An unusual titanium-rich oxide mineral from Oslo, Norway

European Journal of Mineralogy, 2010

Heftetjernite, ideally ScTaO 4 , is a new scandium mineral from the Heftetjern pegmatite, Tørdal, Telemark, Norway. In the type specimen, it occurs as minute, elongate tabular, very dark brown crystals in a single small void in albite. Other associated minerals are fluorite, muscovite, altered milarite, a metamict, dark greyish brown mineral of the pyrochlore-microlite group, and an unidentified, orange-brown, tabular, nearly X-ray amorphous Ti-Y-Ta-Nb-mineral. Electron-microprobe analysis yielded the empirical formula (Sc 0.64 Sn 0.13 Mn 0.12 Fe 0.08 Ti 0.06 ) AE1.03 (Ta 0.69 Nb 0.30 ) AE0.99 O 4 which clearly demonstrates the charge-balanced substitution scheme 2Sc 3þ ¼ (Sn,Ti) 4þ þ (Mn,Fe) 2þ . The mineral crystallises in the wolframite structure type, with space group P2/c and a ¼ 4.784

2018

Introduction The mineralogy of the amazonite pegmatite at Tennvatn was briefly described by Ellingsen et al. (1995, 2000). One of the unidentified phases, designated UK-2 (Ellingsen et al. 2000), is a metamict mineral occurring as well-formed crystals (Fig. 1). It has an unusual chemical composition. The purpose of the present publication is to present and discuss the electron-microprobe analytical data of the mineral.

Mineralogical Magazine

The crystal structure of kyzylkumite, ideally Ti2V3+O5(OH), from the Sludyanka complex in South Baikal, Russia was solved and refined (including the hydrogen atom position) to an agreement index, R1, of 2.34% using X-ray diffraction data collected on a twinned crystal. Kyzylkumite crystallizes in space group P21/c, with a = 8.4787(1), b = 4.5624(1), c = 10.0330(1) A˚ , b = 93.174(1)º, V = 387.51(1) A ˚ 3 and Z = 4. Tivanite, TiV3+O3OH, and kyzylkumite have modular structures based on hexagonal close packing of oxygen, which are made up of rutile [TiO2] and montroseite [V3+O(OH)] slices. In tivanite the rutile:montroseite ratio is 1:1, in kyzylkumite the ratio is 2:1. The montroseite module may be replaced by the isotypic paramontroseite V4+O2 module, which produces a phase with the formula Ti2V4+O6. In the metamorphic rocks of the Sludyanka complex, vanadium can be present as V4+ and V3+ within the same mineral (e.g. in batisivite, schreyerite and berdesinskiite). Kyzylkumite has a ...

Canadian Mineralogist, 2004

Tarkianite, a new mineral species of ideal composition (Cu,Fe)(Re,Mo) 4 S 8 , was recently discovered in sulfide concentrate from the Hitura Ni-Cu-PGE mine, Nivala, western central Finland. It is associated with pyrrhotite, pentlandite, valleriite, chalcopyrite, cubanite, mackinawite, chromite, and the PGE minerals sperrylite, michenerite, irarsite, froodite and hollingworthite. It is black, opaque with a metallic luster, a black streak, and is brittle with an irregular fracture. VHN 15 is in the range 537-584, which corresponds to a Mohs hardness of 5½ to 6. Under reflected plane-polarized light, the mineral is light brown-gray and isotropic. The CIE color values (illuminant C) are: x 0.314 (air), 0.315 (oil); y 0.321 (air), 0.323 (oil) Y: 38.9 (air), 21.7 (oil); d: 575 (air), 573 (oil); P e %: 2.1 (air), 3.2 (oil). The measured values of reflectance in air and oil for a single grain, respectively, are 38.02, 20.91 (470 nm), 37.87, 21.76 (546 nm), 39.18, 21.84 (589 nm), 39.30, 22.12 (650 nm) and values for 400-700 nm are tabulated. Tarkianite is cubic, F43m (by analogy with the synthetic equivalent), with unit-cell parameter refined from powder data: a 9.563(1) Å, V 874.5(1) Å 3 , Z = 4. The strongest eight lines of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 5.and 1.246(50)(731). D (calc.) is 7.30 g/cm 3 (for the empirical formula and unit-cell parameter). Averaged electron-microprobe data yielded Re 53.61, Mo 12.32, Cu 5.48, Os 0.84, Fe 0.59, Ni 0.09, Co 0.08, S 26.77, total 99.78 wt.%, corresponding to SOMMAIRE Nous décrivons la tarkianite, nouvelle espèce minérale de composition idéale (Cu,Fe)(Re,Mo) 4 S 8 , découverte récemment dans un concentré de sulfures provenant de la mine à Ni-Cu-EGP de Hitura, près de Nivala, dans le centre-ouest de la Finlande. Lui sont associés pyrrhotite, pentlandite, vallériite, chalcopyrite, cubanite, mackinawite, chromite, et les minéraux des éléments du groupe du platine (EGP) sperrylite, michenerite, irarsite, froodite et hollingworthite. Il s'agit d'un minéral noir, opaque avec un éclat métallique, et une rayure noire. Elle est cassante avec une fracture irrégulière. La dureté mesurée (VHN 15 ) est dans l'intervalle 537-584, ce qui correspond à 5½ ou 6 sur l'échelle de Mohs. En lumière réfléchie polarisée en plan, la tarkianite est §

Mineralogical Magazine, 2012

Kazanskyite, Ba&TiNbNa 3 Ti(Si 2 O 7 ) 2 O 2 (OH) 2 (H 2 O) 4 , is a Group-III TS-block mineral from the Kirovskii mine, Mount Kukisvumchorr, Khibiny alkaline massif, Kola Peninsula, Russia. The mineral occurs as flexible and commonly bent flakes 2À15 mm thick and up to 330 mm across. It is colourless to pale tan, with a white streak and a vitreous lustre. The mineral formed in a pegmatite as a result of hydrothermal activity. Associated minerals are natrolite, barytolamprophyllite, nechelyustovite, hydroxylapatite, belovite-(La), belovite-(Ce), gaidonnayite, nenadkevichite, epididymite, apophyllite-(KF) and sphalerite. Kazanskyite has perfect cleavage on {001}, splintery fracture and a Mohs hardness of 3. Its calculated density is 2.930 g cm À3 . Kazanskyite is biaxial positive with a 1.695, b 1.703, g 1.733 (l 590 nm), 2V meas = 64.8(7)º, 2V calc = 55.4º, with no discernible dispersion. It is not pleochroic. Kazanskyite is triclinic, space group P1 , a 5.4260 , b 7.135(1), c 25.514(4) Å , a 90.172(4), b 90.916(4), g 89.964(3)º, V 977.61(3) Å 3 . The strongest lines in the X-ray powderdiffraction pattern [d(Å )(I)(hkl)] are: 2.(OH) 2 (H 2 O) 4 . The Raman spectrum of the mineral contains the following bands: 3462 cm À1 (broad) and 3545 and 3628 cm À1 (sharp). The crystal structure was solved by direct methods and refined to an R 1 index of 8.09%. The crystal structure of kazanskyite is a combination of a TS (titanium silicate) block and an I (intermediate) block. The TS block consists of HOH sheets (H is heteropolyhedral and O is octahedral). The TS block exhibits linkage and stereochemistry typical for * Group-III (Ti = 3 a.p.f.u.) Ti-disilicate minerals. The TS block has two different H sheets where (Si 2 O 7 ) groups link to [5]-coordinated Ti and [6]-coordinated Nb polyhedra, respectively. There are two peripheral sites, A P (1,2), occupied mainly by Ba (less Sr and K) at 96% and 26%. There are two I blocks: the I 1 block is a layer of Ba atoms; the I 2 block consists of H 2 O groups and A P (2) atoms. The TS and I blocks are topologically identical to those in the nechelyustovite structure. The mineral is named in honour of Professor Vadim Ivanovich Kazansky (Вадим Иванович Казанский), a prominent Russian ore geologist and an expert in Precambrian metallogeny.

Mineralogical Magazine, 2007

Rinkite, ideally Na 2 Ca 4 REETi(Si 2 O 7 ) 2 OF 3 , is a common mineral in alkaline and peralkaline rocks. The crystal structures of five rinkite crystals from three alkaline massifs: Ilimaussaq, Greenland; Khibiny, Kola Peninsula, Russia and Mont Saint-Hilaire, Canada, have been refined as two components related by the TWIN matrix (À1 0 0, 0 À1 0, 1 0 1) (Mo-Ka radiation). The crystals, a = 7.4132À7.4414, b = 5.6595À5.6816, c = 18.8181À18.9431 Å , b = 101.353À101.424(2)º, V = 776.1À786.7 Å 3 , space group P2 1 /c, Z = 2, D calc = 3.376À3.502 g cm À3 , were analysed using an electron microprobe subsequent to collection of the X-ray intensity data. Transmission electron microscopy confirmed the presence of pseudomerohedral twinning in rinkite crystals. The crystal structure of rinkite is a framework of TS (titanium silicate) blocks. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). The TS block in rinkite exhibits linkage and stereochemistry typical for Group I (Ti = 1 a.p.f.u.) of Ti disilicate minerals: two H sheets connect to the O sheet such that two (Si 2 O 7 ) groups link to the trans edges of a Na polyhedron of the O sheet. The crystal chemistry of rinkite and nacareniobsite-(Ce) is discussed.

Mineralogy and Petrology, 2002

The Canadian Mineralogist, 2002

Gjerdingenite-Fe occurs as yellow prisms or laths up to 1 mm long in miarolitic cavities of a sodic granite ("ekerite") at Gjerdingselva, Lunner, Oppland, Oslo Region, Norway. The simplified formula is K 2 [(H 2 O) 2 (Fe,Mn)][(Nb,Ti) 4 (Si 4 O 12 ) 2 (OH,O) 4 ]•4H 2 O, i.e., the mineral is an analogue of those with root name kuzmenkoite, which have Ti > Nb. The mineral is monoclinic, C2/m, with a 14.529(2), b 13.943(2), c 7.837(2) Å, ␤ 117.61(1)°, V 1406.8(9) Å 3 , Z = 2. The crystal structure was refined to R = 0.054 on the basis of 1677 observed reflections; twinning on {001} simulates an orthorhombic F-centered lattice. The partitioning of cations and H 2 O molecules in the sites B, B', C (occupying channels of the zeolite-like structure) is discussed; for the refined crystal, the following crystal-chemical formula is established by comparison of chemical and structure-refinement data: {[K 1.20 Na 0.72 (H 2 O) 2.08 ] ⌺4 [K 2.08 (H 2 O) 1.92 ] ⌺4 }[(H 2 O) 3.40 K 0.56 Ca 0.04 ] ⌺4 (Fe 0.95 Mn 0.75 Ⅺ 0.30 ) ⌺2 (Nb 4.30 Ti 3.45 Fe 0.20 Zr 0.05 ) ⌺8 (Si 15.90 Al 0.10 ) ⌺16 O 48 [(OH) 4.16 O 3.84 ] ⌺8 •4H 2 O (Z = 1). The strongest six reflections of the powder pattern [d obs in Å(I)(hkl)] are: 6.92(80)(020,001), 6.42(50)(200,201), 4.94(70)(021), 3.225(100)(421,400,402), 3.114(80)(041,022), and 2.512(50)(441,401, 403). The mineral is optically biaxial (+) with ␣ 1.6676 , ␤ 1.7001(4), ␥ 1.794(1); 2V meas = 58.5(2.3)°, 2V calc = 63.71(1)°. The Mohs hardness is about 5; D meas = 2.82(2), D calc = 2.830 g/cm 3 . The pseudo-orthorhombic crystals are flattened on {001} and elongate along [010]. Five crystal forms were observed: {100}, {010} (subordinate), {001}, {201}, and {021}. SOMMAIRE La gjerdingenite-Fe se présente en prismes jaunes ou en lamelles atteignant 1 mm de long dans des cavités miarolitiques d'un granite sodique ("ékerite") à Gjerdingselva, Lunner, Oppland, dans la région d'Oslo, en Norvège. La formule simplifiée de cette nouvelle espèce serait: K 2 [(H 2 O) 2 (Fe,Mn)] [(Nb,Ti) 4 (Si 4 O 12 ) 2 (OH,O) 4 ]•4H 2 O, i.e., elle est un analogue des minéraux ayant la racine kuzmenkoïte dans leur nom, et donc Ti > Nb. La gjerdingenite-Fe est monoclinique, C2/m, a 14.529(2), b 13.943(2), c 7.837(2) Å, ␤ 117.61(1)°, V 1406.8(9) Å 3 , Z = 2. La structure cristalline en a été affinée jusqu'à un résidu R = 0.054 en utilisant 1677 réflexions observées; un maclage sur {001} simule une maille orthorhombique à faces centrées. Nous évaluons la répartition des cations et des molécules de H 2 O sur les sites B, B', C, qui occupent les canaux de cette structure, semblable à celle d'une zéolite; dans le cas du cristal qui a servi à l'affinement de la structure, voici la formule cristallochimique, établie en évaluant les données sur la composition et les résultats de l'affinement:{[K

Mineralogy and Petrology, 2002

Mineralogical Magazine, 2011

Rinkite, ideally Na 2 Ca 4 REETi(Si 2 O 7 ) 2 OF 3 , is a common mineral in alkaline and peralkaline rocks. The crystal structures of five rinkite crystals from three alkaline massifs: Ilimaussaq, Greenland; Khibiny, Kola Peninsula, Russia and Mont Saint-Hilaire, Canada, have been refined as two components related by the TWIN matrix (À1 0 0, 0 À1 0, 1 0 1) (Mo-Ka radiation). The crystals, a = 7.4132À7.4414, b = 5.6595À5.6816, c = 18.8181À18.9431 Å , b = 101.353À101.424(2)º, V = 776.1À786.7 Å 3 , space group P2 1 /c, Z = 2, D calc = 3.376À3.502 g cm À3 , were analysed using an electron microprobe subsequent to collection of the X-ray intensity data. Transmission electron microscopy confirmed the presence of pseudomerohedral twinning in rinkite crystals. The crystal structure of rinkite is a framework of TS (titanium silicate) blocks. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). The TS block in rinkite exhibits linkage and stereochemistry typical for Group I (Ti = 1 a.p.f.u.) of Ti disilicate minerals: two H sheets connect to the O sheet such that two (Si 2 O 7 ) groups link to the trans edges of a Na polyhedron of the O sheet. The crystal chemistry of rinkite and nacareniobsite-(Ce) is discussed.