Sweetite, a new mineral from Derbyshire

1984 ◽  
Vol 48 (347) ◽  
pp. 267-269 ◽  
Author(s):  
A. M. Clark ◽  
E. E. Fejer ◽  
A. G. Couper ◽  
G. C. Jones
Keyword(s):  
Chemical Analysis ◽  
Powder Pattern ◽  
Tetragonal Symmetry ◽  
New Mineral ◽  
X Ray ◽  
Naturally Occurring ◽  
Cell Dimensions

AbstractSweetite, naturally occurring Zn(OH)2 with tetragonal symmetry, has been found at Milltown, near Ashover, Derbyshire. It occurs as colourless or whitish bipyramids up to 1 mm in size scattered over the surface of colourless fluorite cubes. The cell dimensions are α 8,222 and c 14.34Å with Z = 20. The strongest lines of the X-ray powder pattern are (d, I, hkl): 4.53 37 (112); 3.572 60 (004,202,211); 2.922 100 (213,220); 2.708 18 (105,204); 2.257 17 (224,215,321); 1.840 11 (226,420,413); 1.764 24 (316). Sweetite is uniaxial negative, ω 1.635, ɛ 1.628. Dmeas is close to 3.33 and Dcalc 3.41. Chemical analysis gave 84.3% ZnO and 17.0% H2O, while theoretical figures for Zn(OH)2 are 81.9 and 18.1% respectively.

Ranunculite, AlH(UO2)(PO4)(OH)3 · 4H2O, a new mineral

1979 ◽  
Vol 43 (327) ◽  
pp. 321-323 ◽  
Author(s):  
Michel Dellens ◽  
Paul Piret
Keyword(s):  
Chemical Analysis ◽  
Electron Microprobe ◽  
Powder Pattern ◽  
New Mineral ◽  
Calculated Density ◽  
X Ray ◽  
Mean Diameter ◽  
Measured Density

SummaryRanunculite occurs as gold-yellow nodules. Mean diameter = 0.3 mm. Optically biaxial negative, 2V (calc.) = 56°. γ =1.670, β = 1.664, and α = 1.643. Monoclinic, pseudo-orthorhombic with a = 11.1 Å, b = 17.7 Å, c = 18.0 Å, and β ⋍ 90°. Z = 14. Measured density = 3.4 g/cm3. Calculated density = 3.39 g/cm3. The strongest lines of the X-ray powder pattern are (d, hkl, I): 9.00, 002–020 (100), 3.133, 330 (80), 470, 202–220 (50), 2.978, 006–060 (40), and 1.850, 600 (40). Chemical analysis by electron microprobe: Al2O3 9.9%, UO3 54.5%, P2O5 13.2%, H2O by thermogravimetry 20.3%. Formula: AlH(UO2)(PO4)(OH)3 · 4H2O. Ranunculite occurs at Kobokobo, Kivu, Zaïre, in pegmatitic rocks. The name after the colour (ranunculus = buttercup).

Kennedyite, a new mineral of the pseudobrookite series

1961 ◽  
Vol 32 (252) ◽  
pp. 676-682 ◽  
Author(s):  
O. von Knorring ◽  
K. G. Cox
Keyword(s):  
Chemical Analysis ◽  
Alkali Feldspar ◽  
New Mineral ◽  
X Ray ◽  
South Eastern ◽  
Approximate Composition ◽  
Southern Rhodesia ◽  
Hills Area

SummaryA new mineral with the approximate composition of Fe2MgTi3O10 and isostructural with pseudobrookite Fe4Ti2O10 has been observed in an olivine-augite-alkali-feldspar rock of the Karroo succession from the Mateke Hills area in south-eastern Southern Rhodesia. Chemical analysis and indexed X-ray powder data (α 9·77, b 9·95, c 3·73 Å.) of the mineral are given, and the name kennedyite is proposed. The name karrooite is proposed for the artificial product MgTi2O5.

Zeophyllite from Monte Somma, Vesuvius, Italy

1983 ◽  
Vol 47 (344) ◽  
pp. 397-400 ◽  
Author(s):  
Elio Passaglia ◽  
Cesare Porcelli
Keyword(s):  
Chemical Analysis ◽  
Calcium Silicate ◽  
Unit Cell ◽  
Powder Pattern ◽  
Chemical Formula ◽  
Anionic Sites ◽  
Welded Tuff ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Oxygen Atoms

AbstractZeophyllite, a rare calcium silicate, occurs at Monte Somma, Italy, as milky-white, slightly fibrous spherules associated with apophyllite on the surface of pumice in a welded tuff dated 472 AD. The chemical analysis and the indexed powder pattern, along with the chemical formula and unit cell dimensions calculated from these data, are given. The deficiency of Ca and Si cations and the abundance of (OH) and F anions in the chemical formula calculated on the basis of 38 anions (O + F) is interpreted as due to the presence of (O4H4) substituting for (SiO4) tetrahedra and of fluorine instead of oxygen atoms in two anionic sites.

The determination of composition and thermal history of plagioclase by the X-ray powder method

1955 ◽  
Vol 30 (229) ◽  
pp. 648-656 ◽  
Author(s):  
J. Goodyear ◽  
W. J. Duffin
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Similar Composition ◽  
X Ray ◽  
Naturally Occurring ◽  
Cell Dimensions ◽  
History Of ◽  
Unit Cell Dimensions ◽  
Ray Patterns

In a recent paper (hereafter referred to as GD) Goodyear and Dufiln (1954) described X-ray powder data for a number of synthetic and chemically analysed plagioclases of composition An0Abl00-Anl00Ab0. Important aspects of this work were a correlation of the X-ray patterns with chemical composition, and a distinction between the pattern of a naturally occurring material of low-temperature origin and that of a synthetic of similar composition. The investigation showed quite clearly that the unit-cell dimensions of a synthetic plagioelase depend but little on composition from An0Abl00 to An70Ab30, whilst they differ from those of the low-temperature modification greatly for albite, to a lessening degree as the composition approaches An70Ab30, and practically not at all in the range An70Ab30-Anl00Ab0.

scholarly journals On the Use of a Modified Radial Distribution Analysis for Indexing Powder Patterns

1962 ◽  
Vol 6 ◽  
pp. 18-24
Author(s):  
A. F. Berndt
Keyword(s):  
Radial Distribution ◽  
Unit Cell ◽  
Powder Pattern ◽  
Distribution Analysis ◽  
Trial And Error ◽  
Orthorhombic Unit Cell ◽  
X Ray ◽  
Tetragonal Unit Cell ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

AbstractA modification of the theory of X-ray radial distribution analysis is presented. This modification can serve as a guide to the values of the unit cell dimensions and may be useful in indexing powder patterns of unknown structures, although the use of trial and error methods is not eliminated. This technique is shown to give consistent results with known structures and is applied to the indexing of powder patterns of Pu3Ru and Pu5Ru3. The powder pattern of Pu3Ru can be indexed on the basis of an orthorhombic unit cell with a0 = 6.216 Å, b0 = 6.924 Å, and c0 = 8.093 Å, and Pu5Ru3 on the basis of a tetragonal unit cell with a0 = 8.092 Å and c0 - 10.023 Å.

Holtite: a new mineral allied to dumortierite

1971 ◽  
Vol 38 (293) ◽  
pp. 21-25 ◽  
Author(s):  
M. W. Pryce
Keyword(s):  
Optical Properties ◽  
Chemical Analysis ◽  
Western Australia ◽  
Prime Minister ◽  
Unit Cell ◽  
New Mineral ◽  
Space Group ◽  
Free Basis ◽  
X Ray ◽  
The Government

SummaryHoltite, a new mineral allied to dumortierite, occurred as pebbles with stibiotantalite and tantalite on an alluvial tin lease near Greenbushes, Western Australia, and is named after the late H. E. Holt, Prime Minister of Australia.The mineral is orthorhombic with a 11·905 Å, b 20·355 Å, c 4·690 Å, space group Pmcn, weak supercell 2a, 2b, c developed. Crystals are elongated along c, D 3·90 ± 0·02, hardness 8½, fluorescent. Optical properties α 1·743−1·746, mainly yellow, ‖ [001], β 1·756−1·759, colourless, γ 1·758−1·761, colourless, 2Vα 49−55°, r < v. X-ray powder data are given.Chemical analysis gave SiO2 20·30, Sb2O5 4·61, Al2O3 46·43, Ta2O5 11·24, Nb2O5 0·76, Fe2O3 0·27, MnO 0·05, TiO2 0·09, BeO 0·05, B2O3 1·82, Sb2O3 13·89, H2O+ 0·38, H2O− 0·08, sum 99·97%. On a water-free basis the unit cell contains Al24·5Sb2·56‴Ta1·36Sb0·76vNb0·16Fe0·10‴Be0·05Ti0·03Mn0·02B1·40‴Si9·09O66·85. Compared with dumortierite, 4[(A1,Fe)7BSi3O18] or 4 (X11O18), the holtite unit cell contains approximately 4(X10O17).Type material is preserved at the Government Chemical Laboratories, Perth, Western Australia.

An X-ray study of manganese minerals

1959 ◽  
Vol 32 (247) ◽  
pp. 332-339 ◽  
Author(s):  
Bibhuti Mukherjee
Keyword(s):  
Cell Size ◽  
Diffraction Method ◽  
Powder Pattern ◽  
Space Group ◽  
X Ray ◽  
Manganese Ores ◽  
Cell Dimensions ◽  
A Cell ◽  
New Space ◽  
Manganese Minerals

SummaryRhodonite, rhodochrosite, spandite, psilomelane, beldongrite, braunite, sitaparite, and vredenburgite from a collection hy Fermor have been studied by the X-ray powder diffraction method. The cell dimensions of all forms of eryptomelane—massive, horny, botryoidal, reniform, mamillated, and stalactitic—are a = 9.82 Å., c= 2.86 Å.. whereas the cell dimensions of shiny pitch-like beldongrite are a= 9.82 Å., c= 2·87 Å. The amorphous admixture associated with cryptomelane is revealed by a broad halo, 4·60 Å. to 3·90 Å., in the powder pattern. Aminoff's crystal data for braunite are discussed with a different orientation, and a new space group, I 4/mmm, is assigned after indexing the powder pattern. Fermor' sitaparite (bixbyite) is assigned a new space group Im3 , different from that proposed by Pauling et al., on the basis of a fresh indexing of the powder pattern. Manganese-garnet from the gondite series has a cell-size of the order of spessartine, whereas the cell-size of manganese-garnet from the kodurite series varies from 11·72 to 11·95 Å. Fermor's spandite from the kodurite series is a mixture of spessartine, grossular, and andradite garnet-molecules with almandine and pyrope as minor components. Ramsdellite and γ-MnO2 or β-MnO2 are found in a number of samples of manganese ores.

An X-ray investigation of some rare-earth silicates: cerite, lessingite, beckelite, britholite, and stillwellite

1957 ◽  
Vol 31 (237) ◽  
pp. 455-468 ◽  
Author(s):  
P. Gay
Keyword(s):  
Rare Earth ◽  
New Mineral ◽  
Hexagonal Cell ◽  
Space Group ◽  
X Ray ◽  
Ideal Formula ◽  
Dimensional Approximation ◽  
Cell Dimensions ◽  
Diffraction Patterns ◽  
Probable Space

SummaryAn X-ray study of a number of rare-earth silicates has been carried out; single-crystal and powder data are presented.It is found that cerites can contain up to at least 6 % CaO without disruption of the structure, which is trigonal with probable space-group P321 etc. The cell dimensions are a ca. 10·8 Å., c ca. 37–38 Å., although there is a strong pseudo-cell with halved c-axis. An ideal formula (Ca,Ln†)3Si2(O,OH,F)9 is proposed for this series.Lessingite and beckelite can be regarded chemically as lime-rich members of this cerite series. They do not, however, have the same crystal structure as cerite; their diffraction patterns are very similar to that of britholite, and indicate a structure dimensionally comparable with apatite. For a hexagonal cell, the dimensions are a ca. 9·7 Å., c ca. 7·1 Å., with probable space-group P63, &c. An ideal formula (Ca,Ln)2(Si,Al,P)(O,OH,F)5 is proposed for this series. Marked biaxial optical properties suggest that the structure may be truly orthorhombic, with a very close dimensional approximation to a hexagonal cell.The new mineral, stillwellite, is unrelated to either of these series. It is trigonal with cell dimensions a ca. 6·9 Å., c ca. 6·7 Å., with probable space-group P3112. An ideal formula (Ca,Ln)(Si,Al,P)B(O,OH,F)5 suggested by previous work is confirmed.

The identity of ‘eggonite’ with sterrettite

1941 ◽  
Vol 26 (175) ◽  
pp. 131-133 ◽  
Author(s):  
F. A. Bannister
Keyword(s):  
British Museum ◽  
New Mineral ◽  
Aluminium Phosphate ◽  
X Ray ◽  
Phosphate Mineral ◽  
Cell Dimensions

During the X-ray study of a new phosphate mineral, not yet published, the usual comparison was made with cell-side measuremerits of related minerals. One of these is ‘eggonite’, a rare hydrous aluminium phosphate said to occur on silver ores at Felsőbánya, Hungary. Rotation photographs of ‘eggonite’ are different from those of the new mineral, but yielded dimensions close to those of sterrettite, a new mineral from Fairfield, Utah, described last year by Larsen and Montgomery. These authors generously presented a specimen of sterrettite to the British Museum, and rotation photographs taken in the Mineral Department not only give cell-dimensions close to those published but also identical with those of ‘eggonite’. A brief account of this identification is now given not only to justify abandoning the mineral name ‘eggonite’, but also to place on record a European occurrence of a rare mineral so far described from only one American locality.

Drugmanite, Pb2(Fe3+,Al) (PO4)2(OH) · H2O, a new mineral from Richelle, Belgium

1979 ◽  
Vol 43 (328) ◽  
pp. 463-467 ◽  
Author(s):  
R. Van Tassel ◽  
A.-M. Fransolet ◽  
K. Abraham
Keyword(s):  
Refractive Index ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Axial Plane ◽  
Powder Pattern ◽  
New Mineral ◽  
Space Group ◽  
X Ray ◽  
Reflectance Measurements

SummaryDrugmanite occurs as rare colourless transparent platy crystals, up to 0.2 mm, aggregated in bunches, in vugs of a mineralized and silicified limestone. Hardness < 6. Crystals monoclinic, forms {001} {110}, parameters from indexed X-ray powder pattern (and monocrystal measurements): a = 11.110 (11.111) Å, b = 7.976 (7.986), c = 4.644 (4.643), β = 90°18′ (90°.41°). Space group P21/a with Z = 2 giving Dcalc = 5.55. Strongest lines are 4.63 Å (9), 3.752 (IO), 3.350 (8), 3.247 (8), 2.912 (9). Mean refractive index 1.88 from reflectance measurements. Strong dispersion r < v, optic axial plane // (olo), 2Vα = 33±2°. Electron microprobe analysis gave P 8.89, Al 0.85, Fe 6.19, Pb 59.76%, leading to Pb4.02 Al0.45)P4.00O17.02·3H2O or Pb2 (Al0.22) (PO4)2 (OH)·H2O. Associated minerals are pyromorphite, anglesite, corkite and phosphosiderite. Named for J. Drugman, Belgian mineralogist (1875–1950).

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