ALBERT

Description: 〈div data-abstract-type="normal"〉〈p〉Pampaloite, AuSbTe, is a new mineral discovered in the Pampalo gold mine, 65 km east of Joensuu, Finland. It forms anhedral grains (up to ~20 μm) intergrown with gold, frohbergite and altaite. Pampaloite is brittle and has a metallic lustre. Values of VHN〈span〉25〈/span〉 lie between 245 and 295 kg/mm〈span〉2〈/span〉, with a mean value of 276 kg/mm〈span〉2〈/span〉, corresponding to a Mohs hardness of ~4–5 (measured on synthetic material). In plane-polarised light, pampaloite is white with medium to strong bireflectance, weak reflectance pleochroism from slightly pinkish brown to slightly bluish white (only visible in grains of synthetic material containing multiple orientations), and strong anisotropy, with blue to light brown rotation tints; it exhibits no internal reflections. Reflectance values of pampaloite in air (〈span〉R〈/span〉〈span〉1,〈/span〉〈span〉R〈/span〉〈span〉2〈/span〉 in %) are: 60.0, 62.5 at 470 nm, 62.5, 64.8 at 546 nm, 63.2, 65.6 at 589 nm and 63.7, 66.0 at 650 nm. Ten electron-microprobe analyses of natural pampaloite give an average composition: Au 44.13, Sb 27.44 and Te 28.74, total 100.31 wt.%, corresponding to the empirical formula Au〈span〉1.00〈/span〉Sb〈span〉1.00〈/span〉Te〈span〉1.00〈/span〉 based on 3 atoms; the average of eleven analyses on synthetic pampaloite is: Au 44.03, Sb 27.26, and Te 29.08, total 100.38 wt.%, corresponding to Au〈span〉0.99〈/span〉Sb〈span〉1.00〈/span〉Te〈span〉1.01〈/span〉. The density, calculated on the basis of the empirical formula, is 9.33 g/cm〈span〉3〈/span〉.The mineral is monoclinic, space group 〈span〉C〈/span〉2/〈span〉c〈/span〉, with 〈span〉a〈/span〉 = 11.947(3), 〈span〉b〈/span〉 = 4.481(1) Å, 〈span〉c〈/span〉 = 12.335(3) Å, β = 105.83(2)°, 〈span〉V〈/span〉 = 635.3(3) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 8. The crystal structure was solved and refined from the single-crystal X-ray-diffraction data of synthetic AuSbTe. The pampaloite crystal structure can be considered as a monoclinic derivative of the CdI〈span〉2〈/span〉 structure composed of [AuTe〈span〉3〈/span〉Sb〈span〉3〈/span〉] octahedra. The strongest lines in the powder X-ray diffraction pattern of synthetic pampaloite [〈span〉d〈/span〉 in Å (〈span〉I〈/span〉) (〈span〉hkl〈/span〉)] are: 4.846(24)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉02), 3.825(18)(111), 2.978(100)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline2.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉11), 2.968(50)(004), 2.242(25)(020), 2.144(55)(313), 2.063(33)(〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20190709073523038-0660:S0026461X18001299:S0026461X18001299_inline3.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉15) and 1.789(18)(024).〈/p〉〈/div〉

Description: 〈div data-abstract-type="normal"〉 〈p〉This study presents a complete characterization of kenoplumbomicrolite, (Pb,□)〈span〉2〈/span〉Ta〈span〉2〈/span〉O〈span〉6〈/span〉[□,(OH),O], occurring in an amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.〈/p〉 〈p〉Kenoplumbomicrolite occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm, has a white streak, a greasy lustre and is translucent. The Mohs hardness is ~6. Attempts to measure density (7.310–7.832 g/cm〈span〉3〈/span〉) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and immersed in oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb〈span〉1.30〈/span〉□〈span〉0.30〈/span〉Ca〈span〉0.29〈/span〉Na〈span〉0.08〈/span〉U〈span〉0.03〈/span〉)〈span〉Σ2.00〈/span〉(Ta〈span〉0.82〈/span〉Nb〈span〉0.62〈/span〉Si〈span〉0.23〈/span〉Sn〈span〉4+〈/span〉〈span〉0.15〈/span〉Ti〈span〉0.07〈/span〉Fe〈span〉3+〈/span〉〈span〉0.10〈/span〉Al〈span〉0.01〈/span〉)〈span〉Σ2.00〈/span〉O〈span〉6〈/span〉[□〈span〉0.52〈/span〉(OH)〈span〉0.25〈/span〉O〈span〉0.23〈/span〉]〈span〉Σ1.00〈/span〉 (from the crystal used for the structural study) and (Pb〈span〉1.33〈/span〉□〈span〉0.66〈/span〉Mn〈span〉0.01〈/span〉)〈span〉Σ2.00〈/span〉(Ta〈span〉0.87〈/span〉Nb〈span〉0.72〈/span〉Sn〈span〉4+〈/span〉〈span〉0.18〈/span〉Fe〈span〉3+〈/span〉〈span〉0.11〈/span〉W〈span〉0.08〈/span〉Ti〈span〉0.04〈/span〉)〈span〉Σ2.00〈/span〉O〈span〉6〈/span〉[□〈span〉0.80〈/span〉(OH)〈span〉0.10〈/span〉O〈span〉0.10〈/span〉]〈span〉Σ1.00〈/span〉 (average including additional fragments). The mineral is cubic, space group 〈span〉Fd〈/span〉〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/resource/id/urn:cambridge.org:id:binary:20181109112359083-0385:S0026461X18000075:S0026461X18000075_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉〈span〉m〈/span〉. The unit-cell parameters refined from powder X-ray diffraction data are 〈span〉a〈/span〉 = 10.575(2) Å and 〈span〉V〈/span〉 = 1182.6(8) Å〈span〉3〈/span〉, which are in accord with those obtained previously from a single crystal of 〈span〉a〈/span〉 = 10.571(1) Å, 〈span〉V〈/span〉 = 1181.3(2) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 8. The mineral description and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-007a).〈/p〉 〈/div〉

Description: 〈div data-abstract-type="normal"〉〈p〉Mitrofanovite, Pt〈span〉3〈/span〉Te〈span〉4〈/span〉, is a new telluride discovered in low-sulfide disseminated ore in the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia. It forms anhedral grains (up to ~20 μm × 50 μm) commonly in intergrowths with moncheite in aggregates with lukkulaisvaaraite, kotulskite, vysotskite, braggite, keithconnite, rustenburgite and Pt–Fe alloys hosted by a chalcopyrite–pentlandite–pyrrhotite matrix. Associated silicates are: orthopyroxene, augite, olivine, amphiboles and plagioclase. Mitrofanovite is brittle; it has a metallic lustre and a grey streak. Mitrofanovite has a good cleavage, along {001}. In plane-polarised light, mitrofanovite is bright white with medium to strong bireflectance, slight pleochroism, and strong anisotropy on non-basal sections with greyish brown rotation tints; it exhibits no internal reflections. Reflectance values for the synthetic analogue of mitrofanovite in air (〈span〉R〈/span〉〈span〉o〈/span〉, 〈span〉R〈/span〉〈span〉e’〈/span〉 in %) are: 58.4, 54.6 at 470 nm; 62.7, 58.0 at 546 nm; 63.4, 59.1 at 589 nm; and 63.6, 59.5 at 650 nm. Fifteen electron-microprobe analyses of mitrofanovite gave an average composition: Pt 52.08, Pd 0.19, Te 47.08 and Bi 0.91, total 100.27 wt.%, corresponding to the formula (Pt〈span〉2.91〈/span〉Pd〈span〉0.02〈/span〉)〈span〉Σ2.93〈/span〉(Te〈span〉4.02〈/span〉Bi〈span〉0.05〈/span〉)〈span〉Σ4.07〈/span〉 based on 7 atoms; the average of eleven analyses on synthetic analogue is: Pt 52.57 and Te 47.45, total 100.02 wt.%, corresponding to Pt〈span〉2.94〈/span〉Te〈span〉4.06〈/span〉. The density, calculated on the basis of the formula, is 11.18 g/cm〈span〉3〈/span〉. The mineral is trigonal, space group 〈span〉R〈/span〉〈span〉〈span〉〈img data-mimesubtype="gif" data-type="simple" src="http://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20190902090145754-0317:S0026461X18001500:S0026461X18001500_inline1.gif"〉 〈span data-mathjax-type="texmath"〉 〈/span〉 〈/span〉〈/span〉〈span〉m〈/span〉, with 〈span〉a〈/span〉 = 3.9874(1), 〈span〉c〈/span〉 = 35.361(1) Å, 〈span〉V〈/span〉 = 486.91(2) Å〈span〉3〈/span〉 and 〈span〉Z〈/span〉 = 3. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Pt〈span〉3〈/span〉Te〈span〉4〈/span〉. Mitrofanovite is structurally and chemically related to moncheite (PtTe〈span〉2〈/span〉). The strongest lines in the powder X-ray diffraction pattern of synthetic mitrofanovite [〈span〉d〈/span〉 in Å (〈span〉I〈/span〉) (〈span〉hkl〈/span〉)] are: 11.790(23)(003), 5.891(100)(006), 2.851(26)(107), 2.137(16)(10〈span〉13〈/span〉), 2.039(18)(01〈span〉14〈/span〉), 1.574(24)(01〈span〉20〈/span〉), 1.3098(21)(00〈span〉27〈/span〉). The structural identity of natural mitrofanovite with synthetic Pt〈span〉3〈/span〉Te〈span〉4〈/span〉 was confirmed by electron backscatter diffraction measurements on the natural sample. The mineral name is chosen to honour Felix P. Mitrofanov, a Russian geologist who was among the first to discover platinum-group element mineralisation in the Fedorova–Pana complex.〈/p〉〈/div〉

Description: Mitrofanovite, Pt3Te4, is a new telluride discovered in low-sulfide disseminated ore in the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia. It forms anhedral grains (up to ~20 μm × 50 μm) commonly in intergrowths with moncheite in aggregates with lukkulaisvaaraite, kotulskite, vysotskite, braggite, keithconnite, rustenburgite and Pt–Fe alloys hosted by a chalcopyrite–pentlandite–pyrrhotite matrix. Associated silicates are: orthopyroxene, augite, olivine, amphiboles and plagioclase. Mitrofanovite is brittle; it has a metallic lustre and a grey streak. Mitrofanovite has a good cleavage, along {001}. In plane-polarised light, mitrofanovite is bright white with medium to strong bireflectance, slight pleochroism, and strong anisotropy on non-basal sections with greyish brown rotation tints; it exhibits no internal reflections. Reflectance values for the synthetic analogue of mitrofanovite in air (Ro, Re’ in %) are: 58.4, 54.6 at 470 nm; 62.7, 58.0 at 546 nm; 63.4, 59.1 at 589 nm; and 63.6, 59.5 at 650 nm. Fifteen electron-microprobe analyses of mitrofanovite gave an average composition: Pt 52.08, Pd 0.19, Te 47.08 and Bi 0.91, total 100.27 wt.%, corresponding to the formula (Pt2.91Pd0.02)Σ2.93(Te4.02Bi0.05)Σ4.07 based on 7 atoms; the average of eleven analyses on synthetic analogue is: Pt 52.57 and Te 47.45, total 100.02 wt.%, corresponding to Pt2.94Te4.06. The density, calculated on the basis of the formula, is 11.18 g/cm3. The mineral is trigonal, space group R$overline 3 $m, with a = 3.9874(1), c = 35.361(1) Å, V = 486.91(2) Å3 and Z = 3. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Pt3Te4. Mitrofanovite is structurally and chemically related to moncheite (PtTe2). The strongest lines in the powder X-ray diffraction pattern of synthetic mitrofanovite [d in Å (I) (hkl)] are: 11.790(23)(003), 5.891(100)(006), 2.851(26)(107), 2.137(16)(1013), 2.039(18)(0114), 1.574(24)(0120), 1.3098(21)(0027). The structural identity of natural mitrofanovite with synthetic Pt3Te4 was confirmed by electron backscatter diffraction measurements on the natural sample. The mineral name is chosen to honour Felix P. Mitrofanov, a Russian geologist who was among the first to discover platinum-group element mineralisation in the Fedorova–Pana complex.

Description: Pampaloite, AuSbTe, is a new mineral discovered in the Pampalo gold mine, 65 km east of Joensuu, Finland. It forms anhedral grains (up to ~20 μm) intergrown with gold, frohbergite and altaite. Pampaloite is brittle and has a metallic lustre. Values of VHN 25 lie between 245 and 295 kg/mm 2 , with a mean value of 276 kg/mm 2 , corresponding to a Mohs hardness of ~4–5 (measured on synthetic material). In plane-polarised light, pampaloite is white with medium to strong bireflectance, weak reflectance pleochroism from slightly pinkish brown to slightly bluish white (only visible in grains of synthetic material containing multiple orientations), and strong anisotropy, with blue to light brown rotation tints; it exhibits no internal reflections. Reflectance values of pampaloite in air ( R 1, R 2 in %) are: 60.0, 62.5 at 470 nm, 62.5, 64.8 at 546 nm, 63.2, 65.6 at 589 nm and 63.7, 66.0 at 650 nm. Ten electron-microprobe analyses of natural pampaloite give an average composition: Au 44.13, Sb 27.44 and Te 28.74, total 100.31 wt.%, corresponding to the empirical formula Au 1.00 Sb 1.00 Te 1.00 based on 3 atoms; the average of eleven analyses on synthetic pampaloite is: Au 44.03, Sb 27.26, and Te 29.08, total 100.38 wt.%, corresponding to Au 0.99 Sb 1.00 Te 1.01 . The density, calculated on the basis of the empirical formula, is 9.33 g/cm 3 .The mineral is monoclinic, space group C 2/ c , with a = 11.947(3), b = 4.481(1) Å, c = 12.335(3) Å, β = 105.83(2)°, V = 635.3(3) Å 3 and Z = 8. The crystal structure was solved and refined from the single-crystal X-ray-diffraction data of synthetic AuSbTe. The pampaloite crystal structure can be considered as a monoclinic derivative of the CdI 2 structure composed of [AuTe 3 Sb 3 ] octahedra. The strongest lines in the powder X-ray diffraction pattern of synthetic pampaloite [ d in Å ( I ) ( hkl )] are: 4.846(24)( 2¯ 02), 3.825(18)(111), 2.978(100)( 3¯ 11), 2.968(50)(004), 2.242(25)(020), 2.144(55)(313), 2.063(33)( 3¯ 15) and 1.789(18)(024).

Description: Oscarkempffite, ideally Ag10Pb4(Sb17Bi9)∑=26S48, is a new mineral species found in old material (1929–30) from the Colorada vein, Animas mine, Chocaya Province, Department of Potosi, Bolivia. It is associated with aramayoite, stannite, miargyrite, pyrargyrite and tetrahedrite. Oscarkempffite forms anhedral grains and grain aggregates up to 10 mm across. The mineral is opaque, greyish black with a metallic lustre; it is brittle without any discernible cleavage. In reflected light oscarkempffite is greyish white, pleochroism is distinct, white to dark grey. Internal reflections are absent. In crossed polars, anisotropism is distinct with rotation tints in shades of grey. The reflectance data (%, air) are: 39.9, 42.6 at 470 nm, 38.6, 41.7 at 546 nm, 38.1, 41.2 at 589 nm and 37.3, 40.6 at 650 nm. Mohs hardness is 3–3½, microhardness VHN50 exhibits a range 189–208, with a mean value 200 kg mm–2. The average results of four electron-microprobe analyses in a grain are: Cu 0.24(7), Ag 14.50(8), Pb 11.16(14), Sb 28.72(16), Bi 24.56(17), S 20.87(5), total 100.05(6) wt.%, corresponding to Cu0.24Ag9.92Pb4.00Sb17.36Bi8.64S47.84 (on the basis of Me + S = 88 apfu). The simplified formula, Ag10Pb4Sb17Bi9S48, is in accordance with the results of a crystal-structure determination. The density, 5.8 g cm–3, was calculated using the ideal formula. Oscarkempffite has an orthorhombic cell with a = 13.199(2), b = 19.332(3), c = 8.249(1) Å, V = 2116.3(5) Å3, space group Pnca and Z = 1. The strongest eight lines in the (calculated) powder-diffraction pattern are [d in Å(I)hkl]: 3.66(35)(122), 3.37(70)(132), 3.34(100)(250), 2.982(55)(312), 2.881(86)(322), 2.733(29)(332), 2.073(27)(004) and 2.062(31)(182). Comparison with gustavite, andorite and roshchinite confirms its independence as a mineral species.