NEW MINERAL PROPOSALS APPROVED IN APRIL 2019

IMA No. 2018-141

• Andymcdonaldite

• Fe₂TeO₆

• Wildcat prospect, NW portion of the Detroit District, Juab Co., Utah, USA

• Mati Raudsepp*, Mark F. Coolbaugh, John K. McCormack, Edith Czech and Rhy McMillan

• *E-mail: [email protected]

• Known synthetic analogue

• Tetragonal: P4₂/mnm

• a = 4.6222(9), c = 9.077(3) Å

• 4.538(12), 4.119(35), 3.268(100), 2.652(10), 2.531(58), 2.311(13), 1.707(48), 1.634(14)

• Type material is deposited in the mineralogical collections of the Smithsonian National Museum of Natural History, 10th St. & Constitution Ave., Washington, DC 20560, USA, catalogue number NMNH 177134

• How to cite: Raudsepp, M., Coolbaugh, M.F., McCormack, J.K., Czech, E. and McMillan, R. (2019) Andymcdonaldite, IMA 2018-141. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-142

• Aluminosugilite

• KNa₂Al₂Li₃Si₁₂O₃₀

• Cerchiara mine, Faggiona, Borghetto Vara-Pignone, La Spezia, Liguria, Italy (44°11'57”N, 9°42'1”E)

• Mariko Nagashima*, Chihiro Fukuda, Takashi Matsumoto, Teruyoshi Imaoka, Gianluca Odicino and Gianluca Armellino

• *E-mail: [email protected]

• Osumilite group

• Hexagonal: P6/mcc; structure determined

• a = 9.9830(4), c = 13.9667(5) Å

• 4.32(100), 4.06(38), 3.67(14), 3.48(30), 3.18(92), 2.86(70), 2.71(18), 2.49(18)

• Type material is deposited in the mineralogical collections of the National Museum of Nature and Science, Tsukuba, Japan, specimen numbers NSM-MF-16503

• How to cite: Nagashima, M., Fukuda, C., Matsumoto, T., Imaoka, T., Odicino, G. and Armellino, G. (2019) Aluminosugilite, IMA 2018-142. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-150

• Siwaqaite

• Ca₆Al₂(CrO₄)₃(OH)₁₂·26H₂O

• North Siwaqa complex, Lisdan-Siwaqa Fault, Hatrurim Complex, ca. 60 km S of Amman, Jordan (31°24'15”N, 36°14'34”E)

• Rafał Juroszek*, Biljana Krüger, Irina O. Galuskina, Hannes Krüger, Yevgeny Vapnik and Evgeny V. Galuskin

• *E-mail: [email protected]

• The Cr analogue of ettringite

• Trigonal: P31c; structure determined

• a = 11.3640(2), c = 21.4485(2) Å

• 9.841(100), 5.682(65), 5.021(16), 4.709(38), 3.900(29), 3.280(17), 3.279(33), 2.224(16)

• 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 5277/1

• How to cite: Juroszek, R., Krüger, B., Galuskina, I.O., Krüger, H., Vapnik, Y. and Galuskin, E.V. (2019) Siwaqaite, IMA 2018-150. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-154

• Luxembourgite

• AgCuPbBi₄Se₈

• Bivels, Luxembourg (49°57'8”N, 6°10'41”E)

• Simon Philippo, Frédéric Hatert*, Yannick Bruni and Pietro Vignola

• *E-mail: [email protected]

• Isostructural with watkinsonite and litochlebite

• Monoclinic: P2₁/m; structure determined

• a = 13.002(1), b = 4.1543(3), c = 15.312(2) Å, β = 108.92(1)°

• 4.61(20), 3.59(20), 2.984(100), 2.425(20), 2.085(60), 1.916(20), 1.355(30), 1.188(30)

• Type material is deposited in the mineralogical collections of the Natural History Museum of Luxembourg, Rue Münster 25, L-2560 Luxembourg, Luxembourg, catalogue number FD040, and the Laboratory of Mineralogy, University of Liège, Bâtiment B18, Sart Tilman, B-4000 Liège, Belgium, catalogue number 21302

• How to cite: Philippo, S., Hatert, F., Bruni, Y. and Vignola, P. (2019) Luxembourgite, IMA 2018-154. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-156

• Tsikourasite

• Mo₃Ni₂P_1+x (x < 0.25)

• Agios Stefanos mine, ca. 10 km S of the Domokos village, Othrys ophiolite, Greece (39°4'59”N, 22°25'59”E)

• Federica Zaccarini*, Luca Bindi, Elena Ifandi, Tassos Grammatikopoulos, Chris J. Stanley, Giorgio Garuti and Daniela Mauro

• *E-mail: [email protected]

• Known synthetic analogue

• Cubic: F4̅3m; structure determined

• a = 10.8215(5) Å

• 2.705(20), 2.483(18), 2.209(65), 2.083(100), 1.913(32), 1.803(12), 1.275(26), 1.089(12)

• Type material is deposited in the mineralogical collections of the Museo di Storia Naturale, Università di Firenze, Via La Pira 4, I-50121, Firenze, Italy, catalogue number 3296/I

• How to cite: Zaccarini, F., Bindi, L., Ifandi, E., Grammatikopoulos, T., Stanley, C.J., Garuti, G. and Mauro, D. (2019) Tsikourasite, IMA 2018-156. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-157

• Laurentthomasite

• Mg₂K(Be₂Al)Si₁₂O₃₀

• 40 km E of the village of Betroka, in a rural area named Beravina, close to the small village of Ambaro, Toliara province, Madagascar (23°21'0”S, 46°25'0”E)

• Cristiano Ferraris*, Isabella Pignatelli, Fernando Cámara, Sylvain Ponti, Martin Schreyer, Gian Carlo Parodi and Fengxia Wei

• *E-mail: [email protected]

• The Mg analogue of milarite

• Hexagonal: P6/mcc; structure determined

• a = 9.95343(6), c = 14.15583(8) Å

• 7.055(2), 4.965(6), 4.302(2), 4.064(8), 3.533(3), 3.171(10), 2.881(8), 2.372(4)

• Type material is deposited in the mineralogical collections of the Muséum National d'Histoire Naturelle, 61 rue Buffon, 75005 Paris, France, catalogue numbers 218.1_a (holotype), 218.1_b and 218.1_c (cotypes)

• How to cite: Ferraris, C., Pignatelli, I., Cámara, F., Ponti, S., Schreyer, M., Parodi, G.C. and Wei, F. (2019) Laurentthomasite, IMA 2018-157. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-158

• Kahlenbergite

• KAl₁₁O₁₇

• Ca. 300 m NE of the Parsa Mt, Negev Desert, Hatrurim Basin, Israel (31°12.18'N, 36°15.31'E)

• Biljana Krüger*, Evgeny V. Galuskin, Irina O. Galuskina, Hannes Krüger and Yevgeny Vapnik

• *E-mail: [email protected]

• The K analogue of diaoyudaoite

• Hexagonal: P6₃/mmc; structure determined

• a = 5.64860(6), c = 22.8970(3) Å

• 11.448(100), 5.724(15), 2.824(14), 2.719(34), 2.533(26), 2.059(12), 1.610(13), 1.412(19)

• 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 5295/1

• How to cite: Krüger, B., Galuskin, E.V., Galuskina, I.O., Krüger, H. and Vapnik, Y. (2019) Kahlenbergite, IMA 2018-158. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-159

• Scorticoite

• Mn₆(Sb☐)_Σ2(SiO₄)₂O₃(OH)₃

• Scortico Mn ore deposit, Fivizzano, Apuan Alps, Massa Carrara, Tuscany, Italy (44°07'39”N, 10°07'12”E)

• Cristian Biagioni*, Elena Bonaccorsi, Anthony R. Kampf, Federica Zaccarini, Ulf Hålenius and Ferdinando Bosi

• *E-mail: [email protected]

• Welinite group

• Trigonal: P3; structure determined

• a = 8.205(1), c = 4.774(1) Å

• 3.105(s), 2.858(s), 2.676(ms), 2.332(ms), 1.787(s), 1.685(m), 1.552(m)

• Type material is deposited in the mineralogical collections of the Museo di Storia Naturale, Università di Pisa, Via Roma 79, Calci, Pisa, Italy, catalogue number 19908

• How to cite: Biagioni, C., Bonaccorsi, E., Kampf, A.R., Zaccarini, F., Hålenius, U. and Bosi, F. (2019) Scorticoite, IMA 2018-159. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-160

• Potassic-hastingsite

• KCa₂(Fe²⁺₄Fe³⁺)(Si₆Al₂)O₂₂(OH)₂

• Danailingou, Tongxing town, Keshiketeng Banner, Inner Mongolia, China (43°43'18”N, 117°34'37”E)

• Guangming Ren*, Guowu Li, Jiaxin Shi, Xiangping Gu, Guang Fan, Apeng Yu, Qiuxiao Liu and Ganfu Shen

• *E-mail: [email protected]

• Amphibole supergroup

• Monoclinic: C2/m; structure determined

• a = 9.9405(7), b = 18.256(2), c = 5.3501(3) Å, β = 105.117(5)°

• 8.504(100), 3.417(36), 3.155(63), 2.735(71), 2.623(35), 2.570(34), 2.365(29), 2.179(30)

• Type material is deposited in the mineralogical collections of the Geological Museum of China, Beijing, China, catalogue number M13815

• How to cite: Ren, G., Li, G., Shi, J., Gu, X., Fan, G., Yu, A., Liu, Q. and Shen, G. (2019) Potassic-hastingsite, IMA 2018-160. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-161

• Rumoiite

• AuSn₂

• Minamichiyoda, Shosanbetsu village, Rumoi Subprefecture, Hokkaido, Japan (44°31'21”N, 141°46'51”E)

• Daisuke Nishio-Hamane* and Katsuyuki Saito

• *E-mail: [email protected]

• Known synthetic analogue

• Orthorhombic: Pbca

• a = 6.905(2), b = 7.017(2), c = 11.797(3) Å

• 4.542(58), 3.774(48), 2.950(100), 2.711(52), 2.409(41), 2.244(56), 2.136(47), 2.123(65)

• Type material is deposited in the mineralogical collections of the National Museum of Nature and Science, Tsukuba, Japan, specimen number NSM-M46178 (holotype) and M46179 (cotype)

• How to cite: Nishio-Hamane, D. and Saito, K. (2019) Rumoiite, IMA 2018-161. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-162

• Shosanbetsuite

• Ag₃Sn

• Minamichiyoda, Shosanbetsu village, Rumoi Subprefecture, Hokkaido, Japan (44°31'21”N, 141°46'51”E)

• Daisuke Nishio-Hamane* and Katsuyuki Saito

• *E-mail: [email protected]

• Known synthetic analogue

• Orthorhombic: Pmmn

• a = 5.998(5), b = 4.7736(9), c = 5.154(3) Å

• 2.592(10), 2.586(7), 2.389(30), 2.275(100), 2.267(85), 1.756(78), 1.356(73), 1.354(53)

• Type material is deposited in the mineralogical collections of the National Museum of Nature and Science, Tsukuba, Japan, specimen number NSM-M46178 (holotype) and M46179 (cotype)

• How to cite: Nishio-Hamane, D. and Saito, K. (2019) Shosanbetsuite, IMA 2018-162. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-165

• Giacovazzoite

• K₅Fe³⁺₃O(SO₄)₆·10H₂O

• Monte Arsiccio mine, Stazzema (LU), Apuan Alps, Tuscany, Italy (43°58'N, 10°17'E)

• Cristian Biagioni*, Luca Bindi, Daniela Mauro and Marco Pasero

• *E-mail: [email protected]

• Known synthetic analogue

• Monoclinic: P2₁/c; structure determined

• a = 9.4797(2), b = 18.4454(5), c = 18.0540(4) Å, β = 92.626(2)°

• 9.1(s), 8.2(vs), 4.15(mw), 4.02(mw), 3.442(m), 3.371(m), 3.005(m), 2.968(m)

• Type material is deposited in the mineralogical collections of the Museo di Storia Naturale, Università di Pisa, Via Roma 79, Calci, Pisa, Italy, catalogue number 19896

• How to cite: Biagioni, B., Bindi, L., Mauro, D. and Pasero, M. (2019) Giacovazzoite, IMA 2018-165. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-166

• Pseudomeisserite-(NH₄)

• (NH₄)₂Na₄[(UO₂)₂(SO₄)₅]·4H₂O

• Blue Lizard mine, Red Canyon, White Canyon District, San Juan Co., Utah, USA (37°33'26”N, 110°17'44”W)

• Anthony R. Kampf*, Travis A. Olds, Jakub Plášil, Barbara P. Nash and Joe Marty

• *E-mail: [email protected]

• New structure type

• Monoclinic: P2₁/c; structure determined

• a = 13.1010(3), b = 10.0948(2), c = 19.494(1) Å, β = 104.285(7)°

• 12.69(76), 8.88(55), 6.83(84), 6.01(100), 4.593(51), 4.414(57), 3.959(67), 3.135(76)

• 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 67621 and 67622

• How to cite: Kampf, A.R., Olds, T.A., Plášil, J., Nash, B.P. and Marty, J. (2019) Pseudomeisserite-(NH₄), IMA 2018-166. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-167

• Gobelinite

• CoCu₄(SO₄)₂(OH)₆·6H₂O

• Cap Garonne mine (pillar 78b in the north mine), Var, Provence-Alpes-Côte d'Azur, France (43°4'53”N, 6°1'55”E – type locality); Schlänger und Eichert vein of the Eisenzecher Zug mine, Eiserfeld, Siegerland, North Rhine-Westphalia, Germany (50°49'9”N, 7°59'14”E – cotype locality)

• Stuart J. Mills*, Uwe Kolitsch, Georges Favreau, William D. Birch, Valérie Galea-Clolus and Johannes Markus Henrich

• *E-mail: [email protected]

• The Co analogue of ktenasite

• Monoclinic: P2₁/c; structure determined

• a = 5.599(1), b = 6.084(1), c = 23.676(5) Å, β = 95.22(3)°

• 11.870(100), 5.924(40), 4.883(10), 4.825(15), 3.946(15), 2.956(15), 2.663(20), 2.561(15)

• Type material is deposited in the mineralogical collections of Geosciences, Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia, registration number M54565 (Cap Garonne), and the Naturhistorisches Museum, Burgring 7, A-1010 Wien, Austria, registration number O 1045 (Eisenzecher Zug)

• How to cite: Mills, S.J., Kolitsch, U., Favreau, G., Birch, W.D., Galea-Clolus, V. and Henrich, J.M. (2019) Gobelinite, IMA 2018-167. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2018-108a

• Fluorapophyllite-(Cs)

• CsCa₄(Si₈O₂₀)F(H₂O)₈

• Darai-Pioz glacier, Alai mountain range, Tien-Shan, Rashtskii district, Tajikistan (39°30'N, 70°40'E)

• Atali A. Agakhanov, Leonid A. Pautov, Anatoly V. Kasatkin, Elena Sokolova, Maxwell C. Day, Frank C. Hawthorne, Vladimir Y. Karpenko, Vyacheslav A. Muftakhov, Igor V. Pekov, Fernando Cámara Artigas and Sergey N. Britvin

• *E-mail: [email protected]

• Apophyllite group

• Tetragonal: P4/nmc

• a = 9.060(6), c = 15.741(11) Å

• 7.870(100), 3.935(100), 3.602(55), 2.974(84), 2.515(73), 2.486(71), 2.119(42), 2.030(45)

• 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 5280/1

• How to cite: Agakhanov, A.A., Pautov, L.A., Kasatkin, A.V., Sokolova, E., Day, M.C., Hawthorne, F.C., Karpenko, V.Y., Muftakhov, V.A., Pekov, I.V., Cámara Artigas, F. and Britvin, S.N. (2019) Fluorapophyllite-(Cs), IMA 2018-108a. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

NEW MINERAL PROPOSALS APPROVED IN MAY 2019

IMA No. 2019-001

• Smamite

• Ca₂Sb(OH)₄[H(AsO₄)₂]·6H₂O

• Giftgrube mine, St. Jacques vein, Rauenthal, Sainte Marie-aux-Mines, Haut-Rhin province, France (48°13'28”N, 7°9'7”E)

• Jakub Plášil*, Anthony R. Kampf, Nicolas Meisser, Cédric Lheur, Thierry Brunsperger and Radek Škoda

• *E-mail: [email protected]

• New structure type

• Triclinic: P1̅; structure determined

• a = 6.8207(4), b = 8.0959(4), c = 8.2130(6) Å, α = 95.834(7), β = 110.762(8), γ = 104.012(7)°

• 7.56(41), 6.03(60), 5.66(47), 5.07(100), 3.992(43), 3.783(36), 2.858(51), 2.766(31)

• Type material is deposited in the mineralogical collections of the Musée Cantonal de Géologie, University of Lausanne, Anthropole, Dorigny, CH-1015 Lausanne, Switzerland, catalogue number MGL 093481 (holotype), 093482 and 093481 (cotypes), and the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 67169 (cotype)

• How to cite: Plášil, J., Kampf, A.R., Meisser, N., Lheur, C., Brunsperger, T. and Škoda, R. (2019) Smamite, IMA 2019-001. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2019-002

• Caseyite

• [(V⁵⁺O₂)Al_7.5(OH)₁₅(H₂O)₁₃]₂[H₂V⁴⁺V⁵⁺₉O₂₈][V⁵⁺₁₀O₂₈]₂·90H₂O

• West Sunday mine, Slick Rock district, San Miguel Co., Colorado, USA (38°4'48.03”N, 108°49′18.07”W); Packrat mine, near Gateway, Mesa Co., Colorado, USA (38°38'51.28”N, 109°2'49.77”W); Burro mine, Slick Rock district, San Miguel Co., Colorado, USA (38°2'42”N, 108°53'23”W)

• Anthony R. Kampf*, Mark A. Cooper, John M. Hughes, Barbara P. Nash, Joe Marty and Frank C. Hawthorne

• *E-mail: [email protected]

• New structure type

• Monoclinic: P2₁/n; structure determined

• a = 14.123(8), b = 31.00(1), c = 21.95(1) Å, β = 97.961(8)°

• 17.798(92), 15.499(100), 12.749(26), 12.620(33), 10.869(16), 9.332(11), 9.016(14), 8.899(43)

• 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 numbers 73526 (Packrat – holotype), 73527 and 73528 (Packrat – cotypes), 73529 (West Sunday – cotype), 73530 and 73531 (Burro – cotypes)

• How to cite: Kampf, A.R., Cooper, M.A., Hughes, J.M., Nash, B.P., Marty, J. and Hawthorne, F.C. (2019) Caseyite, IMA 2019-002. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2019-005

• Langhofite

• Pb₂(OH)[WO₄(OH)]

• Långban deposit, Filipstad district, Värmland, Sweden (59.85°N, 14.26°E, 215 m a.s.l.)

• Dan Holtstam*, Fernando Cámara and Andreas Karlsson

• *E-mail: [email protected]

• New structure type

• Triclinic: P1̅; structure determined

• a = 6.6118(3), b = 7.0748(4), c = 7.3264(4) Å, α = 118.125(6), β = 94.503(5), γ = 101.146(5)°

• 6.04(24), 3.330(17), 3.259(22), 3.181(19), 3.079(24), 3.016(100), 2.053(20), 2.050(18)

• Type material is deposited in the mineralogical collections of the Department of Geosciences, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden, collection number GEO-NRM 20030044

• How to cite: Holtstam, D., Cámara, F. and Karlsson, A. (2019) Langhofite, IMA 2019-005. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

IMA No. 2019-006

• Magnanelliite

• K₃Fe³⁺₂(SO₄)₄(OH)(H₂O)₂

• Monte Arsiccio mine, Stazzema, Apuan Alps, Tuscany, Italy (43°58'N, 10°17'E)

• Cristian Biagioni, Luca Bindi and Anthony R. Kampf

• *E-mail: [email protected]

• The Fe³⁺ analogue of alcaparrosaite

• Monoclinic: C2/c; structure determined

• a = 7.5491(3), b = 16.8652(6), c = 12.1574(4) Å, β = 94.064(1)°

• 6.9(m), 4.91(mw), 3.612(mw), 3.427(mw), 3.300(mw), 3.085(s), 3.006(m), 2.704(m)

• Type material is deposited in the mineralogical collections of the Museo di Storia Naturale, Università di Pisa, Via Roma 79, Calci (Pisa, Italy), catalogue number 19894 (holotype), and the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 67241 (cotype)

• How to cite: Biagioni, C., Bindi, L. and Kampf, A.R. (2019) Magnanelliite, IMA 2019-006. CNMNC Newsletter No. 49: Mineralogical Magazine, 83, doi:10.1180/mgm.2019.35.

NOMENCLATURE PROPOSALS APPROVED IN MARCH 2019

IMA 18-C: Redefinition of calumetite and discreditation of vondechenite

• Proposal 18-C is accepted, and calumetite is redefined from Cu(OH,Cl)₂·2H₂O to CaCu₄(OH)₈Cl₂·3.5H₂O. Vondechenite (IMA2016-65), identical to calumetite, is consequently discredited.

IMA 18-I: Nomenclature of minerals of the rhodonite group

• Proposal 18-I is accepted, and the rhodonite group is established. Currently it consists of two mineral species having the following end-member formulae: rhodonite, ^M5Ca^M1–M3Mn₃^M4MnSi₅O₁₅, and ferrorhodonite ^M5Ca^M1–M3Mn₃^M4FeSi₅O₁₅.

IMA 19-A: Redefinition of tsugaruite

• Proposal 19-A is accepted, and tsugaruite is redefined as a lead-arsenic chloro-sulfosalt, having ideal formula Pb₂₈As₁₅S₅₀Cl.

NOMENCLATURE PROPOSALS APPROVED IN APRIL 2019

IMA 18-H: Redefinition of cadwaladerite and discreditation of lesukite

• Proposal 18-H is accepted, demonstrating that cadwaladerite and lesukite are the same mineral species. Because cadwaladerite has historical precedence, it is recognised as a valid mineral species, whereas lesukite is discredited. Furthermore, the formula of cadwaladerite is redefined as Al₅(H₂O)₃(OH)₁₂·n(Cl,H₂O).

IMA 18-K: Nomenclature and classification of the tetrahedrite group

• Proposal 18-K on the tetrahedrite group is accepted. The general structural formula of minerals belonging to this group is ^M(2)A₆ ^M(1)(B₄C₂)_Σ6 ^X(3)D₄ ^S(1)Y₁₂ ^S(2)Z (Z = 2), where A = Cu⁺, Ag⁺, ☐; B = Cu⁺, Ag⁺; C = Zn²⁺, Fe²⁺, Hg²⁺, Cd²⁺, Mn²⁺, Cu²⁺, Cu⁺, Fe³⁺; D = Sb³⁺, As³⁺, Bi³⁺, Te⁴⁺; Y = S^2-, Se^2-; and Z = S^2-, Se^2-, ☐. The tetrahedrite group is divided into five different series on the basis of the A, B, D, and Y constituents, i.e. the tetrahedrite, tennantite, freibergite, hakite, and giraudite series. The nature of the dominant C constituent is made explicit using a hyphenated suffix between parentheses. Eleven minerals belonging to the tetrahedrite group can be considered as valid species: argentotennantite-(Zn), argentotetrahedrite-(Fe), kenoargentotetrahedrite-(Fe), giraudite-(Zn), goldfieldite, hakite-(Hg), rozhdestvenskayaite-(Zn), tennantite-(Fe), tennantite-(Zn), tetrahedrite-(Fe), and tetrahedrite-(Zn). Furthermore, annivite is formally discredited.

IMA 19-B: Establishment of the calcioferrite group

• Proposal 19-B on the calcioferrite group is accepted. The general formula of minerals belonging to this group is Ca₄AB ₄(PO₄)₆(OH)₄·12H₂O, and two subgroups are defined on the basis of the dominant cation at the B site: the calcioferrite subgroup (B = Fe³⁺: calcioferrite, zodacite), and the montgomeryite subgroup (B = Al: montgomeryite, kingsmountite, fanfaniite). Aniyunwiyaite is discredited as being kingsmountite, which is assigned a triclinic structure with an ideal formula changed to Ca₃MnFeAl₄(PO₄)₆(OH)₄·12H₂O.

NOMENCLATURE PROPOSALS APPROVED IN MAY 2019

Application of the IMA-CNMNC dominant-valency rule to complex mineral compositions

• This is a special proposal, coauthored by all the officers of the CNMNC and approved by the members of the Commission itself. It is aimed at solving possible troubles in the definition of the ideal end-member formula of a mineral, which may be crucial for the definition of new mineral species. The IMA-CNMNC recommends the use of the dominant-valency rule for mineral nomenclature, because it alone may lead to unambiguous mineral identification. However, the simple application of the dominant-valency rule may sometimes result in unbalanced end-member formulae, due to the occurrence of a coupled heterovalent substitution at two sites along with a heterovalent substitution at a single site. In these cases, it is recommended to use the site total charge approach to identify the dominant root-charge arrangement on which the dominant-constituent rule can be applied.