 20:225–243. (First synthesis as pure Mg2SiO4-spinel)
Sasaki S. and Prewitt C. 1982. Journal of Geophysical Research 87:7829–7832. (X-ray structural refinement of synthetic single crystal)
Sazonova, L. V., Fel’dman, V. I., Kozlov E. A., Dubrovinskaya N. A., and Dubrovinskii L. S. 2006. Geochemical International 44:137–142. (First shock-wave synthesis)
Pearson D. G., Brenker F. E., Nestola F., McNeill J., Nasdala L., Hutchison M. T, Matveev K.,Mather G., Silversmit G., Schmitz S., Vekemans B., and Vincze L. 2014. Nature 507:221–224. (Discovery of hydrous ringwoodite as an inclusion in diamond)
Purevjav N., Okuchi T., Wang X., Hoffmann C., and Tomioka N. 2018. Acta Crystallographica B74:115–120. (Determination of hydrogen sites by single-crystal neutron diffraction)
Spinelloid-type Mg2SiO4 [phase III (β)]
Mineral name: wadsleyite (named after Arthur David Wadsley)
Discovery: Tenham meteorite (L6)
Wadsleyite nucleated from the heavily faulted ringwoodite which surrounds it in the Peace River chondrite. (Courtesy of A. Putnis, Univ. of Münster)
Transmission electron micrograph of coexisting wadsleyite (Wd) and ringwoodite (Rw) in the Peace River L6 chondrite (Miyahara et al., 2008). (Courtesy of M. Miyahara, Hiroshima Univ.)
＊References＊
Ringwood A. E. and Major A. 1966. Earth and Planetary Science Letters 1:241–245. (First synthesis)
Putnis A. and Price G. D. 1979. Nature 280:217–218. (Discovery)
Horiuchi H. and Sawamoto H. 1981. American Mineralogist 66:568–575. (X-ray structural refinement of synthetic single crystal)
Price G. D., Putnis A., Agrell S. O., and Smith D. G. W. 1983. Canadian Mineralogist 21:29–53. (Description as a new mineral species)
Tschauner O., Asimow P. D., Kostandova N., Ahrens T. J., Ma C., Sinogeikin S., Liu Z., Fakra S., and Tamura N. 2009. Proceedings of the National Academy of Sciences 106:13691–13695. (First shock-wave synthesis)
Purevjav N., Okuchi T., Tomioka N., Wang X., and Hoffmann C. 2016. Quantitative analysis of hydrogen sites and occupancy in deep mantle hydrous wadsleyite by single crystal neutron diffraction. Scientific Reports doi:10.1038/srep34988. (Determination of hydrogen sites by single-crystal neutron diffraction)
Spinelloid-type Mg2SiO4 (phase ε)
Mineral name: poirierite (named after Jean-Paul Poirier)
Discovery: Tenham meteorite (L6), Suizhou meteorite (L6), Miami meteorite (H5)
High-resolution transmission electron microscopy image of ringwoodite (Rwd) with the lamellar poirierite.
＊References＊
Madon M. and Poirier J. P. 1983. Physics of the Earth and Planetary Interiors 33:31–44. (Theoretical prediction)
Tomioka N. and Okuchi T. 2017. Scientific Reports 7:17351. (Discovery)
Tomioka N., Okuchi T., Iitaka T., Miyahara M., Bindi L., and Xie X. 2020. CNMNC Newsletter 54, Eur. J. Mineral., 32. (Desciption as a new mineral species)
Remarks: This mineral has a smallest the smallest unit cell among all spinel and spinelloid structures.
Orthosilicate Mg2SiO4 (ζ-olivine)
Mineral name: unnamed
Discovery: NWA2737 meteorite (chassignite), NWA1950 meteorite (shergottite)
＊References＊
Van de Moortèle B., Reynard B., McMillan P. F., Wilson M., Beck P., Gillet Ph., and Jahn S. 2007. Earth and Planetary Science Letters 261:469–475. (Discovery)
Remarks: This mineral is regarded as a metastable high-pressure form of olivine produced at relatively low temperature.
Spinel-type Fe2SiO4
Mineral name: ahrensite (named after Thomas J. Ahrens)
Discovery: Tissint meteorite (shergottite), Umbarger meteorite (L6)
Fe2SiO4 spinel (Sp) embedded in phyllosilicate (Ps) in the Umbarger chondrite. (Courtesy of Z. Xie, Nanjing Univ.)
Ahrensite in the Martian meteorite Tissint. (Courtesy of C. Ma, Caltech)
＊References＊
Ringwood A. E. 1958. Geochimica et Cosmochimica Acta 13:303–321. (First synthesis)
Xie Z., Tomioka N., and Sharp T. 2002. American Mineralogist 87:1257–1260. (Discovery)
Hollister L. S., Bindi L., Yao N., Poirier G. R., Andronicos C. L., MacPherson G. J., Lin C., V. Distler V. V., Eddy M. P., Kostin A., Kryachko V., Steinhardt W. M., Yudovskaya M.,, John M. Eiler J. M., Guan Y., Clarke J. J., and Steinhardt P. J. 2014. Impact-induced shock and the formation of natural quasicrystals in the early solar system. Nature Communications, 5, 4040. (Discovery in a carbonaceous chondrite)
Ma C., Tschauner O., Beckett J. R., Liu Y., Rossman Sinogeikin S., Smith J., and Taylor L. 2016. Geochimica et Cosmochimica Acta 184:240–256. (Described as a new mineral species with full chemical and structural characterization)
Spinelloid-type Fe2SiO4 [phase III (β)]
Mineral name: asimowite (named after Paul A. Asimow)
Discovery: Suizhou meteorite (L6) , Quebrada Chimborazo 001 (CB3)
＊References＊
Bindi L., Brenker F. E., Nestola F., Koch T. E., Prior D. J., Lilly K., Krot A. N., Bizzaro M., and Xie, X. 2019. American Mineralogist 104:775–778. (Discovery)