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Two new minerals, zhenruite, ideally (MoO.sub.3).sub.2 âH.sub.2 O, and tianhuixinite, ideally (MoO.sub.3).sub.3 âH.sub.2 O, were discovered, respectively, from the Freedom #2 mine in the central part of the Marysvale volcanic field, Utah, USA, and an unnamed short adit on the Summit group of claims near Cookes Peak, Luna County, New Mexico, USA. Zhenruite occurs as acicular or prismatic crystals (up to 0.06x0.01x0.01 mm). Associated minerals include alunogen, anhydrite, coquimbite, fluorite, liangjunite, quartz, and raydemarkite. Zhenruite is colorless in transmitted light and transparent with a white streak and vitreous luster. It is brittle with a Mohs hardness of 1 1/2-2; cleavage is perfect on 001. The calculated density is 4.081 g cm.sup.-3 . Tianhuixinite occurs as nanometric crystal aggregates, 10-70 µm in size, intergrown with virgilluethite. Associated minerals include barite, fluorite, ilsemannite, jordisite, powellite, pyrite, quartz, raydemarkite, sidwillite, and virgilluethite. Tianhuixinite is dark blue-green and translucent in transmitted light. It has a white streak and vitreous luster. Tianhuixinite is brittle with a Mohs hardness of â¼2; no cleavage was observed. The calculated density is 4.131 g cm.sup.-3 . At room temperature, neither zhenruite nor tianhuixinite is soluble in water or hydrochloric acid. Electron microprobe analyses yielded an empirical formula (Mo.sub.1.00 O.sub.3).sub.2 âH.sub.2 O for zhenruite and (Mo.sub.1.00 O.sub.3).sub.3 âH.sub.2 O for tianhuixinite, calculated on the basis of 7 and 10 O apfu, respectively. Zhenruite and tianhuixinite are the natural counterparts of synthetic (MoO.sub.3).sub.2 âH.sub.2 O and hexagonal (MoO.sub.3).sub.3 âH.sub.2 O, respectively. Zhenruite is monoclinic with space group P21/m and unit-cell parameters a=9.6790(6), b=3.70653(19), c=7.1029(4) Ã, β=102.391(5)°, V=248.89(2) Ã.sup.3, and Z=2. Its crystal structure is characterized by two kinds of topologically identical octahedral double chains extending along [010], one consisting of edge-sharing Mo1O.sub.6 octahedra only and the other Mo2O.sub.5 (H.sub.2 O) octahedra only. These two kinds of chains are linked together alternately through sharing corners to form layers parallel to (001), which are interconnected by hydrogen bands along [001]. Tianhuixinite is hexagonal with space group P63/m and unit-cell parameters a=10.5963(12), c=3.7216(4) Ã, V=361.88(9) Ã.sup.3, and Z=2. Its crystal structure is composed of double chains of edge-sharing MoO.sub.6 octahedra extending along [001], which are corner-connected with one another to form hexagonal channels with H.sub.2 O residing at the center. The double chains of edge-sharing MoO.sub.6 octahedra in zhenruite and tianhuixinite are topologically identical to those in molybdite and raydemarkite, and zhenruite can be regarded as a combination of molybdite and raydemarkite both structurally and chemically. The discovery of tianhuixinite implies the likelihood of finding the ammonia analogue, (MoO.sub.3).sub.3 âNH.sub.3, in nature.

Friisite, ideally Pb.sub.8 Al.sub.3 Si.sub.8 O.sub.27 Cl.sub.3, is a new mineral discovered in a museum sample from the Långban mine in Värmland, Sweden. It occurs as subhedral, flaky grains up to 150 µm in size, forming aggregates within a medium-grained skarn matrix and contiguous to jagoite. Both are associated with melanotekite, aegirine-augite, albite, baryte, fluorapophyllite-K, margarosanite, alamosite, native lead, a serpentine group mineral, and a wickenburgite-like mineral. Friisite is white to colorless with a white streak and sub-adamantine luster. The mineral is transparent and does not fluoresce under UV light. It is brittle, with an uneven fracture and perfect cleavage on 001. Mohs hardness is 4-5 (by analogy with jagoite). The calculated density is 5.54(1) g cm.sup.-3 . Optically, friisite is non-pleochroic and uniaxial (-). Point analyses by means of an electron microprobe using wavelength-dispersive spectroscopy resulted in an empirical formula (based on 30 O+Cl): (Pb7.89Na0.11Ca0.08)â=8.08(Al2.19Si0.31Fe0.203+Zn0.13Mn0.112+)â=2.94Si8O27.02Cl2.98. Friisite is hexagonal, P6-2c (#190), with unit-cell parameters a=8.5955(1) Ã, c=23.4092(2) Ã, and V=1497.82(4) Ã.sup.3 for Z=2. The eight strongest powder X-ray diffraction lines are [d, à (I.sub.rel) (hkl)]: 5.848 (31) (004), 5.375 (20) (103), 4.040 (96) (11-2, 112), 3.680 (40) (201), 3.463 (100) (114), 2.886 (21) (116), 2.795 (20) (21-1), and 2.4828 (35) (300). Friiste is a phyllosilicate and forms a polysomatic series with jagoite characterized by a layer sequence of SiO.sub.4 tetrahedra (T) and metal octahedra (O) between double layers (*) corresponding to *TOT*, whereas jagoite is described as *TOTOT*. Friisite forms from transformation of melanotekite or barysilite in the presence of albite and a Cl-enriched fluid at relatively high aSiO2. The mineral (IMA2024-047) is named in honor of Danish mineralogist Henrik Friis (b. 1977), professor at the Natural History Museum, University of Oslo, Norway.

Spaltiite is a new thallium sulfosalt with the ideal formula of Tl.sub.2 Cu.sub.2 As.sub.2 S.sub.5 . It was found on a dump of the famous mineral locality Lengenbach (Binntal, Canton Valais, Switzerland). A small piece of pure white Triassic dolomite belonging to the Penninic Monte Leone Nappe hosts three euhedral long prismatic to lath-like spaltiite crystals, each approximately 2 mm in length but only â¼0.2 mm thin. The hand specimen contains small quantities of pyrite, drechslerite and hatchite. The spaltiite crystals are greyish to black in colour and extremely soft. The Mohs' hardness is 1.5-2 (VHN.sub.15 ranges from 30 to 65, mean 47 kg mm.sup.-2). The mono-clinic crystals have a perfect cleavage parallel to 100, which produces minute and plastic slabs. Reflectance measurements in air yield the following Rmin/Rmax values based on the standard wavelengths (Commission on Ore Mineralogy, COM): 27.0 % / 32.6 % (470 nm); 26.8 % / 32.1 % (546 nm); 26.0 % / 31.1 % (589 nm); and 24.8 % / 29.3 % (650 nm). Averaged electron-microprobe analyses (n=10) gave (in wt %) Tl 47.41(19), Cu 15.46(12), Ag 0.15(6), As 17.36(14), Sb 0.41(5) and S 19.20(8), total 99.99(32). The empirical formula is Tl.sub.1.94 Cu.sub.2.04 Ag.sub.0.01 As.sub.1.95 Sb.sub.0.03 S.sub.5.03, calculated based on 11 apfu. The large crystals exhibit a remarkably homogeneous composition. Spaltiite crystallises in space group P21/c (a=15.791(8), b=10.000(5), c=6.323(3) Ã, β=99.25(8)°, V=985.5(8) Ã.sup.3). The crystal structure was determined from single-crystal X-ray diffraction data (R.sub.1 =12.18 % for 4753 data, with F.sub.o >4Ï (F.sub.o) and 101 variable parameters). Spaltiite exhibits a pronounced layered atomic arrangement: two polar Cu-As layers in (1/4 y z) and (3/4 y z), respectively, are related by inversion symmetry. Sandwiched between them are the Tl atoms. These two layers are centred in (0 y z) and (1/2 y z), centrosymmetric but topologically and crystallographically distinct. The eight strongest intensities in the X-ray powder diagram are [d in à (intensity) hkl]: 3.914 (40) 021; 2.988 (63) 510; 3.496 (45) 311; 2.869 (45) 5-11; 2.652 (36) 3-31; 3.646 (34) 2-21; 2.506 (29) 040; 2.762 (26) 202. The name of the new mineral originates from the nickname \"spalti\", which was used during laboratory studies, illustrating the extremely pronounced cleavage (in German, \"spalten\" means cleave).

Keutschite, Cu.sub.2 AgAsS.sub.4, is a new mineral from the Ag-Pb-Zn deposit at Uchucchacua, Oyon District, Catajambo, Lima Department, Peru. The mineral occurs as metallic, highly lustrous, blocky, free-standing crystals measuring up to 3 mm. These crystals exhibit a grey colour with a slight green-brassy tint and a grey-black streak, and they are present on both manganoquadratite and proustite. It was observed that keutschite was brittle, and no fractures or cleavages were identified. In plane-polarised light, keutschite exhibits a grey hue devoid of any discernible internal reflections. It demonstrates a minimal manifestation of pleochroism and exhibits a negligible degree of bireflectance. Between crossed polars, the mineral is weakly anisotropic with rotation tints in shades of greenish grey to grey. Reflectance measurements in air yield the following Rmin/Rmax values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association: 25.2/26.1 (470 nm), 29.6/29.4 (546 nm), 29.4/29.2 (589 nm), and 28.5/28.6 (650 nm). Keutschite crystallises in a tetragonal geometry and is classified as space group I4-2m. The unit cell parameters are as follows: a=5.5834(15), c=10.021(3) Ã, V=312.40(14) Ã.sup.3, a:b:c=1:1:0.897, and Z=2. The crystal structure was refined to R.sub.1 =0.0199 for 286 reflections with I3Ï(I). The structure of keutschite is derived from that of sphalerite by ordered substitution of Zn atoms, analogous to the substitution pattern for deriving stannite from sphalerite. The crystal structure of the mineral can be derived from that of luzonite through the complete substitution of one of the two copper sites with silver. The five strongest intensities in the X-ray powder diagram are [d in à (intensity) hkl]: 3.101 (100) 110; 2.792 (11) 200; 1.974 (20) 220; 1.665 (34) 204; and 2.846 (27) 312. The chemical formula, as determined by electron microprobe analysis, is Cu.sub.2.05 Ag.sub.0.96 (As.sub.0.95 Sb.sub.0.04).sub.Σ0.99 S.sub.4.00 (based on eight atoms). The ideal formula, derived from the crystal structure, is Cu.sub.2 AgAsS.sub.4 . The name honours Frank Keutsch (born 1971) for his contribution to the mineralogy of the Uchucchacua deposit.

Suenoite (IMA 2019-075), ideally â¡Mn.sub.2 Mg.sub.5 Si.sub.8 O.sub.22 (OH).sub.2, is a new member of the amphibole supergroup discovered in the Mn ore deposit of Scortico-Ravazzone, Apuan Alps, Tuscany, Italy. It occurs as colourless tabular striated crystals, up to 0.1 mm in length, associated with spessartine and baryte. The streak is white, and the lustre is vitreous. Mohs hardness is estimated between 5.5 and 6. Cleavage is perfect on 210. The calculated density is 3.283 g cm.sup.-3 . Suenoite is optically biaxial (+), with α=1.655(5), β=1.660(5), and γ=1.670(5) (in white light). 2V.sub.meas is 75(10)°, and 2V.sub.calc is 70.9°. The orientation is X=a, Y=b, and Z=c. Pleochroism was not observed, as suenoite is colourless. The empirical chemical formula of suenoite is .sup.A (â¡.sub.0.91 Ca.sub.0.07 Na.sub.0.02).sub.Σ1.00 .sup.B (Mn1.642+Fe0.362+)Σ2.00 .sup.C (Mg.sub.3.56 Fe0.912+Mn0.612+Zn.sub.0.02).sub.Σ5.10 .sup.T (Si.sub.7.86 Al.sub.0.06).sub.Σ7.92 O.sub.22 .sup.W [(OH).sub.1.92 F.sub.0.08 ].sub.Σ2.00, and it is based on electron microprobe analyses, infrared spectroscopy, and Mössbauer spectroscopy. The unit-cell parameters of suenoite are a=18.7508(12), b=18.1396(12), c=5.3173(3) Ã, and V=1808.6(2) Ã.sup.3, with space group Pnma. The crystal structure was refined to R.sub.1 =0.0490 for 2236 unique reflections with F4ÏF and 194 refined parameters. The origin of suenoite is probably related to the recrystallisation of the Scortico-Ravazzone Mn ore deposit during the Tertiary tectono-metamorphic events, under greenschist-facies conditions, affecting the rocks belonging to the Alpi Apuane metamorphic complex.

Marioantofilliite (IMA 2025-012), ideally [Cu.sub.4 Al.sub.2 (OH).sub.12 ](CO.sub.3 )â 3H.sub.2 O, is a new member of the hydrotalcite supergroup discovered in the Cu-Fe ore deposit of Monte Copello-Reppia, Graveglia Valley, Liguria, Italy. It occurs as globular aggregates up to 1 mm in diameter formed by µm-sized prismatic crystals. The streak is light blue, and lustre is greasy. Calculated density is 2.825 g cm.sup.-3 . Marioantofilliite is optically biaxial (-), with α=1.613(4), β=1.626(3), and γ=1.633(5) (in 589 nm light). 2V.sub.calc is 72°. It is distinctly pleochroic, ranging from colourless to pale blue. The empirical chemical formula of marioantofilliite (with rounding errors) is [Cu4.232+Mg.sub.0.02 Al.sub.1.76 (OH).sub.12 ](CO.sub.3).sub.0.82 (SO.sub.4).sub.0.01 [Si(OH).sub.6 ].sub.0.05 â3H.sub.2 O. Unit-cell parameters of marioantofilliite are a=5.590(3), b=2.9358(11), c=7.675(3) Ã, β=100.958(17)°, and V=123.66(9) Ã.sup.3, with space group C2/m and Z=1/3. The crystal structure was refined to R.sub.1 =0.0372 for 181 unique reflections with F4Ï(F) and 23 refined parameters. It is topologically similar to that of other hydrotalcite-supergroup minerals and shows a distorted 001 brucite-like layer with Cu and Al statistically occupying an octahedrally coordinated M(1) site. The interlayer hosts disordered CO.sub.3 and H.sub.2 O groups. Marioantofilliite formed through the oxidative dissolution of primary Cu ores by mine drainage aqueous solutions and neutralization by gangue carbonates. Its name honours Mario Antofilli (1920-1983) for his contributions to the knowledge of the mineralogy of Liguria.

The coupling behaviour of H.sup.+ and trace elements in rutile has been studied using in situ polarised Fourier transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. H.sub.2 O contents in rutile can be precisely and accurately quantified from polarised FTIR measurements on single grains in situ. The benefits of this novel approach compared to traditional quantification methods are the preservation of textural context and heterogeneities of water in rutile. Rutile from six different geological environments shows H.sub.2 O contents varying between â¼ 50-2200 µg g.sup.-1, with large intra-grain variabilities for vein-related samples with H.sub.2 O contents between â¼ 500 and â¼ 2200 µg g.sup.-1 . From FTIR peak deconvolutions, six distinct OH absorption bands have been identified at â¼ 3280, â¼ 3295, â¼ 3324, â¼ 3345, â¼ 3370, and â¼ 3390 cm.sup.-1 that can be related to coupled substitutions with Ti.sup.3+, Fe.sup.3+, Al.sup.3+, Mg.sup.2+, Fe.sup.2+, and Cr.sup.2+, respectively. Rutile from eclogite samples displays the dominant exchange reactions of Ti.sup.4+ â Ti.sup.3+, Fe.sup.3+ + H.sup.+, whereas rutile in a whiteschist shows mainly Ti.sup.4+ â Al.sup.3+ + H.sup.+ . Trace-element-dependent H.sup.+ contents combined with LA-ICP-MS trace-element data reveal the significant importance of H.sup.+ for charge balance and trace-element coupling with trivalent cations. Trivalent cations are the most abundant impurities in rutile, and there is not enough H.sup.+ and pentavalent cations like Nb and Ta for a complete charge balance, indicating that additionally oxygen vacancies are needed for charge balancing trivalent cations. Valance states of multivalent trace elements can be inferred from deconvoluted FTIR spectra. Titanium occurs at 0.03 0/00-7.6 0/00 as Ti.sup.3+, Fe, and Cr are preferentially incorporated as Fe.sup.3+ and Cr.sup.3+ over Fe.sup.2+ and Cr.sup.2+, and V most likely occurs as V.sup.4+ . This opens the possibility of H.sup.+ in rutile as a potential indicator of oxygen fugacity of metamorphic and subduction-zone fluids, with the ratio between Ti.sup.3+ - and Fe.sup.3+ -related H.sup.+ contents being most promising.

The new mineral species freitalite, C.sub.14 H.sub.10, corresponding to the aromatic hydrocarbon anthracene, has been discovered on the mine dump of the Königin Carola shaft (also named Paul Berndt Mine), Freital, near Dresden, Saxony, Germany. The mineral forms thin blades or flakes of irregular shape up to a few millimetres in size and shows an intense violet or whitish-violet to white colour. Freitalite is a product of pyrolysis of coal at low oxygen fugacity and was formed by sublimation from a gas phase. The mineral is associated with sulfur and hoelite. Elemental analysis gave (in wt. %, average of three analyses) C 94.07, H 5.571 and total 99.641. The empirical formula is C.sub.14.00 H.sub.9.88 (calculated for C = 14). The identity with anthracene was confirmed by infrared and Raman spectroscopy, high-performance liquid chromatography, gas chromatography with mass spectrometry, .sup.1 H and .sup.13 C NMR spectrometry, and X-ray powder diffraction. Freitalite is monoclinic, P2.sub.1 /a, with lattice parameters a=8.5572(9), b=6.0220(5), c=11.173(1) Ã, β=124.174(1).sup.\" and V=476.34(3) Ã.sup.3 refined from powder data. The calculated density of 1.242 g cm.sup.-3 (for Z=2) is very close to the measured density of 1.240 g cm.sup.-3 . Freitalite was accepted as a new mineral by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2019-116).

Fluor-rewitzerite, [(H.sub.2 O)K]Mn.sub.2 (Al.sub.2 Ti)(PO.sub.4).sub.4 (OF)(H.sub.2 O).sub.10 â4H.sub.2 O, is a new monoclinic member of the paulkerrite group, from the Hagendorf-Süd pegmatite, Oberpfalz (Upper Palatinate in English), Bavaria, Germany. It occurs on the walls of vugs in corroded zwieselite, in association with Zn- and Al-bearing earlshannonite, fluorapatite, jahnsite-(CaMnMn) and Al-rich strunzite. Fluor-rewitzerite forms clusters of colourless stubby prisms up to 0.1 mm long that are flattened on 010; elongated along [100]; and show the forms 100, 010, 001, 111 and 111-. Twinning occurs by 2-fold rotation about c. The measured density is 2.42(2) g cm.sup.-3 . Optically, fluor-rewitzerite crystals are biaxial (+), with α = 1.569(3), β = 1.582(3), γ = 1.602(3) (white light) and 2V(meas) = 78(1)°. The empirical formula from electron microprobe analyses and structure refinement is .sup.A1 [(H.sub.2 O).sub.0.85 K.sub.0.15 ].sub.Σ1.00 .sup.A2 (K.sub.1.00) .sup.M1 (Mn.sup.2+ .sub.1.50 Mg.sub.0.09 Fe.sup.2+ .sub.0.41).sub.Σ2.00 .sup.M2+M3 (Al.sub.1.70 Ti.sup.4+ .sub.0.89 Fe.sup.3+ .sub.0.42).sub.Σ3.01 (PO.sub.4).sub.3.99 .sup.X (O.sub.1.09 F.sub.0.92).sub.Σ2.01 (H.sub.2 O).sub.10 â4.12H.sub.2 O. Fluor-rewitzerite has monoclinic symmetry with space group P2.sub.1 /c and unit-cell parameters a = 10.407(1) Ã, b = 20.514(2) Ã, c = 12.193(1) Ã, β = 90.49(2)°, V = 2603.0(4) Ã.sup.3 and Z = 4. The crystal structure was refined using synchrotron single-crystal data to R.sub.obs =0.058 for 6186 reflections with I3Ï(I). Fluor-rewitzerite is the fluoride analogue of rewitzerite, with F dominant over OH at the X sites of the general formula A1A2M1.sub.2 M2.sub.2 M3(PO.sub.4).sub.4 X.sub.2 (H.sub.2 O).sub.10 â4H.sub.2 O.

The new mineral zvÄstovite-(Fe), ideally Ag.sub.6 (Ag.sub.4 Fe.sub.2 )As.sub.4 S.sub.13, has been found in the small abandoned Ulatayskoe Ag-Cu-Co occurrence, Ovyurskiy District, Tuva Republic, eastern Siberia, Russia. It occurs as anhedral grains, up to 1 x 0.4 mm in size but usually much smaller, closely intergrown with native silver, in Mg-bearing siderite-quartz gangue. Other associated minerals include acanthite, cobaltite, As-rich members of the tetrahedrite group (kenoargentotennantite-(Fe), tennantite-(Zn), zvÄstovite-(Zn)), gersdorffite, jalpaite, krutovite, löllingite, pearceite, safflorite, skutterudite, Br-bearing chlorargyrite, malachite, and muscovite. ZvÄstovite-(Fe) is iron black and opaque and has a black streak and metallic lustre. It is brittle and has a conchoidal fracture. No cleavage or parting is observed. The Vickers micro-indentation hardness (Vickers hardness number, VHN; 25 g load) is 169 kg mm.sup.-2 (range of 149-187 kg mm.sup.-2, n=4), corresponding to a Mohs hardness of 3-3.5. The calculated density is 4.979 g cm.sup.-3 . In reflected light, zvÄstovite-(Fe) is light grey with a greenish tint and isotropic. Internal reflections are ubiquitous and deep red in colour. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are (R, %): 32.5 (470 nm), 31.1 (546 nm), 30.1 (589 nm), and 28.8 (650 nm). The chemical composition (wt %, electron microprobe data, mean of eight spot analyses) is as follows: Cu 1.81, Ag 56.02, Fe 4.60, Zn 0.01, As 13.85, Sb 2.63, S 21.50, total 100.42. The empirical formula, calculated on the basis of 16 atoms per formula unit, is Ag.sub.9.93 Cu.sub.0.54 Fe.sub.1.58 As.sub.3.54 Sb.sub.0.41 S.sub.12.83 . ZvÄstovite-(Fe) is cubic and has a space group of I4-3m, with a=10.8601(3), V=1280.86(11) Ã.sup.3, and Z=2. The strongest lines of the X-ray powder diffraction pattern (d, Ã (I, %) hkl) are 7.68 (11) 110, 3.136 (100) 222, 2.717 (12) 400, 1.984 (8) 521, 1.921 (23) 440, and 1.638 (11) 622. The crystal structure of zvÄstovite-(Fe) was refined to R.sub.1 =0.0551 for 400 unique reflections with F.sub.o >4Ï (F.sub.o). The possible ordering of the split M(2) sites is discussed. The new mineral is the Fe isotype of zvÄstovite-(Zn). Both these minerals form the zvÄstovite series within the tetrahedrite group.