Mendigite,Mn2Mn2MnCa(Si3O9)2, a new mineral species of the bustamite group from the Eifel volcanic region,Germany

A new mineral, mendigite (IMA no. 2014-007), isostructural with bustamite, has been found in the In den Dellen pumice quarry near Mendig, Laacher Lake area, Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. Associated minerals are sanidine, nosean, rhodonite, tephroite, magnetite, and a pyrochlore-group mineral. Mendigite occurs as clusters of long-prismatic crystals (up to 0.1 × 0.2 × 2.5 mm in size) in cavities within sanidinite. The color is dark brown with a brown streak. Perfect cleavage is parallel to (001). D _calc = 3.56 g/cm³. The IR spectrum shows the absence of H₂O and OH groups. Mendigite is biaxial (–), α = 1.722 (calc), β = 1.782(5), γ = 1.796(5), 2V _meas = 50(10)°. The chemical composition (electron microprobe, mean of 4 point analyses, the Mn²⁺/Mn³⁺ ratio determined from structural data and charge-balance constraints) is as follows (wt %): 0.36 MgO, 10.78 CaO, 37.47 MnO, 2.91 Mn₂O₃, 4.42 Fe₂O₃, 1.08 Al₂O₃, 43.80 SiO₂, total 100.82. The empirical formula is Mn_2.00(Mn_1.33Ca_0.67) (Mn_0.50 ²⁺ Mn_0.28 ³⁺ Fe_0.15 ³⁺ Mg_0.07)(Ca_0.80 (Mn_0.20 ²⁺)(Si_5.57 Fe_0.27 ³⁺ Al_0.16O₁₈). The idealized formula is Mn₂Mn₂MnCa(Si₃O₉)₂. The crystal structure has been refined for a single crystal. Mendigite is triclinic, space group \(P\bar 1\); the unit-cell parameters are a = 7.0993(4), b = 7.6370(5), c = 7.7037(4) Å, α = 79.58(1)°, β = 62.62(1)°, γ = 76.47(1)°; V = 359.29(4) ų, Z = 1. The strongest reflections on the X-ray powder diffraction pattern [d, Å (I, %) (hkl)] are: 3.72 (32) (020), 3.40 (20) (002, 021), 3.199 (25) (012), 3.000 (26), (\(01\bar 2\), \(1\bar 20\)), 2.885 (100) (221, \(2\bar 11\), \(1\bar 21\)), 2.691 (21) (222, \(2\bar 10\)), 2.397 (21) (\(02\bar 2\), \(21\bar 1\), 203, 031), 1.774 (37) (412, \(3\bar 21\)). The type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4420/1.     

Tinnunculite,C<Subscript>5</Subscript>H<Subscript>4</Subscript>N<Subscript>4</Subscript>O<Subscript>3</Subscript> · 2H<Subscript>2</Subscript>O: Occurrences on the Kola Peninsula and Redefinition and Validation as a Mineral Species

Based on a study of samples found in the Khibiny (Mt. Rasvumchorr: the holotype) and Lovozero (Mts Alluaiv and Vavnbed) alkaline complexes on the Kola Peninsula, Russia, tinnunculite was approved by the IMA Commission on New Minerals, Nomenclature, and Classification as a valid mineral species (IMA no. 2015-02la) and, taking into account a revisory examination of the original material from burnt dumps of coal mines in the southern Urals, it was redefined as crystalline uric acid dihydrate (UAD), C₅H₄N₄O₃ · 2H₂O. Tinnunculite is poultry manure mineralized in biogeochemical systems, which could be defined as “guano microdeposits.” The mineral occurs as prismatic or tabular crystals up to 0.01 × 0.1 × 0.2 mm in size and clusters of them, as well as crystalline or microglobular crusts. Tinnunculite is transparent or translucent, colorless, white, yellowish, reddish or pale lilac. Crystals show vitreous luster. The mineral is soft and brittle, with a distinct (010) cleavage. D_calc = 1.68 g/cm³ (holotype). Tinnunculite is optically biaxial (–), α = 1.503(3), β = 1.712(3), γ = 1.74(1), 2V_obs = 40(10)°. The IR spectrum is given. The chemical composition of the holotype sample (electron microprobe data, content of H is calculated by UAD stoichiometry) is as follows, wt %: 37.5 О, 28.4 С, 27.0 N, 3.8 H_calc, total 96.7. The empirical formula calculated on the basis of (C + N+ O) = 14 apfu is: C_4.99H₈N_4.07O_4.94. Tinnunculite is monoclinic, space group (by analogy with synthetic UAD) P2₁/c. The unit cell parameters of the holotype sample (single crystal XRD data) are a = 7.37(4), b = 6.326(16), c = 17.59(4) Å, β = 90(1)°, V = 820(5) ų, Z = 4. The strongest reflections in the XRD pattern (d, Å–I[hkl]) are 8.82–84[002], 5.97–15[011], 5.63–24[102?, 102], 4.22–22[112], 3.24–27[114?,114], 3.18–100[210], 3.12–44[211?, 211], 2.576–14[024].     

Lahnsteinite, Zn4(SO4)(OH)6 · 3H2O, a new mineral from the Friedrichssegen Mine, Germany

A new mineral, lahnsteinite, has been found in the dump of the Friedrichssegen Mine, Bad Ems district, Rhineland-Palatinate (Rheinland-Pfalz), Germany. Lahnsteinite, occurring as colorless tabular crystals in the cavities of goethite, is associated with pyromorphite, hydrozincite, quartz, and native copper. The Mohs’ hardness is 1.5; the cleavage is perfect parallel to (001). D _calc = 2.995 g/cm³, D _meas = 2.98(2) g/cm³. The IR spectrum is given. The new mineral is optically biaxial, negative, α = 1.568(2), β = 1.612(2), γ = 1.613(2), 2V _meas = 18(3)°, 2V _calc = 17°. The chemical composition (wt %, electron microprobe data; H₂O was determined by gas chromatography of ignition products) is as follows: 3.87 FeO, 1.68 CuO, 57.85 ZnO, 15.83 SO₃, 22.3 H₂O, total is 101.53. The empirical formula is (Zn_3.3Fe_0.27Cu_0.11)_Σ3.91(S_0.98O₄)(OH)₅ · 3H_2.10O. The crystal structure has been studied on a single crystal. Lahnsteinite is triclinic, space group P1, a = 8.3125(6), b = 14.545(1), c = 18.504(2) Å, α = 89.71(1), β = 90.05(1), γ = 90.13(1)°, V = 2237.2(3) ų, Z = 8. The strong reflections in the X-ray powder diffraction pattern [d, Å (I, %)] are: 9.30 (100), 4.175 (18), 3.476 (19), 3.290 (19), 2.723 (57), 2.624 (36), 2.503 (35), 1.574 (23). The mineral has been named after its type locality near the town of Lahnstein. The type specimen of lahnsteinite is deposited in the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, registration number 4252/1.     

Zinc-rich and copper-bearing amphiboles from sulfide-free ore occurrences of the Pelagonian Massif,Republic of North Macedonia

Mineralogy and Petrology - This paper describes specific features of isomorphism of unusual amphiboles containing up to 23&nbsp;wt% ZnO and up to 1.3&nbsp;wt% CuO from sulfide-free...     

Perrierite-(La), (La,Ce,Ca)4(Fe2+,Mn)(Ti,Fe3+,Al)4(Si2O7)2O8, a new mineral species from the Eifel volcanic district, Germany

Non-metamict perrierite-(La) discovered in the Dellen pumice quarry, near Mendig, in the Eifel volcanic district, Rheinland-Pfalz, Germany has been approved as a new mineral species (IMA no. 2010-089). The mineral was found in the late assemblage of sanidine, phlogopite, pyrophanite, zirconolite, members of the jacobsite-magnetite series, fluorcalciopyrochlore, and zircon. Perrierite-(La) occurs as isolated prismatic crystals up to 0.5 × 1 mm in size within cavities in sanidinite. The new mineral is black with brown streak; it is brittle, with the Mohs hardness of 6 and distinct cleavage parallel to (001). The calculated density is 4.791 g/cm³. The IR spectrum does not contain absorption bands that correspond to H₂O and OH groups. Perrierite-(La) is biaxial (-), α = 1.94(1), β = 2.020(15), γ = 2.040(15), 2V _meas = 50(10)°, 2V _calc = 51°. The chemical composition (electron microprobe, average of seven point analyses, the Fe²⁺/Fe³⁺ ratio determined from the X-ray structural data, wt %) is as follows: 3.26 CaO, 22.92 La₂O₃, 19.64 Ce₂O₃, 0.83 Pr₂O₂, 2.09 Nd₂O₃, 0.25 MgO, 2.25 MnO, 3.16 FeO, 5.28 Fe₂O₃, 2.59 Al₂O₃, 16.13 TiO₂, 0.75 Nb₂O₅, and 20.06 SiO₂, total is 99.21. The empirical formula is (La_1.70Ce_1.45Nd_0.15Pr_0.06Ca_0.70)_Σ4.06(Fe _0.53 ²⁺ Mn_0.38Mg_0.08)_Σ0.99(Ti_2.44Fe _0.80 ³⁺ Al_0.62Nb_0.07)_Σ3.93Si_4.04O₂₂. The simplified formula is (La,Ce,Ca)₄(Fe²⁺,Mn)(Ti,Fe³⁺,Al)₄(Si₂O₇)₂O₈. The crystal structure was determined by a single crystal. Perrierite-(La) is monoclinic, space group P2₁/a, and the unit-cell dimensions are as follows: a =13.668(1), b = 5.6601(6), c = 11.743(1) Å, β = 113.64(1)°; V = 832.2(2) ų, Z = 2. The strong reflections in the X-ray powder diffraction pattern are [d, Å (I, %) (hkl)]: 5.19 (40) (110), 3.53 (40) ( $\overline 3 $ 11), 2.96 (100) ( $\overline 3 $ 13, 311), 2.80 (50) (020), 2.14 (50) ( $\overline 4 $ 22, $\overline 3 $ 15, 313), 1.947 (50) (024, 223), 1.657 (40) ( $\overline 4 $ 07, $\overline 4 $ 33, 331). The holotype specimen of perrierite-(La) is deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, with the registration number 4059/1.     

Osumilite-(Mg): Validation as a mineral species and new data

Osumilite-(Mg), the Mg-dominant analogue of osumilite, has been approved by the CNMNC IMA as a new mineral species. The holotype sample has been found at Bellerberg, Eifel volcanic area, Germany. Fluorophlogopite, sanidine, cordierite, mullite, sillimanite, topaz, pseudobrookite and hematite are associated minerals. Osumilite-(Mg) occurs as short prismatic or thick tabular hexagonal crystals reaching 0.5 × 1 mm in size in the cavities in basaltic volcanic glasses at their contact with thermally metamorphosed xenoliths of pelitic rocks. The mineral is brittle, with Mohs’ hardness 6.5. Cleavage was not observed. Color is blue to brown. D _meas = 2.59(1), D _calc = 2.595 g/cm³. No bands corresponding to H₂O and OH-groups are in the IR spectrum. Osumilite-(Mg) is uniaxial (+), ω = 1.539(2), ? = 1.547(2). The chemical composition (electron microprobe, average of 5 point analyses, wt %) is: 0.08 Na₂O, 3.41 K₂O, 0.04 CaO, 7.98 MgO, 0.28 MnO, 21.57 Al₂O₃, 3.59 Fe₂O₃, 62.33 SiO₂, total 99.28. The empirical formula is: (K_0.72Na_0.03Ca_0.01)(Mg_1.97Mn_0.04)[Al_4.21Fe _0.45 ³⁺ Si_10.32]O₃₀. The simplified formula is: KMg₂Al₃(Al₂Si₁₀)O₁₀. The crystal structure was refined on a single crystal, R = 0.0294. Osumilite-(Mg) is hexagonal, space group P6/mcc; a = 10.0959(1), c = 14.3282(2)Å, V = 1264.79(6) ų, Z = 2. The strongest reflections in the X-ray powder diffraction pattern [d, Å I %) (hkl)] are: 7.21 (37) (002), 5.064 (85) (110), 4.137 (45) (112), 3.736 (43) (202), 3.234 (100) (211), 2.932 (42) (114), 2.767 (51) (204). A type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.     

Hillesheimite, (K,Ca,□)2(Mg,Fe,Ca,□)2[(Si,Al)13O23(OH)6](OH) · 8H2O, a new phyllosilicate mineral of the Günterblassite group

A new mineral, hillesheimite, has been found in the Graulai basaltic quarry, near the town of Hillesheim, the Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. It occurs in the late assemblage comprising nepheline, augite, fluorapatite, magnetite, perovskite, priderite, götzenite, lamprophyllite-group minerals, and åkermanite. Colorless flattened crystals of hillesheimite reaching 0.2 × 1 × 1.5 mm in size and aggregates of the crystals occur in miarolitic cavities in alkali basalt. The mineral is brittle, with Mohs’ hard-ness 4. Cleavage is perfect parallel to (010) and distinct on (100) and (001). D _calc = 2.174 g/cm³, D _meas = 2.16(1) g/cm³. IR spectrum is given. Hillesheimite is biaxial (?), α = 1.496(2), β = 1.498(2), γ = 1.499(2), 2V _meas = 80°. The chemical composition (electron microprobe, mean of 4 point analyses, H₂O determined from structural data, wt %) is as follows: 0.24 Na₂O, 4.15 K₂O, 2.14 MgO, 2.90 CaO, 2.20 BaO, 2.41 FeO, 15.54 Al₂O₃, 52.94 SiO₂, 19.14 H₂O, total is 101.65. The empirical formula is: K_0.96Na_0.08Ba_0.16Ca_0.56Mg_0.58Fe _0.37 ²⁺ [Si_9.62Al_3.32O₂₃(OH)₆][(OH)_0.82(H₂O)_0.18] · 8H₂O. The crystal structure has been determined from X-ray single-crystal diffraction data, R = 0.1735. Hillesheimite is orthorhombic, space group Pmmn, the unit-cell dimensions are: a = 6.979(11), b = 37.1815(18), c = 6.5296(15) Å; V=1694(3) ų, Z = 2. The crystal structure is based on the block [(Si,Al)₁₃O₂₅(OH)₄] consisting of three single tetrahedral layers linked via common vertices and is topologically identical to the triple layers in günterblassite and umbrianite. The strong reflections [d Å (I %)] in the X-ray powder diffraction pattern are: 6.857(58), 6.545(100), 6.284(53), 4.787(96), 4.499(59), 3.065(86), 2.958(62), 2.767(62). The mineral was named after its type locality. Type specimens are deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.