Newsletter 64

The information given here is provided by the IMA Commission on New Minerals, Nomenclature and Classification for comparative purposes and as a service to mineralogists working on new species.

Each mineral is described in the following format:

Mineral name, if the authors agree on its release prior to the full description appearing in press

Chemical formula (ideal formula)

Mineral symbol

Type locality

Full authorship of proposal

E-mail address of corresponding author

Relationship to other minerals

Crystal system, Space group; Structure determined, yes or no

Unit-cell parameters

Strongest lines in the powder X-ray diffraction pattern

Type specimen repository and specimen number

Citation details for the mineral prior to publication of full description

Citation details concern the fact that this information will be published in the Mineralogical Magazine on a routine basis, as well as being added month by month to the Commission's web site.

It is still a requirement for the authors to publish a full description of the new mineral.

NO OTHER INFORMATION WILL BE RELEASED BY THE COMMISSION

NEW MINERAL PROPOSALS APPROVED IN OCTOBER 2021

IMA No. 2021-055

• Ferrotorryweiserite

• Rh₅Fe₁₀S₁₆

• Ftyw

• Sisim placer zone, Krasnoyarskiy kray, central Siberia, southwestern Eastern Sayans, Russia (54°44′58″ N, 93°09′08″ E)

• Andrei Y. Barkov*, Nadezhda D. Tolstykh, Nobumichi Tamura, Robert F. Martin, Andrew M. McDonald and Louis J. Cabri

• *E-mail: ore-minerals@mail.ru

• The Fe analogue of torryweiserite

• Trigonal: R $\overline 3$m

• a = 7.069(2), c = 34.286(11) Å

• 5.765(39), 5.714(61), 3.049(39), 2.795(100), 2.596(38), 1.767(44), 1.524(9), 1.503(35)

• Type material is deposited in the mineralogical collections of the Central Siberian Geological Museum, Sobolev Institute of Geology and Mineralogy, Akademik Koptyug Avenue, no. 3, 630090 Novosibirsk, Russia, catalogue number III-102/3

• How to cite: Barkov, A.Y., Tolstykh, N.D., Tamura, N., Martin, R.F., McDonald, A.M. and Cabri, L.J. (2021) Ferrotorryweiserite, IMA 2021-055. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-060

• Mikecoxite

• [CHg₄]OCl₂

• Mcx

• McDermitt open-pit mine, eastern margin of the McDermitt Caldera, Humboldt Co., Nevada, USA (41°55′11.5″ N, 117°48′45.8″ W)

• Mark A. Cooper, Gail E. Dunning, Frank C. Hawthorne*, Chi Ma, Anthony R. Kampf, John Spratt, Christopher J. Stanley and Andrew G. Christy

• *E-mail: frank.hawthorne@umanitoba.ca

• New structure type

• Monoclinic: P2₁/n; structure determined

• a = 10.164(5), b = 10.490(4), c = 6.547(3) Å, β = 90.04(1)°

• 5.49(34), 4.65(32), 2.989(81), 2.884(100), 2.673(79), 2.300(30), 2.045(30), 1.744(40)

• Type material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 76196 (holotype) and 76197 (cotype)

• How to cite: Cooper, M.A., Dunning, G.E., Hawthorne, F.C., Ma, C., Kampf, A.R., Spratt, J., Stanley, C.J. and Christy, A.G. (2021) Mikecoxite, IMA 2021-060. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-066

• Lepersonnite-(Nd)

• Lps-Nd

• Nd₄(UO₂)₂₄(SiO₄)₄(CO₃)₈(OH)₂₈⋅48H₂O

• Swambo deposit, 36 km west of Shinkolobwe, near Mindigi mine, Kambove District, Haut-Katanga, Democratic Republic of the Congo (11°05′43″ S, 26°13′23″ E)

• Jakub Plášil*, Anthony R. Kampf, Radek Škoda, Simon Philippo, Mael Guennou and Florias Mees

• *E-mail: plasil@fzu.cz

• The Nd analogue of lepersonnite-(Gd)

• Orthorhombic: Pnnm or Pnn2

• a = 16.13(1), b = 38.91(3), c = 11.765(6) Å

• 8.16(100), 3.66(57), 3.20(33), 3.11(21), 3.01(21), 2.86(22), 1.956(20), 1.902(23)

• Cotype material is deposited in the mineralogical collections of the Musée d'Histoire Naturelle, 25 rue Münster, L-2160 Luxembourg, Luxembourg, specimen no. WPV020, and the Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium, specimen no. RGM11529.1

• How to cite: Plášil, J., Kampf, A.R., Škoda, R., Philippo, S., Guennou, M. and Mees, F. (2021) Lepersonnite-(Nd), IMA 2021-066. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-067

• Reznitskyite

• CaMg(VO₄)F

• Rzs

• Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka peninsula, Far-Eastern Region, Russia (55°41′ N, 160°14′ E, 1200 m a.s.l.)

• Natalia N. Koshlyakova*, Igor V. Pekov, Marina F. Vigasina, Natalia V. Zubkova, Atali A. Agakhanov, Sergey N. Britvin, Evgeny G. Sidorov and Dmitry Y. Pushcharovsky

• *E-mail: nkoshlyakova@gmail.com

• The V analogue of tilasite

• Monoclinic: C2/c; structure determined

• a = 6.6912(7), b = 8.9395(7), c = 7.0587(8) Å, β = 113.08(1)°

• 3.686(26), 3.250(66), 3.082(100), 2.854(34), 2.683(33), 2.631(44), 2.531(25), 1.749(25)

• Type material is deposited in the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5734/1

• How to cite: Koshlyakova, N.N., Pekov, I.V., Vigasina, M.F., Zubkova, N.V., Agakhanov, A.A., Britvin, S.N., Sidorov, E.G. and Pushcharovsky, D.Y. (2021) Reznitskyite, IMA 2021-067. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-068

• Penriceite

• [Mg(H₂O)₆][Na(H₂O)₂Al₃(PO₄)₂F₆]⋅H₂O

• Prc

• Penrice marble quarry, 2 km north of Angaston, Barossa Valley, South Australia, Australia (34°28′54″ S, 139°02′48″ E)

• Peter Elliott, Ian E. Grey*, Colin M. Macrae, Anthony R. Kampf and Cameron Davidson

• *E-mail: ian.grey@csiro.au

• The F-dominant analogue of aldermanite

• Monoclinic: P2₁/c; structure determined

• a = 13.478(3), b = 9.971(2), c = 6.999(1) Å, β = 97.20(3)°

• 13.39(100), 8.00(30), 5.718(12), 5.562(26), 3.284(4), 3.004(5), 2.855(16), 2.782(15)

• Type material is deposited in the mineralogical collections of the Museum of South Australia, North Terrace, Adelaide 5000, South Australia, Australia, catalogue number G32227 (holotype), and the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 76158 (cotype)

• How to cite: Elliott, P., Grey, I.E., Macrae, C.M., Kampf, A.R. and Davidson, C. (2021) Penriceite, IMA 2021-068. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-069

• Matthiasweilite

• PbTe⁴⁺O₃

• Mtw

• On a dump of the Delamar mine, Delamar district, Lincoln Co., Nevada, USA (37°27′45″ N, 114°46′08″)

• Anthony R. Kampf*, Owen P. Missen, Stuart J. Mills, Chi Ma, Robert M. Housley, Marek Chorazewicz, Joe Marty and Mark Coolbaugh

• *E-mail: akampf@nhm.org

• A dimorph of plumbotellurite

• Triclinic: P $\overline 1$; structure determined

• a = 7.0256(4), b = 10.6345(6), c = 11.9965(8) Å, α = 78.513(6), β = 83.104(6), γ = 84.083(6)°

• 3.270(77), 3.146(100), 3.010(28), 2.815(33), 2.564(18), 1.952(31), 1.784(18), 1.667(18)

• Type material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 76156 (holotype) and 76157 (cotype), and the Museums Victoria, GPO Box 666, Melbourne 3001, Victoria, Australia, specimen number M55535 (cotype)

• How to cite: Kampf, A.R., Missen, O.P., Mills, S.J., Ma, C., Housley, R.M., Chorazewicz, M., Marty, J. and Coolbaugh, M. (2021) Matthiasweilite, IMA 2021-069. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-070

• Jingwenite-(Y)

• YAlV⁴⁺(SiO₄)O₂(OH)₂

• Jw-Y

• Yushui Cu polymetallic deposit, about 16 km northeast of Meizhou City, Guangdong Province, China (24°25′30″ N, 116°10′45″ E)

• Peng Liu, Xiangping Gu*, Wenlan Zhang, Huan Hu, Xiaodan Chen, Wenlei Song, Xiaolin Wang, Miao Yu and Nigel J. Cook

• *E-mail: guxp2004@163.com

• New structure type

• Monoclinic: I2/a; structure determined

• a = 9.4821(2), b = 5.8781(1), c = 19.3987(4) Å, β = 90.165(2)°

• 9.73(58), 5.011(62), 4.274(36), 3.636(30), 3.216(51), 2.676(100), 2.582(95), 2.049(82)

• Type material is deposited in the mineralogical collections of the Geological Museum of China, No. 16, Yangrou Hutong, Xisi, Beijing 100031, People's Republic of China, catalogue number M16122

• How to cite: Liu, P., Gu, X., Zhang, W., Hu, H., Chen, X., Song, W., Wang, X., Yu, M. and Cook, N.J. (2021) Jingwenite-(Y), IMA 2021-070. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

NEW MINERAL PROPOSALS APPROVED IN NOVEMBER 2021

IMA No. 2021-004

• Paulgrothite

• Cu₉Fe³⁺O₄(PO₄)₄Cl₃

• Plgr

• Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka peninsula, Far-Eastern Region, Russia (55°41′ N, 160°14′ E, 1200 m a.s.l.)

• Oleg I. Siidra*, Evgeny V. Nazarchuk, Leonid A. Pautov, Artem S. Borisov, Anatoly N. Zaitsev, Evgeniya Y. Avdontseva and Vladimir N. Bocharov

• *E-mail: o.siidra@spbu.ru

• New structure type

• Orthorhombic: Cmc2₁; structure determined

• a = 5.90(1), b = 15.66(4), c = 17.33(4) Å

• 5.317(18), 4.667(24), 3.561(37), 3.236(17), 2.909(100), 2.452(65), 2.358(15), 2.347(26)

• Type material is deposited in the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5595/1

• How to cite: Siidra, O.I., Nazarchuk, E.N., Pautov, L.A., Borisov, A.S., Zaitsev, A.N., Avdontseva, E.Y. and Bocharov, V.N. (2021) Paulgrothite, IMA 2021-004. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-071

• Stibioústalečite

• Cu₆Cu₆(Sb₂Te₂)Se₁₃

• Súč

• Ústaleč abandoned mine, 500 m northeast of the Ústaleč village, 15 km west of Horažďovice, South-Western Bohemia, Czech Republic (49°19′14″ N, 13°30′15″ E)

• Jiří Sejkora*, Jakub Plášil and Emil Makovicky

• *E-mail: jiri.sejkora@nm.cz

• Tetrahedrite group

• Cubic: I $\overline 4$3m; structure determined

• a = 10.828(4) Å

• 3.828(10), 3.126(100), 2.894(11), 2.552(9), 1.977(11), 1.914(71), 1.632(33), 1.353(9)

• Type material is deposited in the mineralogical collections of the Department of Mineralogy and Petrology, National Museum in Prague, Cirkusová 1740, 19300 Praha 9, Czech Republic, catalogue number P1P 7/2021

• How to cite: Sejkora, J., Plášil, J. and Makovicky, E. (2021) Stibioústalečite, IMA 2021-071. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-072

• Redmondite

• [Pb₈O₂Zn(OH)₆](S₂O₃)₄

• Rdm

• Redmond mine, Haywood Co., North Carolina, USA (35°40′49″ N, 83°01′07″ W)

• Anthony R. Kampf*, Jason B. Smith, John M. Hughes, Chi Ma and Christopher Emproto

• *E-mail: akampf@nhm.org

• New structure type

• Monoclinic: P2₁/c; structure determined

• a = 9.1672(4), b = 10.6576(4), c = 14.062(1) Å, β = 101.173(7)°

• 6.56(64), 5.01(32), 3.442(100), 3.173(32), 2.912(35), 2.847(42), 2.479(38), 2.280(27)

• Cotype material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 76160, 76161 and 76162

• How to cite: Kampf, A.R., Smith, J.B., Hughes, J.M., Ma, C. and Emproto, C. (2021) Redmondite, IMA 2021-072. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-073

• Hydroredmondite

• [Pb₈O₂Zn(OH)₆](S₂O₃)₄⋅2H₂O

• Hrdm

• Redmond mine, Haywood Co., North Carolina, USA (35°40′49″ N, 83°01′07″ W)

• Anthony R. Kampf*, Jason B. Smith, John M. Hughes, Chi Ma and Christopher Emproto

• *E-mail: akampf@nhm.org

• New structure type

• Monoclinic: P2₁/n; structure determined

• a = 12.5991(9), b = 9.2819(4), c = 12.9774(9) Å, β = 90.443(6)°

• 9.05(29), 6.49(100), 4.83(34), 3.638(46), 3.017(52), 2.825(40), 2.794(27), 2.729(32)

• Cotype material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 76163, 76164, 76165 and 76166

• How to cite: Kampf, A.R., Smith, J.B., Hughes, J.M., Ma, C. and Emproto, C. (2021) Hydroredmondite, IMA 2021-073. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-074

• Pertoldite

• GeO₂

• Pert

• In the central part of a burning coal mine dump of the abandoned Kateřina mine, east of Radvanice village, about 12 km east of Trutnov town, Hradec Králové region, Czech Republic (50°33′39.0″ N, 16°03′56.2″ E)

• Vladimír Žáček*, Radek Škoda, František Laufek, Jiří Sejkora and Jakub Haifler

• *E-mail: vladimir.zacek@geology.cz

• A dimorph of argutite

• Trigonal: P3₁21 or P3₂21

• a = 4.980(5), c = 5.644(4) Å

• 4.315(44), 3.425(100), 2.490(31), 2.360(41), 2.278(29), 1.867(31), 1.418(31), 1.412(37)

• Type material is deposited in the collections of the Department of Mineralogy and Petrology, National Museum in Prague, Cirkusová 1740, 19300 Praha 9, Czech Republic, catalogue number P1P 31/2021

• How to cite: Žáček, V., Škoda, R., Laufek, F., Sejkora, J. and Haifler, J. (2021) Pertoldite, IMA 2021-074. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-075

• Oldsite

• K₂Fe²⁺[(UO₂)(SO₄)₂]₂(H₂O)₈

• Ods

• North Mesa mine group, Temple Mountain, San Rafael district, Emery Co., Utah, USA

• Jakub Plášil*, Anthony R. Kampf, Chi Ma and Joy Desor

• *E-mail: plasil@fzu.cz

• The Fe analogue of svornostite

• Orthorhombic: Pmn2₁; structure determined

• a = 12.893(3), b = 8.276(2), c = 11.239(2) Å

• 8.29 (59), 6.47(82), 5.10(62), 4.65(100), 3.332(55), 3.020(63), 2.670(51), 2.106(56)

• Type material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 76159

• How to cite: Plášil, J., Kampf, A.R., Ma, C. and Desor, J. (2021) Oldsite, IMA 2021-075. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-077

• Madeiraite

• Na₂Ca₂Fe₂Zr₂(Si₂O₇)₂O₂F₂

• Mde

• Terra do Batista gabbro outcrop, Porto da Cruz, Machico, Madeira Island, Portugal (32°46′01″ N, 16°50′29″ W); Serrado gabbro outcrop, Porto da Cruz, Machico, Madeira Island, Portugal (32°45′30″ N, 16°49′41″ W)

• Stuart J. Mills*, Fabrice Dal Bo, Pedro Alves, Henrik Friis and Owen P. Missen

• *E-mail: smills@museum.vic.gov.au

• Wöhlerite group

• Monoclinic: P2₁/a; structure determined

• a = 10.880(1), b = 10.0442(7), c = 7.2250(7) Å, β = 108.78(1)°

• 6.780(26), 4.007(22), 3.243(37), 2.928(84), 2.839(100), 1.807(23), 1.775(24), 1.524(23)

• Type material is deposited in the mineralogical collections of the Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia, registration number M55555 (holotype), and the Natural History Museum, University of Oslo, P.O. Box 1172, Blindern, 0318 Oslo, Norway registration number KNR 44332 (cotype)

• How to cite: Mills, S.J., Dal Bo, F., Alves, P., Friis, H. and Missen, O.P. (2021) Madeiraite, IMA 2021-077. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-079

• Petermegawite

• Al₆(Se⁴⁺O₃)₃[SiO₃(OH)](OH)₉⋅10H₂O

• Pmw

• El Dragón mine, Antonio Quijarro Province, Potosí Department, Bolivia (19°49′15″ S, 65°55′00″ W)

• Hexiong Yang*, Xiangping Gu, Robert A. Jenkins, Ronald B. Gibbs, James A. McGlasson and Michael M. Scott

• *E-mail: hyang@arizona.edu

• New structure type

• Orthorhombic: Cmc2₁; structure determined

• a = 16.2392(2), b = 10.9637(1), c = 15.3367(2) Å

• 7.824(100), 7.642(88), 5.839(53), 5.580(83), 5.514(88), 4.860(67), 4.496(49), 3.017(81)

• Type material is deposited in the collections of the University of Arizona Mineral Museum, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA, catalogue no. 22711 (holotype), and the RRUFF Project, deposition no. R210008 (cotype)

• How to cite: Yang, H., Gu, X., Jenkins, R.A., Gibbs, R.B., McGlasson, J.A. and Scott, M.M. (2021) Petermegawite, IMA 2021-079. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-080

• Xuwenyuanite

• Ag₉Fe³⁺Te₂S₄

• Xuw

• Bajiazi lead-zinc deposit, about 310 km southwest of Shengyang City, Jianchang County, Liaoning Province, China (40°35′30″ N, 120°02′16″ E)

• Xiangping Gu*, Ziping Wang and Wenfeng Zhu

• *E-mail: guxp2004@163.com

• A dimorph of chenguodaite

• Cubic: F $\overline 4$3m; structure determined

• a = 11.0732(2) Å

• 6.409(100), 3.338(52), 3.191(79), 2.762(70), 2.254(73), 2.126(88), 1.952(59), 1.303(15)

• Type material is deposited in the mineralogical collections of the Geological Museum of China, No. 16, Yangrou Hutong, Xisi, Beijing 100031, People's Republic of China, catalogue number M16128

• How to cite: Gu, X., Wang, Z. and Zhu, W. (2021) Xuwenyuanite, IMA 2021-080. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

IMA No. 2021-040a

• Bortolanite

• Ca₂(Ca_1.5Zr_0.5)Na(NaCa)Ti(Si₂O₇)₂(OF)F₂

• Btln

• Bortolan quarry, Poços de Caldas massif, Minas Gerais, Brazil (21°46′38″ S, 46°37′58″ W)

• Maxwell C. Day, Elena Sokolova*, Frank C. Hawthorne, László Horváth and Elsa Pfenninger-Horváth

• *E-mail: elena_sokolova@umanitoba.ca

• Seidozerite supergroup

• Triclinic: P $\overline 1$; structure determined

• a = 9.615(3), b = 5.725(2), c = 7.316(2) Å, α = 89.91(1), β = 101.14(1), γ = 100.91(1)°

• 3.086(61), 2.975(100), 2.844(21), 2.639(30), 2.510(24), 1.908(31), 1.829(26), 1.704(22)

• Type material is deposited in the mineralogical collections of the Canadian Museum of Nature, 240 McLeod St, Ottawa, ON K2P 2R1, Canada, registration number CMNMC 88727

• How to cite: Day, M.C., Sokolova, E., Hawthorne, F.C., Horváth, L. and Pfenninger-Horváth, E. (2021) Bortolanite, IMA 2021-040a. CNMNC Newsletter 64; Mineralogical Magazine, 85, https://doi.org/10.1180/mgm.2021.93

NOMENCLATURE/CLASSIFICATION PROPOSALS APPROVED IN NOVEMBER 2021

IMA 21-G: Hiärneite: crystal structure, chemical formula and classification

Proposal 21-G is accepted, and based on SCXRD data the formula of hiärneite is revised from (Ca,Na,Mn²⁺)₂(Zr,Mn³⁺)₅(Sb,Ti,Fe³⁺)₂O₁₆ to Ca₂Zr₄Mn³⁺SbTiO₁₆. Hiärneite belongs to the calzirtite group of minerals, which also includes calzirtite [Ca₂Zr₅Ti₂O₁₆] and the structurally related cubic mineral tazheranite [(Zr,Ti,Ca)(O, □)₂].

IMA 21-H: Redefinition of bixbyite and definition of bixbyite-(Fe) and bixbyite-(Mn)

Proposal 21-H is accepted. The name ‘bixbyite’ becomes a series name for material with a bixbyite structure, space group Ia $\overline 3$, and Fe³⁺ or Mn³⁺ as the dominant trivalent cation (it also includes the orthorhombic polytype of Mn₂O₃, with space group Pcab). Bixbyite-(Fe) is defined as the Fe³⁺ dominant part of the series, with an ideal formula (Fe,Mn)₂O₃, and bixbyite-(Mn) is defined as the Mn³⁺ dominant part of the series, with an ideal formula Mn₂O₃.