Nuovi minerali 2009 approvati dall'IMA CNMNC in ottobre 2009

[Marco E. Ciriotti]

PROPOSALS APPROVED IN OCTOBER 2009

IMA No. 2009-050
Bonnet Island, Georgian Bay, Parry Sound, Ontario, Canada (UTM coordinates 0567531W 5003719N NAD 83)
Edward S. Grew
{(Y, REE)(Ca, Fe2+)2}[(Mg,Fe2+)(Fe3+,Al)]Si3O12; end member is (Y2Ca)(Mg2)Si3O12
Garnet group
Cubic: Ia-3d; structure determined
a 11.9947(6) Å

IMA No. 2009-051
Upper Chegem volcanic structure, Kabardino-Balkaria, North Caucasus, Russia (43°17'N 43°6.42'E)
Irina O. Galuskina
Ca3U6+ZrFe3+2Fe2+O12
Garnet group
Cubic: Ia-3d; structure determined
a 12.7456(9) Å

IMA No. 2009-052
Upper Chegem volcanic structure, Kabardino-Balkaria, North Caucasus, Russia (43°17'N 43°6'E)
Irina O. Galuskina
Ca3SbSnAl3O12
Garnet group
Cubic: Ia-3d; structure determined
a 12.492(1) Å

IMA No. 2009-053
Upper Chegem volcanic structure, Kabardino-Balkaria, North Caucasus, Russia (43°17'N 43°6.42'E)
Irina O. Galuskina
Ca3SbZrFe3O12
Garnet group
Cubic: Ia-3d; structure determined
a 12.49 Å

IMA No. 2009-054
Wiluy River, Yakutia, Russia (63.0oN 112.3o
Irina O. Galuskina E)
Ca3Sc2Si3O12
Garnet group
Cubic: Ia-3d; structure determined
a 12.255(1) Å

IMA No. 2009-055
Dúbrava Sb deposit, Low Tatra Mountains, Slovak Republic
Dan Topa
Pb15-2xSb14+2xS36Ox (x ~ 0.2)
New structure type
Monoclinic: C2/m; structure determined
a 48.189(48), b 4.1104(40), c 34.235(35) Å, β 106.059(15)°

IMA No. 2009-056
Nishny Tagil ultramafic complex, Solovyeva Gora, Alexandrov Log, Russia (57°40'N 59°39'W) and the Konder placer, Konder alkaline-ultrabasic massif, Maya River basin, South Yakutia, East Siberia, Russia (57°36'N 134°37'W)
Victor D. Begizov
(Fe,Rh,Ni,Ir,Cu,Pt)9S8
Possibly a distorted pentlandite derivative
Tetragonal: Primitive
a 10.009(5), c 9.840(8) Å

IMA No. 2009-057
Kobokobo pegmatite, Kobokobo, South Kivu Province, Democratic Republic of Congo (3º5'S 27º8'E)
Stuart J. Mills
Al6(PO4)4(OH)6∙11H2O
New structure type
Triclinic: P1 or P-1
a 7.399(13), b 7.771(17), c 12.144(16) Å, α 99.03(17), β 91.98(17), γ 116.11(15)º

IMA No. 2009-058
Lengenbach, Binn Valley, Switzerland
Fabrizio Nestola
Tl5-xPb2x(As,Sb)21-xS34
As-dominant analogue of chabournéite (x ~ 1)
Triclinic: P1 (by analogy with chabournéite)
a 16.217(7), b 42.544(9), c 8.557(4) Å, α 95.72(4), β 90.25(4), γ 96.78(4)º

IMA No. 2009-059
Liley, Üdersdorf, Daun, Eifel Mountains, Rheinland-Pfalz, Germany (holotype); Tausonitovaya Gorka, Murun alkaline complex, Irkutsk province, Russia (cotype)
Yulia Uvarova
NaKBaTi2(Si4O12)O2
K analogue of batisite
Orthorhombic: Imma; structure determined
a 8.0884(4), b 10.4970(5), c 13.9372(6) Å

IMA No. 2009-060
Prága Hill, Bazsi, Veszprém County, Transdanubia, Hungary (46°56'N 17°15'E)
Giovanna Vezzalini
(Mg0.7K0.5Ca0.5Na0.1)[Al3Si9O24]·10H2O
Mg-dominant chabazite
Rhombohedral: R-3; structure determined
a 9.3433(5) Å, α 94.894(4)º

IMA No. 2009-062
Tolbachik volcano, Kamchatka, Far-Eastern Region, Russia
Mikhail E. Zelenskiy
Cu3(VO4)2
Dimorph of triclinic mcbirneyite
Monoclinic: P21/c
a 6.2695(4), b 8.0195(3), c 6.3620(3) Å, β 111.96(1) º /с; structure determined

IMA No. 2009-063
Aga mine (35°16.4'N, 116°5.7'W) and the Bird Nest drift (35°16.6'N, 116°6.0'W), Otto Mountain, San Bernardino County, California, USA
Anthony R. Kampf
Pb2TeO5
New structure type
Monoclinic: Cc; structure determined
a 13.099(3), b 5.714(1), c 7.520(2) Å, β 123.80(3)º

IMA No. 2009-064
Aga mine (35°16.4'N, 116°5.7'W) and the Bird Nest drift (35°16.6'N, 116°6.0'W), Otto Mountain, San Bernardino County, California, USA
Anthony R. Kampf
Pb2Cu5(TeO6)2(OH)2
New structure type
Orthorhombic: P21nm
a 5.2000(2), b 9.6225(4), c 11.5340(5) Å nm; structure determined

IMA No. 2009-065
Aga mine (35°16.4'N, 116°5.7'W), Otto Mountain, San Bernardino County, California, USA
Anthony R. Kampf
Pb2Cu4(TeO6)2(H2O)2
New structure type
Orthorhombic: P212121
a 5.2006(5), b 9.6335(10), c 11.6837(13) Å ; structure determined


NOMENCLATURE PROPOSALS APPROVED IN OCTOBER 2009

09-A-bis STANDARDISATION OF MINERAL GROUP HIERARCHIES
Criteria for the definition of mineral groups, and a hierarchical scheme for the nomenclature of groups, have been set up. The latter has been applied to selected cases of existing groups, and will serve as a basis for a forthcoming compilation of mineral groups including as many minerals as possible.

NOMENCLATURE OF THE TOURMALINE GROUP MINERALS
Re-examination and redefinition of tourmaline end-members and potential new end-members and species has undertaken, including a classification guide for naming tourmalines.

PERTSEVITE IS RENAMED PERTSEVITE-(F)
A new mineral from the Snezhnoye deposit, Chersky Mountains, Republic of Sakha-Yakutia, Russian Federation (IMA 2008-060) has been approved by the CNMNC. Its formula is Mg2(BO3)(OH) and it is the OH-dominant analogue of pertsevite, Mg2(BO3)F. In voting comments on the name of the proposed new mineral (IMA 2008-060), six CNMNC members explicitly agreed in having pertsevite renamed as pertsevite-(F); only one member asked for an official decision by CNMNC. Accordingly, the Chair of CNMNC has authorised the renaming of pertsevite as pertsevite-(F) in order to standardise the nomenclature in the pertsevite group.

IMA 09-B DISCREDITATION OF PARASPURRITE, THE MONOCLINIC POLYMORPH OF SPURRITE
Paraspurrite is discredited. It corresponds to polysynthetically twinned spurrite.

IMA 09-C MOSANDRITE: REDEFINITION OF ITS COMPOSITION. RINKITE IS NO MORE QUESTIONABLE
Mosandrite is a mineral species belonging to the rinkite group and differing from rinkite in its chemical, crystallographic and structural features. The formula of mosandrite is redefined as Ti(□,Ca,Na)3(Ca,REE)4(Si2O7)2[H2O,OH,F]4·H2O. Rinkite is no more a questionable (Q) species, but a fully valid member, together with mosandrite and nacareniobsite-(Ce), of the rinkite group of minerals.

[Marco E. Ciriotti]

Alcuni commenti sulle copiose approvazioni (15 nuove specie) di ottobre 2009:

i) interessantissimo notare come alcune nuove località indagate di recente (Chegem, Aga mine, Bird Nest) siano portatrici di nuove specie di elevato contenuto chimico e strutturale (vedasi anche approvazioni dei mesi precedenti);

ii) altrettanto interessante riscontrare come, l'un dietro l'altro, si siano scoperti, un po' ovunque, nuovi granati, tra cui anche quello di scandio (IMA 2009-054) (vedasi anche approvazioni dei mesi precedenti);

iii) una nuova specie (IMA 2009-058) è stata scoperta tra i campioni trovati a Lengenbach da un collezionista italiano (vedasi più di un articolo che facevano presupporre la novità, pubblicati sulla Rivista Mineralogica Italiana);

iv) una nuova zeolite (IMA 2009-060: chabazite-Mg) è stata scoperta da ricercatori italiani in campioni ungheresi;

v) a livello nomenclaturale sono state approvate sia la standardizzazione delle gerarchie classificative (vedasi topic ad hoc), sia il riesame e la riclassificazione del gruppo delle tormaline (Report della Sottocommissione sulle Tormaline);

vi) finalmente il riconoscimento della mosandrite e della rinkite come due distinte valide specie minerali (eccellente lavoro di "accanimento mineralogico" dell'Università di Pisa);

vii) logica ridenominazione della "pertsevite" in pertsevite-(F), dopo la scoperta della nuova specie pertsevite-(OH) e discredito della paraspurrite (molte di queste specie "para" altro non sono, in realtà, che politipi o politipoidi);

vIII) la scoperta del dimorfo triclino della mcbirneyite (IMA 2009-062). Potrebbe essere presente tra le specie del "legnone" di Molinello?

[Marco E. Ciriotti]

Il nuovo granato di scandio (IMA 2009-054) era già stato brevemente descritto in precedenza.

Referenza:
• Galuskina, I.O., Galuskin, E.V., Dzierżanowski, P., Armbruster, Th., Kozanecki, M. (2005): A natural scandian garnet. American Mineralogist, 90, 1688-1692.

Abstract:
Garnet from an aposkarn achtarandite-bearing rodingite-like rock in Sakha-Yakutia, Russia, has a Sc content close to 6 wt% Sc2O3 (~0.45 apfu). The scandian garnet is a relict mineral from a high temperature, shallow-level melilite skarn. Structural and electron microprobe data for a crystal of the scandian garnet with cell parameter a = 12.331(1) Å, Ia-3d allows refinement of the structural formula (Ca2.97Mg0.02Y0.01)Σ3(Fe3+0.663Zr0.584Ti4+0.294Sc0.153Cr0.152Mg0.094Fe2+0.04Hf0.008V0.003)Σ3(Si1.898Al0.420Ti4+0.359Fe3+0.323)Σ3O12. Investigation of the composition of many of the scandian garnets reveals the existence of a solid-solution between kimzeyite-schorlomite Ca3(Zr,Ti)2(Al,Fe)2SiO12 and the scandium analog of andradite Ca3Sc2Si3O12. This is the first report of a natural scandian garnet.

Referenza:
• Oberti, R., Quartieri, S., Dalconi, M.C., Boscherini, F., Iezzi, G., Boiocchi, M., Eeckhout, S.G. (2006): Site preference and local geometry of Sc in garnets: Part I. Multifarious mechanisms in the pyrope-grossular join. American Mineralogist, 91, 1230-1239.

Abstract:
We applied different independent techniques (electron microprobe analysis, structure refinement, and X-ray absorption spectroscopy) to unravel the possible mechanisms of Sc incorporation in the pyrope-grossular join. Samples were synthesized at elevated pressure and temperature by adding 5 wt% of Sc2O3 to selected nominal compositions (pyrope, pyrope60grossular40, pyrope20grossular80, and grossular). In this way, the site of incorporation was not pre-determined, and only depends on the availability of a mechanism for local charge-balance. The EXAFS spectra of the two end-members could be analyzed by a multi-shell fit procedure, whereas the chemical heterogeneity of the Sc-doped solid-solution terms prevented this approach. However, the available information allows detection of different mechanisms of incorporation, which are active as a function of the bulk composition. In pyrope, Sc mainly enters the dodecahedral X site, and the local charge balance is achieved by incorporation of Mg at the adjacent tetrahedral Z site. Local charge-balance requirements suggest that a Z site occupied by Mg bridges two X sites occupied by Sc. When the entrance of Ca provides relaxation of the averaged structure, Sc may enter all the three available cation sites via the coupled heterovalent exchange XSc1ZSc1XMg–1ZSi–1 and the homovalent exchange YSc1YAl–1. In the samples of this work, there is an apparent limit in the Sc incorporation at the Y site, which is in contrast to the favored mechanism of incorporation in Sc-doped andradites. This limit can be explained in terms of relative dimensions of the structural sites when Al is the dominant Y cation. These results must be taken into account when evaluating trace-element behavior in garnets for geochemical purposes. In particular, they explain why DSc can be treated together with DREE in models based on the elastic strain theory in garnets close to the pyrope composition, but deviate from the parabolic fit in grossular-rich garnets.

Referenza:
• Quartieri, S., Oberti, R., Boiocchi, M., Dalconi, M.C., Boscherini, F., Safonova, O., and Alan B. Woodland, A.B. (2006): Site preference and local geometry of Sc in garnets: Part II. The crystal-chemistry of octahedral Sc in the andradite–Ca3Sc2Si3O12 join. American Mineralogist, 91, 1240-1248.

Abstract:
Investigation of scandium incorporation in garnets along the synthetic Ca3Fe3+2 Si3O12–Ca3Sc2Si3O12 (adr–CaSc) join, based on the same multi-technique approach used in the companion paper (Oberti et al. 2006a), shows that (1) Sc is incorporated exclusively at the Y octahedron; (2) the local coordination of Sc is slightly different in Sc-poor than in Sc-rich compositions (Sc-O = 2.06 Å in CaSc10 vs. 2.10 Å in CaSc30–90); (3) the local coordination of Ca is also slightly different in Sc-poor than in Sc-rich compositions [Ca1,2-O are 2.34(2) and 2.48(2) Å in CaSc10 and 2.36(2) and 2.50(2) Å in CaSc90, with fixed at 0.14 Å in all the samples]; (4) the linear increase of the unit-cell edge along the join derives from multiple changes in the geometry of the different polyhedra and from the rotation of the tetrahedron around the axis ( rotation), and cannot be modeled from extrapolation of the behavior observed along the Ca3Al2Si3O12–Ca3Fe3+2 Si3O12 (grs–adr) join.
CaSc-rich garnets, where a large X dodecahedron coexists with a large Y octahedron and a Z tetrahedron occupied by Si, similar to pyrope-grossular garnets, have the highest values observed to date in calcium silicate garnets. Slightly lower values are observed in pyrope and almandine, but correspond to a different structural arrangement, where a small X dodecahedron coexists with a small Y octahedron. These results further confirm the efficiency of a combined short- and long-range approach for understanding the properties of garnet solid solutions.

[Roberto Bracco]

vIII) la scoperta del dimorfo triclino della mcbirneyite (IMA 2009-062). Potrebbe essere presente tra le specie del "legnone" di Molinello?

Ci starebbe come il cacio sui maccheroni... ma sarei contento di portare avanti quello che già abbiamo!

[Marco E. Ciriotti]

Certo sì, Roberto. Faccio un sollecito un po' pressante.

IMA No. 2009-059
Liley, Üdersdorf, Daun, Eifel Mountains, Rheinland-Pfalz, Germany (holotype); Tausonitovaya Gorka, Murun alkaline complex, Irkutsk province, Russia (cotype)
Yulia Uvarova
NaKBaTi2(Si4O12)O2
K analogue of batisite
Orthorhombic: Imma; structure determined
a 8.0884(4), b 10.4970(5), c 13.9372(6) Å

La formula è più in linea con gli altri membri del gruppo se "strutturalmente" scritta : NaKBaTi2O[Si2O6]2.

Questo nuovo minerale è stato in precedenza abbastanza ben descritto e la sua struttura risolta con il nome - ora discreditato(?) - di "noonkanbahite".

Referenze:
• Prider, R.T. (1965): Noonkanbahite, a potassic batisite from the lamproites of Western Australia. Mineralogical Magazine, 34, 403-405.
• Rastsvetaeva, R.K., Pushcharovsky, D.Yu., Konev, A.A., Evsyunin, V.G. (1997): Kristallografiya, 42, 837-840.
• Uvarova, Y.A., Sokolova, E., Hawthorne, F.C., Liferovich, R.P., Mitchell, R.H. (2003): The crystal structure of shcherbakovite from the Khibina Massif, Kola Peninsula, Russia. Canadian Mineralogist, 41, 1193-1201.

Di quest'ultima, ecco l'abstract:
The crystal structure of shcherbakovite from Mount Rasvumchorr, Khibina massif, Kola Peninsula, Russia, ideally K2 Na Ti24+ O (OH) [Si4O12], a 8.1538(4), b 10.5569(5), c 13.9882(6) Å, V 1204.1(2) Å3, space group Imma, Z = 4, Dcalc 3.194 g/cm3, has been refined to R1 = 3.2% for 960 unique (Fo > 4F) reflections collected on a Bruker single-crystal P4 diffractometer equipped with a CCD detector and MoK X-radiation. Shcherbakovite occurs in late (hydrothermal) shallowly dipping veins of natrolite and is associated with natrolite, aegirine, K-feldspar, strontian apatite, titanite, spherulitic baryllite and rare pyrrhotite and chalcopyrite. Electron-microprobe analysis gave SiO2 40.57, TiO2 18.87, Fe2O3 1.05, MnO 0.06, BaO 6.7, CaO 0.20, K2O 13.22, Na2O 5.59, Nb2O5 10.49, SrO 0.08, ZrO2 0.84, Ta2O5 0.06, (H2O)calc 0.73, sum 97.83 wt.%. The amount of H2O was determined from crystal-structure analysis. There is one tetrahedrally coordinated T site, <T–O> 1.607 Å, occupied by Si. There are two octahedrally coordinated sites, M(1), occupied by (Ti0.68 Nb0.32 1.00), with <M(1)–O> = 2.016 Å, and M(2), occupied by (Ti0.72 Nb0.15 Fe0.083+ Zr0.04 1.01), with <M(2)–O> = 1.999 Å. The M(1) and M(2) sites are separated by 0.477 Å, and hence cannot be occupied simultaneously at a local level. There are three interstitial A sites: the A(1) site is [9]-coordinated and is occupied by (K0.66 Ba0.23 Na0.07 Ca0.02), with <A(1)–O> = 2.952 Å; the A(2) site is [8]-coordinated and is occupied by K, with <A(2)–O> = 2.861 Å, and the A(3) site is [6]-coordinated and is occupied by Na, with <A(3)–O> = 2.493 Å. Shcherbakovite is a K-analogue of batisite, ideally Ba Na2 Ti24+ O2 [Si4O12]. Shcherbakovite is related to batisite by substitution of K for Ba and K for Na. "Noonkanbahite", ideally Ba K Na Ti24+ O2 [Si4O12], has never been approved by the IMA as a new mineral species. Based on the crystal chemistry of this structure type, the general formula of these minerals may be written as A B C M2 2 [Si4O12], with the following end-member compositions: batisite A = Ba, B = Na, C = Na; shcherbakovite, A = K, B = K, C = Na; "noonkanbahite", A = Ba, B = K, C = Na; unnamed, A = K, B = Na, C = Na.

[Antonio Borrelli]

La rinkite ora torna a status di grandfathered?

[Marco E. Ciriotti]

No, redefined (and reclassified).

[Marco E. Ciriotti]

Relativamente a IMA 2009-050.

Referenza:
• Grew, E.S., Marsh, J.H., Yates, M.G., Lazic, B., Armbruster, T., Locock, A., Bernhardt, H.J., Medenbach, O. (2009): A new yttrium garnet species {(Y,REE)(Ca,Fe2+)2}[(MG,Fe2+)(Fe3+,Al)](Si3)O12, and two components in metamorphic garnet: {Y2Ca}[Mg2](Si3)O12 and {Y2Ca}[Fe2+2](Si3)O12. 2009 Portland GSA Annual Meeting (18-21 October 2009), Geological Society of America Abstracts with Programs, 41, 358,

Abstract:
new yttrium garnet (IMA 2009-050, submitted) forms reddish-brown cores (n = 1.844) up to 75 µm across rimmed by euhedral almandine-grossular (Alm59Grs18Prp9Adr5Sps4other5; < 2 wt% Y2O3) in a pyroxene-plagioclase granulite on Bonnet Island in the interior Parry Sound domain, Central Gneiss Belt, Grenville Orogenic Province, Canada. A representative analysis gave {Y0.83Gd0.01Dy0.05Ho0.02Er0.07Tm0.01Yb0.06Lu0.02Ca1.37Fe2+0.49Mn0.07}[Mg0.55Fe2+0.42Fe3+0.58Al0.35V0.01Sc0.01Ti0.08](Si2.82Al0.18)O12, corresponding in mole% (rare earth elements combined with Y) to 6.0 {Y3}[Al2](Al3)O12 (YAG), 27.3 {Y2Ca}[Mg2](Si3)O12 (YMg), 17.3 {Y2Ca}[Fe2+2](Si3)O12 (YFe), 9.2 Alm, 21.9 Adr, 7.6 {Ca3}[TiFe2+](Si3)O12, 7.1 {Fe2+3}[Fe3+2](Si3)O12, and 3.6 other. Single crystal study gave space group Ia-3d, a = 11.9947(6) Å and Mg occupying the octahedral site. Contacts of the new garnet with Alm-Grs are sharp and irregular, showing cusps and embayments. Traverses across the new mineral commonly gave increases in Y, Mg and Ti, but never in Yb, from core to the contact with enclosing Alm-Grs. Y content of the enclosing Alm-Grs decreases towards its rim except for a small increase right near the contact with the new garnet. The new garnet also contacts K-feldspar, allanite-(Ce) (Aln~70-85) and apatite, but prior to growth of Alm-Grs it presumably equilibrated also with ferrosilite (Fs56-60En41-37Wo~1 plus ~1%MnSiO3), oligoclase (An27), magnetite, ilmenite and possibly augite during the first stage of metamorphism estimated to be at T ≥ 830 °C, P ≈ 11 kbar. The second stage assemblage included augite, ferropargasite and Alm-Grs + Qtz ± Cpx symplectite. Until now the components YAG and its Fe3+ analogue YIG, {Y3}[Fe3+2](Fe3+3)O12, were the only two recognized substitutions in addition to Na + (Y, REE) = 2Ca in metamorphic garnet. Incorporation of Y + REE via the YMg and YFe components can be related to YAG and YIG by equations of the type 3YMg + 5Al2O3 = 2YAG + 3Di + 3En, suggesting YMg and YFe incorporation would be favored in intermediate and mafic rocks, whereas YAG and YIG incorporation would be favored in pelitic and highly oxidized rocks, respectively. Variation of Si with (Y + REE – Na) reported in the literature can be explained by incorporation of YAG or YIG only or by a combination of YAG/YIG with YMg/YFe.