Krasnoshteinite, Al8[B2O4(OH)2](OH)16Cl4⋅7H2O, a New Microporous Mineral with a Novel Type of Borate Polyanion

A new mineral, krasnoshteinite (Al8[B2O4(OH)2](OH)16Cl4⋅7H2O), was found in the Verkhnekamskoe potassium salt deposit, Perm Krai, Western Urals, Russia. It occurs as transparent colourless tabular to lamellar crystals embedded up to 0.06 x 0.25 x 0.3 mm in halite-carnallite rock and is associated with dritsite, dolomite, magnesite, quartz, baryte, kaolinite, potassic feldspar, congolite, members of the goyazite–woodhouseite series, fluorite, hematite, and anatase. Dmeas = 2.11 (1) and Dcalc = 2.115 g/cm3. Krasnoshteinite is optically biaxial (+), α = 1.563 (2), β = 1.565 (2), γ = 1.574 (2), and 2Vmeas = 50 (10)°. The chemical composition (wt.%; by combination of electron microprobe and ICP-MS; H2O calculated from structure data) is: B2O3 8.15, Al2O3 46.27, SiO2 0.06, Cl 15.48, H2Ocalc. 33.74, –O=Cl –3.50, totalling 100.20. The empirical formula calculated based on O + Cl = 33 apfu is (Al7.87Si0.01)Σ7.88[B2.03O4(OH)2][(OH)15.74(H2O)0.26]Σ16[(Cl3.79(OH)0.21]Σ4⋅7H2O. The mineral is monoclinic, P21, a = 8.73980 (19), b = 14.4129 (3), c = 11.3060 (3) Å, β = 106.665 (2)°, V = 1364.35 (5) Å3, and Z = 2. The crystal structure of krasnoshteinite (solved using single-crystal data, R1 = 0.0557) is unique. It is based upon corrugated layers of Al-centered octahedra connected via common vertices. BO3 triangles and BO2(OH)2 tetrahedra share a common vertex, forming insular [B2O4(OH)2]4− groups (this is a novel borate polyanion) which are connected with Al-centered octahedra via common vertices to form the aluminoborate pseudo-framework. The structure is microporous, zeolite-like, with a three-dimensional system of wide channels containing Cl- anions and weakly bonded H2O molecules. The mineral is named in honour of the Russian mining engineer and scientist Arkadiy Evgenievich Krasnoshtein (1937–2009). The differences in crystal chemistry and properties between high-temperature and low-temperature natural Al borates are discussed

Dritsite, Li2Al4(OH)12Cl2·3H2O, a New Gibbsite-Based Hydrotalcite Supergroup Mineral

Dritsite, ideally Li2Al4(OH)12Cl2·3H2O, is a new hydrotalcite supergroup mineral formed as a result of diagenesis in the halite−carnallite rock of the Verkhnekamskoe salt deposit, Perm Krai, Russia. Dritsite forms single lamellar or tabular hexagonal crystals up to 0.25 mm across. The mineral is transparent and colourless, with perfect cleavage on {001}. The chemical composition of dritsite (wt. %; by combination of electron microprobe and ICP−MS; H2O calculated by structure refinement) is: Li2O 6.6, Al2O3 45.42, SiO2 0.11, Cl 14.33, SO3 0.21, H2Ocalc. 34.86, O = Cl − 3.24, total 98.29. The empirical formula based on Li + Al + Si = 6 apfu (atom per formula unit) is Li1.99Al4.00Si0.01[(OH)12.19Cl1.82(SO4)0.01]Σ14.02·2.60(H2O). The Raman spectroscopic data indicate the presence of O–H bonding in the mineral, whereas CO32– groups are absent. The crystal structure has been refined in the space group P63/mcm, a = 5.0960(3), c = 15.3578(13) Å, and V = 345.4(5) Å3, to R1 = 0.088 using single-crystal data. The strongest lines of the powder X-ray diffraction pattern (d, Å (I, %) (hkl)) are: 7.68 (100) (002), 4.422 (61) (010), 3.832 (99) (004, 012), 2.561 (30) (006), 2.283 (25) (113), and 1.445 (26) (032). Dritsite was found as 2H polytype, which is isotypic with synthetic material and shows strong similarity to chlormagalumite-2H. The mineral is named in honour of the Russian crystallographer and mineralogist Prof. Victor Anatol`evich Drits

Unique PGE–Cu–Ni Noril’sk Deposits, Siberian Trap Province: Magmatic and Tectonic Factors in Their Origin

The unique and very large PGE⁻Cu⁻Ni Noril’sk deposits are located within the Siberian trap province, posing a number of questions about the relationship between the ore-forming process and the magmatism that produced the traps. A successful answer to these questions could greatly increase the possibility of discovering new deposits in flood basalt provinces elsewhere. In this contribution, we present new data on volcanic stratigraphy and geochemistry of the magmatic rocks in the key regions of the Siberian trap province (Noril’sk, Taimyr, Maymecha-Kotuy, Kulyumber, Lower Tunguska and Angara) and analyze the structure of the north part of the province. The magmatic rocks of the Arctic zone are characterized by variable MgO (3.6⁻37.2 wt %) and TiO2 (0.8⁻3.9 wt %) contents, Gd/Yb (1.4⁻6.3) and La/Sm (2.0⁻10.4) ratios, and a large range of isotopic compositions. The intrusions in the center of the Tunguska syneclise and Angara syncline have much less variable compositions and correspond to a “typical trap„ with MgO of 5.6⁻7.2 wt %, TiO2 of 1.0⁻1.6 wt %, Gd/Yb ratio of 1.4⁻1.6 and La/Sm ratio of 2.0⁻3.5. This compositional diversity of magmas in the Arctic zone is consistent with their emplacement within the paleo-rift zones. Ore-bearing intrusions (the Noril’sk 1, Talnakh, Kharaelakh) are deep-situated in the Igarka-Noril’sk rift zone, which has three branches, namely the Bolsheavamsky, Dyupkunsky, and Lower Tunguska, that are prospected for discovering new deposits. One possible explanation for the specific position of the PGE⁻Cu⁻Ni deposits is accumulation of sulfides in these long-lived zones from the Neoproterozoic to the Mesozoic era during magmatic and metamorphic processes. Thus, trap magmatism, itself, does not produce large deposits, but mobilizes earlier formed sulfide segregations in addition carrying metals in the original magmas. These deposits are the results of several successive magmatic events, in which emplacement of the traps was the final event

Ferro-pedrizite, NaAl2(Fe2+2Al2Li)Si8O22(OH)2,a new amphibole-supergroup mineral from the Sutlug pegmatite, Tyva Republic, Russia

Ferro-pedrizite, a new amphibole-supergroup mineral was discovered in the Sutlug pegmatite occurrence situated in the Targi River Basin, Tyva Republic, Eastern Sibera, Russia. The associated minerals are quartz, albite, microcline, spodumene, cassiterite, beryl, columbite-(Mn), fergusonite-b-(Y), fluorapatite, schorl, trilithionite and fluorite. Ferro-pedrizite forms dark grey-blue to violet-blue acicular and long prismatic crystals up to 2 5 50 mm and their aggregates. Dmeas ¼ 3.16(1) g/cm3 (by hydrostatic weighing), 3.13(1) g/cm3 (by flotation in heavy liquids); Dcalc ¼ 3.135 g/cm3. Ferro-pedrizite is optically biaxial (–), a ¼ 1.614(3), b ¼ 1.638(3), g ¼ 1.653(3), 2Vmeas ¼ 75(5), 2Vcalc ¼ 76. The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, the ratio Fe2þ:Fe3þ by Mo¨ssbauer data, Li by ICP-MS, H2O by gas chromatography of ignition products, F bywet analysis,wt. %): Li2O4.67,Na2O2.54,K2O 0.13, MgO 4.48, CaO 0.29, MnO 0.59, FeO 9.06, Al2O3 13.13, Fe2O3 4.60, SiO2 57.59, F 1.15, H2O 1.50, -O ¼ F –0.48, total 99.25. The empirical formula based on 24 anions is: Na0.60K0.02)P0.62(Li1.89Na0.07Ca0.04)P2.00(Fe2þ1.03Mg0.90Mn2þ0.07Al1.88Fe3þ0.47Li0.65)P5.00 [(Si7.79Al0.21)P8.00O22][(OH)1.36F0.49O0.15)]. The simplified formula is NaLi2(Fe2þ2Al2Li)Si8O22(OH)2. Ferro-pedrizite is monoclinic, C2/m, a ¼ 9.3716(4), b ¼ 17.649(1), c ¼ 5.2800(6) A ° , b ¼ 102.22(1), V ¼ 853.5(1) A ° 3, Z ¼ 2. The structure has been refined to Robs ¼ 3.9 % (4843 I . 2sI). A twinning model was introduced into the refinement through the matrix [–1 0 0/0–1 0/–0.7516 0 1] with the ratio of two twin components of 0.681(3)/0.319(3). The strongest lines of the powder X-ray diffraction pattern [d, A° (I, %) (hkl)] are: 8.147 (52) (110), 4.420 (22), (040), 3.009 (100) (310), 2.7102 (28) (330), 2.6865 (29) (151), 2.6236 (21) (461). Type material is deposited in the Mineralogical Museum of the Tomsk State University, Tomsk, Russia

Ferro-pedrizite, NaAl2(Fe2+2Al2Li)Si8O22(OH)2,a new amphibole-supergroup mineral from the Sutlug pegmatite, Tyva Republic, Russia

Ferro-pedrizite, a new amphibole-supergroup mineral was discovered in the Sutlug pegmatite occurrence situated in the Targi River Basin, Tyva Republic, Eastern Sibera, Russia. The associated minerals are quartz, albite, microcline, spodumene, cassiterite, beryl, columbite-(Mn), fergusonite-b-(Y), fluorapatite, schorl, trilithionite and fluorite. Ferro-pedrizite forms dark grey-blue to violet-blue acicular and long prismatic crystals up to 2 5 50 mm and their aggregates. Dmeas ¼ 3.16(1) g/cm3 (by hydrostatic weighing), 3.13(1) g/cm3 (by flotation in heavy liquids); Dcalc ¼ 3.135 g/cm3. Ferro-pedrizite is optically biaxial (–), a ¼ 1.614(3), b ¼ 1.638(3), g ¼ 1.653(3), 2Vmeas ¼ 75(5), 2Vcalc ¼ 76. The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, the ratio Fe2þ:Fe3þ by Mo¨ssbauer data, Li by ICP-MS, H2O by gas chromatography of ignition products, F bywet analysis,wt. %): Li2O4.67,Na2O2.54,K2O 0.13, MgO 4.48, CaO 0.29, MnO 0.59, FeO 9.06, Al2O3 13.13, Fe2O3 4.60, SiO2 57.59, F 1.15, H2O 1.50, -O ¼ F –0.48, total 99.25. The empirical formula based on 24 anions is: Na0.60K0.02)P0.62(Li1.89Na0.07Ca0.04)P2.00(Fe2þ1.03Mg0.90Mn2þ0.07Al1.88Fe3þ0.47Li0.65)P5.00 [(Si7.79Al0.21)P8.00O22][(OH)1.36F0.49O0.15)]. The simplified formula is NaLi2(Fe2þ2Al2Li)Si8O22(OH)2. Ferro-pedrizite is monoclinic, C2/m, a ¼ 9.3716(4), b ¼ 17.649(1), c ¼ 5.2800(6) A ° , b ¼ 102.22(1), V ¼ 853.5(1) A ° 3, Z ¼ 2. The structure has been refined to Robs ¼ 3.9 % (4843 I . 2sI). A twinning model was introduced into the refinement through the matrix [–1 0 0/0–1 0/–0.7516 0 1] with the ratio of two twin components of 0.681(3)/0.319(3). The strongest lines of the powder X-ray diffraction pattern [d, A° (I, %) (hkl)] are: 8.147 (52) (110), 4.420 (22), (040), 3.009 (100) (310), 2.7102 (28) (330), 2.6865 (29) (151), 2.6236 (21) (461). Type material is deposited in the Mineralogical Museum of the Tomsk State University, Tomsk, Russia