In 2014, the IMA introduced its “Mineral of the Year” initiative, aimed to recognize the most inspiring and exciting mineral discoveries published in a given calendar year. With this initiative, the IMA likes also to acknowledge the Commission on New Minerals, Nomenclature and Classification (CNMNC) for their tireless work. It is never easy choosing the winner and we are happy to announce the finalists in the category “Mineral of the Year 2019”:

The prestigious title went to “Tewite” that was discovered in the vicinity of Nanyang village, Huaping County, located in the south of the Panzhihua–Xichang region, southwestern China. It occurs in the Neoproterozoic Sinian light-weathered biotite–quartz monzonite, near the contact zone with gabbro. The associated minerals are alkali feldspar, biotite, clinoamphibole, ilmenite, zircon, zoisite, tourmaline, monazite-(Ce), allanite-(Ce), scheelite, tellurite and the new mineral wumuite (KAl_0.33W_2.67O₉, IMA2017-067a), in addition to an unidentified, potentially new mineral corresponding to WO₃.
Tewite forms platy crystals that range from 0.08×0.1×0.1 to 0.1×0.2×0.5 mm in size. The crystals are greenish yellow, with a light-yellow to white streak, translucent to transparent, and with adamantine luster. Mohs hardness is 3½–4, and the tenacity is brittle. Tewite has perfect {100}, {001}, and {010} cleavages. The empirical formula, based on 19 O, is (K_1.61Na_0.06□_0.33)_∑2.00(Te_1.06W_0.35□_0.59)_∑2.00W₅O₁₉. Already first studies showed tewite to be a new mineral with a new crystal-structure type and a composition containing Te, W and K. No similar minerals or synthetic compounds corresponding to this mineral have been previously found.
Tewite has a new tungsten-bronze (TB)-type derivative structure. Distorted TeO6 octahedra break TB slabs into ribbons which are displaced by ½ a relative to their neighbors, while K partly occupies two mutually exclusive sites in hexagonal channels || c. Short-range order and displacement of K ions are likely responsible for an observed incommensurate modulation of the average structure indicated by weak satellite reflections along c*, which were not considered in the structure refinement.
The two closest runners-up were Rudabanyaite, a new mineral with a [Ag₂Hg₂]⁴⁺ cluster cation from the Rudabánya ore deposit (Hungary) described by Herta Effenberger and co-authors (2019) in the European Journal of Mineralogy and Davidbrownite-(NH₄), a new phosphate–oxalate mineral from the Rowley mine, Arizona, USA, described by Anthony R. Kampf and co-authors in the Mineralogical Magazine (2019).

We would like to congratulate Guowu Li and co-authors on the discovery of tewite and encourage all colleagues to read about this fantastic find in the European Journal of Mineralogy article.

 

REFERENCES

Li, Guowu, Xue, Yuan, Xiong, Ming (2019): Tewite: A K–Te–W new mineral species with a modified tungsten-bronze type structure, from the Panzhihua-Xichang region, southwest China. European Journal of Mineralogy 31 (1):145–152.
https://doi.org/10.1127/ejm/2019/0031-2813

Effenberger, H., Szakáll, S., Fehér, B., Váczi, T.; Zajzon, N. (2019): Rudabányaite, a new mineral with a [Ag₂Hg₂]⁴⁺ cluster cation from the Rudabánya ore deposit (Hungary).
European Journal of Mineralogy 31 (3):537–547.
https://doi.org/10.1127/ejm/2019/0031-2830

Kampf, A.R., Cooper, M.A., Rossman, G.R., Nash, B.P., Hawthorne, F.C., Marty, J. (2019): Davidbrownite-(NH₄), (NH₄,K)₅(V⁴⁺O)₂(C₂O₄)[PO_2.75(OH)_1.25]₄·3H₂O, a new phosphate–oxalate mineral from the Rowley mine, Arizona, USA. Mineralogical Magazine 83 (6):869-877.
https://doi.org/10.1180/mgm.2019.56

At long last and after much deliberation, the IMA Commission on New Minerals, Nomenclature and Classification is pleased to announce its chosen Mineral of the Year 2018. The “race” was tight and there were many worthy contenders, but the winner is a true gem (or at least, was presented as such in the media). The new complex oxide carmeltazite (ZrAl₂Ti₄O₁₁) forms black inclusions in blue corundum crystals (“Carmel SapphireTM”) from Cretaceous pyroclastic rocks and associated alluvial deposits at Kishon Mid-Reach in northern Israel. Its name alludes to the type locality at Mt. Carmel and the three principal metals in its formula (Ti, Al and Zr). Carmeltazite was discovered by William L. Griffin (Macquarie University, Australia), Sarah E.M. Gain (University of Western Australia), Luca Bindi (Università degli Studi di Firenze, Italy), Vered Toledo (Shefa Gems Ltd., Israel), Fernando Cámara (Università degli Studi di Milano, Italy), Martin Saunders (University of Western Australia), and Suzanne Y. O’Reilly (Macquarie University). Since its description was published in Minerals (Griffin et al., 2018), the mineral has gained much publicity online as “the world’s newest gemstone” (EraGem, 2019), and even an “extraterrestrial mineral harder than diamonds” (Flatley, 2019). Although perfectly terrestrial in origin and not particularly gemmy, the Mineral of the Year 2018 does contain Ti3+, altogether rare in the geological environment, and possesses a peculiar crystal structure, which is remotely related to the close-packed arrangement of spinel. As can be seen from its formula, the structure of carmeltazite is cation- and anion-deficient relative to spinels, while its symmetry is reduced to orthorhombic. Perhaps even more remarkable than its public image or structure is the association of carmeltazite with other Ti3+ and carbide minerals, which indicates very unusual geological conditions in their volcanic cradle and promises new exciting discoveries in the future (Griffin et al., 2018).

We would also like to acknowledge here the close runners-up, which included the modular carbonato-phosphato-silicate aravaite from pyrometamorphic rocks of the Hatrurim Complex in Israel (Krüger et al., 2018) and the first-ever tin sulfate genplesite from the Oktyabr'skoe Cu-Ni-Pd-Pt deposit in Siberia, Russia (Pekov et al., 2018). Once again, we congratulate Bill Griffin and his co-authors on their interesting discovery.

REFERENCES
EraGem (2019) Carmeltazite the world’s newest gemstone (https://eragem.com/news/)
Griffin WL, Gain SEM, Bindi L, Toledo V, Cámara F, Saunders M, O’Reilly SY (2018) Carmeltazite, ZrAl₂Ti₄O₁₁, a new mineral trapped in corundum from volcanic rocks of Mt Carmel, northern Israel. Minerals 8:601 (https://www.mdpi.com/2075-163X/8/12/601)
Flatley H (2019) Extraterrestrial mineral harder than diamonds discovered in Israel (https://www.thevintagenews.com/2019/01/15/carmel-sapphire)
Krüger B, Krüger H, Galuskin EV, Galuskina IO, Vapnik Y, Olieric V, Pauluhn A (2018) Aravaite, Ba₂Ca₁₈(SiO₄)₆(PO₄)₃(CO₃)F₃O: modular structure and disorder of a new mineral with single and triple antiperovskite layers. Acta Crystallographica B 74: 492-501
Pekov IV, Sereda EV, Zubkova NV, Yapaskurt VO, Chukanov NV, Britvin SN, Lykova IS, Pushcharovsky DY (2018) Genplesite, Ca₃Sn(SO₄)₂(OH)₆∙3H₂O, a new mineral of the fleischerite group: first occurrence of a tin sulfate in nature. European Journal of Mineralogy 30: 375-382

In 2014, the IMA introduced its “Mineral of the Year” initiative, aimed to recognize the most inspiring and exciting mineral discoveries published in a given calendar year, and to acknowledge the Commission on New Minerals, Nomenclature and Classification (CNMNC) for their tireless work. Over 100 new mineral species are approved by the Commission every year from an even greater number of proposals sent in from around the globe. Choosing the winner is never easy and always extra work for the CNMNC expert panel. We applaud them for their dedication and are happy to announce the finalists in the category “Mineral of the Year 2017”.

The prestigious title went to black cuboctahedral crystals peppering green mottramite in an underground tunnel at the abandoned Rowley mine in Arizona, and named for the type locality ROWLEYITE. The chemical formula of this new species is as complex as its crystal structure, and both are a testament to the capabilities of modern science and to the uniqueness of geological conditions that led to rowleyite crystallization. Although structurally related compounds are known in materials science as “salt-templated mesoporous solids” and “polyoxometalates”, it is difficult to succinctly identify something that has the formula [Na(NH₄,K)₉Cl₄][V₂^5+,4+(P,As)O₈]₆·n[H₂O, Na,NH₄,K,Cl]. Rowleyite can be described as a phosphovanadate with a zeolite-like, porous framework, in which small cages host the [(NH₄,K)₉Cl₄]⁵⁺ clusters forming a “salt net” and large cages accommodate H₂O, NH₄, Na, K and Cl. This paragon of mineralogical complexity was discovered and published in American Mineralogist (volume 102, pages 1037-1044) by Anthony R. Kampf (Natural History Museum of Los Angeles County, USA), Mark A. Cooper (University of Manitoba, Canada), Barbara P. Nash and Thure E. Cerling (University of Utah, USA), Joe Marty (Salt Lake City, Utah), Daniel R. Hummer (Southern Illinois University, USA), Aaron J. Celestian (Natural History Museum of Los Angeles County), Timothy P. Rose (Lawrence Livermore National Laboratory, USA), and Thomas J. Trebisky (University of Arizona, USA). Congratulations to the winning team on this exciting discovery!

The two closest runners-up were kegginite (another polyoxovanadate from the Packrat mine in Colorado, described by Anthony R. Kampf and colleagues (2017) in American Mineralogist and the Ti³⁺-dominant garnet rubinite discovered in the Vigarano, Allende and Efremovka carbonaceous chondrites by Chi Ma et al. (2017).

REFERENCES
Kampf AR, Cooper MA, Nash BP, Cerling TE, Marty J, Hummer DR, Celestian AJ, Rose TP, Trebisky TJ (2017) Rowleyite, [Na(NH4,K)₉Cl₄][V^5+,4+₂(P,As)O₈]₆·n[H₂O,Na,NH₄,K, Cl][Na(NH₄,K)₉Cl₄][V₂^5+,4+(P,As)O₈]·n[H₂O,Na,NH₄,K,Cl]⁠, a new mineral with a microporous framework structure. American Mineralogist 102: 1037-1044 ₆
Kampf AR, Hughes JM, Nash BP, Marty J (2017) Kegginite, Pb₃Ca₃[AsV₁₂O₄0(VO)]·20H₂O, a new mineral with a novel ε-isomer of the Keggin anion. American Mineralogist 102: 461-465
Ma C, Yoshizaki T, Krot AN, Beckett JR, Nakamura T, Nagashima K, Muto J, Ivanova MA (2017) Discovery of rubinite, Ca₃Ti³⁺₂Si₃O₁₂, a new garnet mineral in refractory inclusions from carbonaceous chondrites. 80th Annual Meeting of the Meteoritical Society 2017 (LPI Contrib. No. 1987), 6023.pdf