Pseudomesolite is mesolite

1985 ◽  
Vol 49 (350) ◽  
pp. 103-105 ◽  
Author(s):  
Rab Nawaz ◽  
John F. Malone ◽  
Victor K. Din
Keyword(s):  
Chemical Analysis ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
X Ray ◽  
Unit Cells ◽  
Wet Chemical

AbstractPseudomesolite from Carlton Peak, described by Winchell (1900), is shown to be mesolite by means of chemical and X-ray data. A proposal to this effect has been accepted by the International Mineralogical Association's Commission on New Minerals and Mineral Names. Electron microprobe analysis revealed variations in the composition of pseudomesolite and showed the presence of faroelite. The X-ray powder diffraction pattern is similar to that of mesolite. Single-crystal Weissenberg photographs showed a twinning intergrowth which is explained by a 90° rotation of 50% of the unit cells about the c-axis, so that the a- and b-axes of rotated cells coincide with the b- and a-axes respectively of the unrotated cells. This twinning can not be detected optically. Mesolite has recently been proved to be orthorhombic, contrary to the long-held view that it is monoclinic.Pseudomesolite from Oregon is also shown to be mesolite by single crystal Weissenberg photographs. A wet chemical analysis shows this material to be extremely silica-rich.

Nature of dioctahedral micas in Spanish red soils

Clay Minerals ◽  
1997 ◽  
Vol 32 (1) ◽  
pp. 107-121 ◽  
Author(s):  
J. M. Martin-Garcia ◽  
G. Delgado ◽  
M. Sanchez-Maranon ◽  
J. F. Parraga ◽  
R. Delgado
Keyword(s):  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
X Ray ◽  
Red Soils ◽  
Mineral Phases ◽  
Composition And Structure ◽  
Structural Formulae ◽  
Coarse Gravel

AbstractStructural formulae and other crystallochemical parameters were used to study different species of dioctahedral micas in clay and coarse gravel fractions of horizons from a red soil (Ultic Haploxeralf) in southern Spain. Mineralogical analyses using X-ray powder diffraction, and measurements of theb0parameter revealed dioctahedral micas, illite and paragonite. Structural formulae established from electron microprobe analysis and energy dispersive X-ray analysis showed the illites to be K mica related in elemental composition and structure to muscovite and phengite. The paragonites were found to be closer to ideal mica. Structural formulae for Na-K dioctahedral micas were obtained with crystallochemical characteristics intermediate between those of Na micas and K micas. The possibilty of these micas representing individual mineral phases or intergrowths of Na and K micas is discussed. In the soil profile, micas from the Bt horizon showed the largest crystallochemical changes induced by pedogenesis.

Monoclinic structure and nonstoichiometry of `KAlSiO4-O1'

2013 ◽  
Vol 69 (4) ◽  
pp. 334-336 ◽  
Author(s):  
Aleksandar Kremenović ◽  
Biljana Lazic ◽  
Hannes Krüger ◽  
Martina Tribus ◽  
Predrag Vulić
Keyword(s):  
Single Crystal ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
Flux Method ◽  
X Ray ◽  
Derivatives Of ◽  
Aluminium Silicate

Crystals of KAlSiO4-O1(potassium aluminium silicate) were synthesized using a flux method and analysed utilizing single-crystal X-ray diffraction and electron microprobe analysis. Both methods confirm that the crystals are nonstoichiometric according to K1−xAl1−xSi1+xO4withx= 0.04 (1). KAlSiO4-O1is closely related to the stuffed derivatives of tridymite, although the topology of the Si/Al-ordered framework is different. Six-membered rings of UUDDUD and UUUDDD (U = up and D = down; ratio 2:1) configurations are present in layers parallel to theabplane. In contrast, the framework of tridymite exhibits UDUDUD rings. The crystals are affected by inversion, pseudo-orthorhombic and pseudo-hexagonal twinning.

Arsenoflorencite-(Ce): a new arsenate mineral from Australia

1987 ◽  
Vol 51 (362) ◽  
pp. 605-609 ◽  
Author(s):  
E. H. Nickel ◽  
J. E. Temperly
Keyword(s):  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
South Australia ◽  
Stream Sediments ◽  
Space Group ◽  
X Ray ◽  
Conchoidal Fracture ◽  
Simplified Formula

AbstractArsenoflorencite-(Ce) has been found at three localities in Australia—two in South Australia, and one in Queensland. It occurs as colourless to light brown scalenohedral crystals and crystal fragments in stream sediments. Electron microprobe analysis gave Ce2O3 12.97, La2O3 8.62, Pr2O3 3.35, Nd2O3 2.40, Gd2O3 1.38, Sm2O3 0.38, SrO 1.99, Al2O3 28.75, As2O5 27.02, P2O5 4.68, SO3 1.21%; calc, H2O 9.36%; total 102.11%. The simplified formula is REAl3(AsO4)2(OH)6, with Ce as the dominant RE element. Arsenoflorencite-(Ce) is rhombohedral, has space group R3m with αhex. 7.029 and chex. 16.517 Å, and Z = 3. Strongest X-ray powder diffraction lines are: 3.513(6)(110), 2.963(10)(113), 2.201(4)(107), 1.905(5)(303) and 1.753 Å(4)(220). Density is 4.096 (meas.) and 4.091 (calc.) g/cm3. Hardness is VHN10 170. Arsenoflorencite-(Ce) is brittle, breaks with a conchoidal fracture, and has no perceptible cleavage. The mineral is colourless in transmitted light, uniaxial positive, and has ω 1.739 and ɛ 1.745 (λ = 589 nm). Arsenoflorencite-(Ce) is the arsenate analogue of florencite-(Ce), and the name was chosen to indicate this relationship.

Chenite, Pb4Cu(SO4)2(OH)6, a new mineral, from Leadhills, Scotland

1986 ◽  
Vol 50 (355) ◽  
pp. 129-135 ◽  
Author(s):  
W. H. Paar ◽  
Kurt Mereiter ◽  
R. S. W. Braithwaite ◽  
Paul Keller ◽  
P. J. Dunn
Keyword(s):  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Refractive Indices ◽  
New Mineral ◽  
Secondary Mineral ◽  
X Ray ◽  
Infra Red ◽  
The Ideal

AbstractChenite, a new lead-copper secondary mineral, has been found on specimens from the Leadhills area, Scotland. It is associated with caledonite, linarite, leadhillite, susannite, and other species, on oxidized galena with chalcopyrite. Electron microprobe analysis yielded PbO 74.5, CuO 7.8, SO3 13.3, H2O 4.4 (by difference), sum = 100 wt. %. The empirical formula (based on 14 oxygens) is Pb3.98Cu1.17S1.98O14H5.82; the ideal formula is Pb4Cu(SO4)2(OH)6, which requires PbO 75.2, CuO 6.7, SO3 13.5, H2O 4.6, sum = 100 wt. %.Infra-red spectroscopy showed the presence of only and OH− ions, with no H2O.Chenite is triclinic, P1 or P̄, with a = 5.791(1), b = 7.940(1), c = 7.976(1) Å, α = 112.02(1), β = 97.73(1), γ = 100.45(1)°, V = 326.0 Å3, Z = 1. The strongest lines in the X-ray powder diffraction pattern (d, I/Io, hkl) are: 5.55, 7, 100; 4.32, 6, 11; 3.60, 10 002; 3.41, 9, 10; 3.30, 5, 02; 3.00, 5, 111; 2.80, 7, 12; 2.07, 6, 211/21/13; 1.778, 5, 3/23.Chenite forms minute, singly terminated, transparent to translucent sky-blue crystals from 0.1 to over 1 mm long, elongated approximately [032]. Twenty different forms (pinacoids) have been identified on the four crystals studied. A good cleavage on {100}, and traces of a second on {001}, can be observed. Optically, chenite is biaxial negative, 2 V(measured) = 67±1°, 2 V(calc.) = 68° (Na). The refractive indices are α 1.871±0.005, β 1.909±0.005, γ 1.927±0.005 (Na). Dispersion is strong, r≫v. The mineral is weakly pleochroic. H (Mohs) ∼ 2½. D = 5.98, and calculated Dx = 6.044 g cm−3.

New data on georgiadesite

1983 ◽  
Vol 47 (343) ◽  
pp. 219-220 ◽  
Author(s):  
Roland C. Rouse ◽  
Pete J. Dunn
Keyword(s):  
Single Crystal ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray

AbstractThe chemistry and crystallography of type georgiadesite from Laurion, Greece, have been reexamined using electron microprobe analysis along with powder and single-crystal X-ray diffraction. Georgiadesite is monoclinic, P21/c, with a = 13.803(10), b = 7.910(2), c = 10.812(4) Å, and β = 102.68(3)°. No twinning was observed. The probable chemical formula is either Pb16(AsO4)4Cl14O2(OH)2 or Pb16(AsO4)4Cl14(OH)6. The calculated densities for these formulae are 6.39 and 6.44 g/cm3, respectively, compared to a measured value of 6.3 + 0.3 g/cm3

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