First occurrence of Mn-dominant cordierite-group mineral: electron microprobe and laser ablation ICPMS study

2019 ◽  
Vol 57 (5) ◽  
pp. 807-810
Author(s):  
Adam Szuszkiewicz ◽  
Adam Pieczka ◽  
Petr Gadas ◽  
Michaela Vašinová-Galiová ◽  
Eligiusz Szełęg ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Electron Microprobe ◽  
Group Mineral ◽  
First Occurrence

Kummerite, Mn2+Fe3+Al(PO4)2(OH)2·8H2O, a new laueite-group mineral from the Hagendorf Süd pegmatite, Bavaria, with ordering of Al and Fe3+

2016 ◽  
Vol 80 (7) ◽  
pp. 1243-1254 ◽  
Author(s):  
I. E. Grey ◽  
E. Keck ◽  
W. G. Mumme ◽  
A. Pring ◽  
C. M. Macrae ◽  
...  
Keyword(s):  
Electron Microprobe ◽  
Empirical Formula ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Group Mineral ◽  
X Ray ◽  
Cell Parameters ◽  
Octahedral Sites ◽  
Phosphate Mineral

AbstractKummerite, ideally Mn2+Fe3+A1(PO4)2(OH)2.8H2O, is a new secondary phosphate mineral belonging to the laueite group, from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Kummerite occurs as sprays or rounded aggregates of very thin, typically deformed, amber yellow laths. Cleavage is good parallel to ﹛010﹜. The mineral is associated closely with green Zn- and Al-bearing beraunite needles. Other associated minerals are jahnsite-(CaMnMn) and Al-bearing frondelite. The calculated density of kummerite is 2.34 g cm 3. It is optically biaxial (-), α= 1.565(5), β = 1.600(5) and y = 1.630(5), with weak dispersion. Pleochroism is weak, with amber yellow tones. Electron microprobe analyses (average of 13 grains) with H2O and FeO/Fe2O3 calculated on structural grounds and normalized to 100%, gave Fe2O3 17.2, FeO 4.8, MnO 5.4, MgO 2.2, ZnO 0.5, Al2O3 9.8, P2O5 27.6, H2O 32.5, total 100 wt.%. The empirical formula, based on 3 metal apfu is (Mn2+0.37Mg0.27Zn0.03Fe2+0.33)Σ1.00(Fe3+1.06Al0. 94)Σ2.00PO4)1.91(OH)2.27(H2O)7.73. Kummerite is triclinic, P1̄, with the unit-cell parameters of a = 5.316(1) Å, b =10.620(3) Å , c = 7.118(1) Å, α = 107.33(3)°, β= 111.22(3)°, γ = 72.22(2)° and V= 348.4(2) Å3. The strongest lines in the powder X-ray diffraction pattern are [dobs in Å(I) (hkl)] 9.885 (100) (010); 6.476 (20) (001); 4.942 (30) (020); 3.988 (9) (̄110); 3.116 (18) (1̄20); 2.873 (11) (1̄21). Kummerite is isostructural with laueite, but differs in having Al and Fe3+ ordered into alternate octahedral sites in the 7.1 Å trans-connected octahedral chains.

Awaruite, iridian awaruite, and a new Ru-Os-Ir-Ni-Fe alloy from the Sakhakot-Qila complex, Malakand Agency, Pakistan

1981 ◽  
Vol 44 (334) ◽  
pp. 225-230 ◽  
Author(s):  
Zulfiqar Ahmed ◽  
J. C. Bevan
Keyword(s):  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Atomic Percent ◽  
First Occurrence ◽  
First Time ◽  
Different Parts

AbstractThe authors report the first occurrence of awaruite in Pakistan, in the Sakhakot-Qila ultramafites. Electron-microprobe analysis reveals a considerable variation in the compositions of awaruites from different parts of the complex. The presence of copper in awaruite, in amounts up to 5 atomic percent, is also reported for the first time. In one chromitite body, an iridian awaruite with up to 27 wt% of iridium occurs in association with ‘normal’ awaruite and a new Ru-Os-Ir-Ni-Fe alloy. The awaruites are discussed in relation to those from other localities.

Arsenopyrite and As-bearing pyrite from the Roudný deposit, Bohemian Massif

2004 ◽  
Vol 68 (1) ◽  
pp. 31-46 ◽  
Author(s):  
J. Zachariáš ◽  
J. Frýda ◽  
B. Paterová ◽  
M. Mihaljevič
Keyword(s):  
Laser Ablation ◽  
Fluid Inclusion ◽  
Electron Microprobe ◽  
Gold Deposits ◽  
Fluid Inclusion Data ◽  
The Core ◽  
Trace Element Chemistry ◽  
Mineral Phases ◽  
Icp Ms ◽  
Substitution Mechanism

AbstractThe major- and trace-element chemistry of pyrite and arsenopyrite from the mesothermal Roudný gold deposits was studied by electron microprobe and laser ablation ICP-MS techniques. In total, four generations of pyrite and two of arsenopyrite were distinguished. The pyrite is enriched in As through an Fe (AsxS1–x)2 substitution mechanism. The As-rich zones of pyrite-2 (up to 4.5 wt.% As) are also enriched in gold (up to 20 ppm), lead (commonly up to 220 ppm, exceptionally up to 1500 ppm) and antimony (commonly <600 ppm, rarely up to 1350 ppm). Positive correlation of As and Au in the studied pyrites is not coupled with an Fe deficiency, in contrast to Au-rich As-bearing pyrites in Carlintype gold deposits. The As-rich pyrite-2 coprecipitated with the Sb-rich (1 –4.2 wt.%) and Au-rich (40 –150 ppm) arsenopyrite-1. The younger arsenopyrite-2 is significantly less enriched in these elements (0 –70 ppm of Au).The chemical zonality of pyrites in the Roudný gold deposits reflects the chemical evolution of orebearing fluids that are not observed in any other mineral phases. The data available suggest relatively high activity of sulphur and low activities of arsenic and gold during crystallization of the older pyrite generation (pyrite-1). Later, after particular dissolution of pyrite-1, Au-rich As-bearing pyrite-2 and arsenopyrite precipitated. These facts suggest a marked increase in the arsenic and gold activities in ore-bearing fluids. The As-content of pyrite-2 decreases in an oscillatory manner from the core to the rim, reflecting changes in the As activity or/and in the P-T conditions. The As-bearing pyrites were formed at temperatures of at least 320–330°C, based on arsenopyrite thermometers and fluid inclusion data.

Canutite, NaMn3[AsO4][AsO3(OH)]2, a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile

2014 ◽  
Vol 78 (4) ◽  
pp. 787-795 ◽  
Author(s):  
A. R. Kampf ◽  
S. J. Mills ◽  
F. Hatert ◽  
B. P. Nash ◽  
M. Dini ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
White Light ◽  
Electron Microprobe ◽  
New Mineral ◽  
Optical Orientation ◽  
Calculated Density ◽  
Secondary Alteration ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness

AbstractThe new mineral canutite (IMA2013-070), NaMn3[AsO4][AsO3(OH)]2, was found at two different locations at the Torrecillas mine, Salar Grande, Iquique Province, Chile, where it occurs as a secondary alteration phase in association with anhydrite, halite, lavendulan, magnesiokoritnigite, pyrite, quartz and scorodite. Canutite is reddish brown in colour. It forms as prisms elongated on [20] and exhibiting the forms {010}, {100}, {10}, {201} and {102}, or as tablets flattened on {102} and exhibiting the forms {102} and {110}. Crystals are transparent with a vitreous lustre. The mineral has a pale tan streak, Mohs hardness of 2½, brittle tenacity, splintery fracture and two perfect cleavages, on {010} and {101}. The calculated density is 4.112 g cm−3. Optically, canutite is biaxial (+) with α = 1.712(3), β = 1.725(3) and γ = 1.756(3) (measured in white light). The measured 2V is 65.6(4)°, the dispersion is r < v (slight), the optical orientation is Z = b; X ^ a = 18° in obtuse β and pleochroism is imperceptible. The mineral is slowly soluble in cold, dilute HCl. The empirical formula (for tabular crystals from near the mineshaft), determined from electron - microprobe analyses, is (Na1.05Mn2.64Mg0.34Cu0.14Co0.03)∑4.20As3O12H1.62. Canutite is monoclinic, C2/c, a = 12.3282(4), b = 12.6039(5), c = 6.8814(5) Å, β = 113.480(8)°, V = 980.72(10) Å3 and Z = 4. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 6.33(34)(020), 4.12(26)(21), 3.608(29)(310,31), 3.296(57)(12), 3.150(28)(002,131), 2.819(42)(400,041,330), 2.740(100)(240,02,112) and 1.5364(31)(multiple). The structure, refined to R1 = 2.33% for 1089 Fo > 4σF reflections, shows canutite to be isostructural with protonated members of the alluaudite group.

Comparison of accuracy, precision, and sensitivity in elemental assays of fish otoliths using the electron microprobe, proton-induced X-ray emission, and laser ablation inductively coupled plasma mass spectrometry

1997 ◽  
Vol 54 (9) ◽  
pp. 2068-2079 ◽  
Author(s):  
S E Campana ◽  
S R Thorrold ◽  
C M Jones ◽  
D Günther ◽  
M Tubrett ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Elemental Composition ◽  
Electron Microprobe ◽  
Inductively Coupled Plasma ◽  
X Ray ◽  
Inductively Coupled ◽  
Accuracy And Precision ◽  
Plasma Mass Spectrometry ◽  
Fish Otoliths

The elemental composition of fish otoliths is of considerable interest to those who wish to reconstruct temperature, migration, or environmental histories of individual fish based on assays of the otolith growth sequence. However, reported differences in otolith elemental composition among studies may be due in part to performance differences among four of the most popular instruments for targeted elemental analysis: wavelength-dispersive electron microprobe (WD-EM), energy-dispersive electron microprobe (ED-EM), proton-induced X-ray emission (PIXE), and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). To rigorously compare the sensitivity, accuracy, and precision of these four analytical tools, the International Otolith Composition Experiment distributed blind-labelled real and artificial otoliths of known but varied elemental composition to eight laboratories for assay of 10 selected elements. No one instrument type was sensitive to each element, nor was any one instrument preferred for use in all assays. In general however, abundant elements such as Na and K could only be measured accurately with an electron microprobe, while the trace elements required PIXE or LA-ICPMS. Strontium could be measured with considerable accuracy and precision by WD-EM, PIXE, and LA-ICPMS. The presence of significant, and occasionally large, differences among laboratories suggests that comparisons among published studies should be made cautiously and only after appropriate calibration.

Crystal chemistry of zinc incorporation in strunzite-group minerals containing zeolitic water

2017 ◽  
Vol 81 (5) ◽  
pp. 1051-1062 ◽  
Author(s):  
I. E. Grey ◽  
E. Keck ◽  
C. M. MacRae ◽  
A. M. Glenn ◽  
A. R. Kampf ◽  
...  
Keyword(s):  
Water Molecule ◽  
Comparative Study ◽  
Electron Microprobe ◽  
Interlayer Water ◽  
Compositional Zoning ◽  
Group Mineral ◽  
Zeolitic Water ◽  
Interlayer Region ◽  
Cation Substitutions ◽  
Interlayer Water Molecule

AbstractA comparative study is presented of the chemistry and crystallography of zinc-bearing strunzites from Hagendorf Süd, Bavaria, Germany and the Sitio do Castelo mine, Folgosinho, Portugal. Electron microprobe analyses of samples from the two localities show quite different cation substitutions. The Hagendorf Süd mineral is a Zn-bearing ferristrunzite, with compositional zoning due to Zn2+ replacing predominantly Fe3+ as well as minor Mn2+, whereas the Portugese mineral is a Zn-bearing strunzite, in which Zn2+ replaces Mn2+, with minor replacement of Fe3+ by Mn3+. Zincostrunzite, with dominant Zn in the interlayer octahedrally coordinated site, is a new strunzite-group mineral that has been characterized at both locations. Analysis of single-crystal synchrotron data for zinc-bearing ferristrunzite and zincostrunzite crystals from Hagendorf Süd show that the structures of both minerals contain zeolitic water in the interlayer region. The formula for strunzite-group minerals containing the zeolitic water is MFe23+(PO4)2(OH)2·6.5H2O, M=Fe, Mn, Zn. This formulation agrees with that found for zincostrunzite from the Sitio do Castelo mine, but differs from that reported previously for strunzite, MFe2+(PO4)2(OH)2·6H2O, which has no interlayer water. Interestingly, the zincostrunzites from the two localities differ in the location of the interlayer water molecule, with a corresponding difference in the H bonding.

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