DOCSLIB.ORG

Synthesis of Benstonite at Room Temperature

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Synthesis of Benstonite at Room Temperature American Mineralogist, Volume 58, pages 347-342, 1973 Synthesisof Benstoniteat Room Temperature Wnrrena C. Hooo, aNo pErpn F. Srenr, Department ol Geology, Southerrc Illirwis (Jniaersity, Carbon:dale,Illinois 6290I Abstract Benstonite;MgCaoBae(COr)'", has been synthesizedat room temperatureby mixing a solu- tion containing 12.5ml of 0.2 molar MgClz, 12.5ml of 0.2 molar BaCl", and 5.0 ml of 0.1 molar CaCl: with 25 ml of 0.5 molar sodium carbonate solution and allowing the precipitate to age in contact with the remaining solution for two weeks. During the course of an investigationof mineral and a smear mount was made of the precipitate. relationshipsin the systemBa-Mg-Ca-CO3 in aque- The material was identified as benstoniteby X-ray ous solutionat room temperature,the mineral ben- diffraction. All of the more intensediffraction peaks, stonitewas synthesized.This mineralhas not previ- as well as many of the minor ones,reported by Lipp ously been synthesized, so we report here the mann (1962) and Sundius(1964) are presenton condition under which it was formed. diffraction traces made from the artificial material Benstonite was first described by Lippmann (Table 1). Intensitiesof the peaks are in general (1,961a,l96lb, 1962) from the barite mine near agreementwith thosereported by Lippman. No other Magret Cove,Arkansas. ft has sincebeen identified peaks are presenton the diffractometertrace, so the at Langban,Sweden (Sundius, 1964; Moore, I97O) benstonite seems to be present in relatively pure and at the Minerva Mine near Cave-in-Rock,Illinois forms. (White and Jarosewich,1970). The chemicalfor- The composition of the solution and the method mula is not yet known with certainty. Lippmann of precipitation of the mineral is very similar to (1962) suggestedeither (Ca,Mg,Mn)7(Ba,Sr)6that used in a study of Mg-Ba-CO3 in aqueous (COr)r* or possiblyMgCa6Ba6(COr)rr. The mate- solution (Hood and Steidl,in preparation),the only rial from Illinois contains2.1 wt percent magnesium, differencebeing the presenceof calcium and a longer which correspondsvery closely to one magnesium agingperiod. The magnesium,barium, and carbonate per formula, so White and Jarosewich (1970) concentrations are such that norsethite (BaMg stronglysuggest that magnesiumis an essentialcon- (COr)r) plus witherite would have formed in the stituent and does not substitutefor calcium. In view absenceof calcium. The presenceof calcium allowed of the composition of the solution from which we the formation of benstonite rather than norsethite synthesizedthe mineral, we are inclined to agreewith this interpretation. and perhapsexplains the apparentabsence of norse- Illinois fluorspar district. The Benstonitewas precipitatedfrom aqueoussolution thite in the Southern pres- by first mixing togetherI2.5 ml of 0.2 molar MgCl2, assemblagewitherite, benstonite,and calcite is (White 12.5ml of 0.2 molar BaCl2,and 5.0 ml of 0.1 molar ent in the Minerva Mine and Jarosewich, CaClz. To this cation-bearingsolution 25 ml of 0.5 1970) and the assemblagebenstonite, barite, and molar sodium carbonate solution was added while calcite is presentin the Magnet Cove locality (Lipp- stirring with a magnetic stirrer. A white precipitate mann, 1962). Calcite, benstonite,norsethite, and formed immediately. After approximately two min- barytocalcite(BaCa(COg)s) have all beenreported utes of stirring, the beaker containing the solution from Langban, Sweden(Moore, 1,970).Relations and suspendedprecipitate was covered and allowed amongthese various mineralsare not clear. Study of to sit for two weeksat room temperature.At the end the system Ba-Mg-Ca-COsat room temperatureis of this time, the aqueoussolution was decantedoff continuing in this laboratory. 341 342 MINERALOGICAL NOTES Tlsrn l. X-ray Powder Data for Natural and Artificial Benstonite MagnetCove, Ark. Lanaban,Srreden Arti fi cral d (A) d (i) d (A) 9.21 3 7.63 3 5.83 2 5.28 3 534 5 4.57 3 4.19 t6 421 50 4.21 l3 392 67 3.92 38'l 3.89 60 3.80 3.60 9 3 .60 6 3.45 4 335 10 3.37 40 3.37 3 309 95 307 100 3 l0 100 298 l 300 60 3.01 1 289 I 2.755 3 2.637 I ?.62 t0 2.557 2 2.55 3 2.536 28 2 -52 2.52 50 2 .495 I 2.46 1 2.445 9 245 2.38 2 2.327 2 2.28 I 2.233 5 2.217 l0 221 20 2.19 1? 2.19 4 2.15 1 215 2.123 23 2.1',| ?.12 45 2.il3 4 2 097 4 2.042 2 2.03 2.006 3 I 994 3 I 973 1.957 i0 t98 23 I 945 il I .948 40 1.96 20 1.905 17 1 902 50 1.92 25 1 .886 5 'I1.863 4'I I 869 40 .834 1.757 I 1.764 1.746 l 'I1 728 2'l .698 'I 1 692 1 691 ']1 .670 I 664 I 1.65'] 3 'I1.645 I .630 7 I .630 t8 1.616 ? I .620 t0 1.626 7 1.547 6 I .548 30 1.556 17 References from the barite deposit in Hot Spring County, Arkansas. Amer. Mineral. 47, 585-598. Moonr, P. B. ( 1970) Mineralogy and chemistry of LtrrlreN, F. (196la) Uber ein barium-calciumkarbonataus Langban-type deposits in Bergslagen, Sweden. Mineral. Hot Spring County, Arkansas (abstr.). Fort. Mineral. Record, l, 154-172. 39.81. SuNorus, N. (1964) Carbonatesin the manganeseores at (1961b) Benstonite,Ca"Bau(CO.)o, ein neues min- Langban. Ark. Mineral. GeoI. 4, 279285. eral. D ie Naturwissenschaften, 4E, 550-55 1. Wnrra, J. S., lNo E. Jlnosrwrcn (1970) Secondoccurrence (1962) Benstonite, CazBao(COr)o,a new mineral of benstonite.Mineral. Record, l, l4Ll4l..
Load more

Recommended publications
  • Barite (Barium)
    Barite (Barium) Chapter D of Critical Mineral Resources of the United States—Economic and Environmental Geology and Prospects for Future Supply Professional Paper 1802–D U.S. Department of the Interior U.S. Geological Survey Periodic Table of Elements 1A 8A 1 2 hydrogen helium 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 lithium beryllium boron carbon nitrogen oxygen fluorine neon 6.94 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 13 14 15 16 17 18 sodium magnesium aluminum silicon phosphorus sulfur chlorine argon 22.99 24.31 3B 4B 5B 6B 7B 8B 11B 12B 26.98 28.09 30.97 32.06 35.45 39.95 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.39 69.72 72.64 74.92 78.96 79.90 83.79 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 85.47 87.62 88.91 91.22 92.91 95.96 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 cesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 132.9 137.3 178.5 180.9 183.9 186.2 190.2 192.2 195.1 197.0 200.5 204.4 207.2 209.0 (209) (210)(222) 87 88 104 105 106 107 108 109 110 111 112 113 114 115 116
    [Show full text]
  • Infrare D Transmission Spectra of Carbonate Minerals
    Infrare d Transmission Spectra of Carbonate Mineral s THE NATURAL HISTORY MUSEUM Infrare d Transmission Spectra of Carbonate Mineral s G. C. Jones Department of Mineralogy The Natural History Museum London, UK and B. Jackson Department of Geology Royal Museum of Scotland Edinburgh, UK A collaborative project of The Natural History Museum and National Museums of Scotland E3 SPRINGER-SCIENCE+BUSINESS MEDIA, B.V. Firs t editio n 1 993 © 1993 Springer Science+Business Media Dordrecht Originally published by Chapman & Hall in 1993 Softcover reprint of the hardcover 1st edition 1993 Typese t at the Natura l Histor y Museu m ISBN 978-94-010-4940-5 ISBN 978-94-011-2120-0 (eBook) DOI 10.1007/978-94-011-2120-0 Apar t fro m any fair dealin g for the purpose s of researc h or privat e study , or criticis m or review , as permitte d unde r the UK Copyrigh t Design s and Patent s Act , 1988, thi s publicatio n may not be reproduced , stored , or transmitted , in any for m or by any means , withou t the prio r permissio n in writin g of the publishers , or in the case of reprographi c reproductio n onl y in accordanc e wit h the term s of the licence s issue d by the Copyrigh t Licensin g Agenc y in the UK, or in accordanc e wit h the term s of licence s issue d by the appropriat e Reproductio n Right s Organizatio n outsid e the UK. Enquirie s concernin g reproductio n outsid e the term s state d here shoul d be sent to the publisher s at the Londo n addres s printe d on thi s page.
    [Show full text]
  • Thirty-Fourth List of New Mineral Names
    MINERALOGICAL MAGAZINE, DECEMBER 1986, VOL. 50, PP. 741-61 Thirty-fourth list of new mineral names E. E. FEJER Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD THE present list contains 181 entries. Of these 148 are Alacranite. V. I. Popova, V. A. Popov, A. Clark, valid species, most of which have been approved by the V. O. Polyakov, and S. E. Borisovskii, 1986. Zap. IMA Commission on New Minerals and Mineral Names, 115, 360. First found at Alacran, Pampa Larga, 17 are misspellings or erroneous transliterations, 9 are Chile by A. H. Clark in 1970 (rejected by IMA names published without IMA approval, 4 are variety because of insufficient data), then in 1980 at the names, 2 are spelling corrections, and one is a name applied to gem material. As in previous lists, contractions caldera of Uzon volcano, Kamchatka, USSR, as are used for the names of frequently cited journals and yellowish orange equant crystals up to 0.5 ram, other publications are abbreviated in italic. sometimes flattened on {100} with {100}, {111}, {ill}, and {110} faces, adamantine to greasy Abhurite. J. J. Matzko, H. T. Evans Jr., M. E. Mrose, lustre, poor {100} cleavage, brittle, H 1 Mono- and P. Aruscavage, 1985. C.M. 23, 233. At a clinic, P2/c, a 9.89(2), b 9.73(2), c 9.13(1) A, depth c.35 m, in an arm of the Red Sea, known as fl 101.84(5) ~ Z = 2; Dobs. 3.43(5), D~alr 3.43; Sharm Abhur, c.30 km north of Jiddah, Saudi reflectances and microhardness given.
    [Show full text]
  • Daqingshanite-(Ce) (Sr, Ca, Ba)3(Ce, La)(PO4)(CO3)3−X(OH, F)X C 2001-2005 Mineral Data Publishing, Version 1
    Daqingshanite-(Ce) (Sr, Ca, Ba)3(Ce, La)(PO4)(CO3)3−x(OH, F)x c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Hexagonal. Point Group: 3m (probable). As subhedral to rounded platy crystals, may be crudely rhombohedral, to 3 mm, in aggregates. Twinning: Complex polysynthetic twinning observed in some material. Physical Properties: Cleavage: Perfect on {1011}. Fracture: Conchoidal. Hardness = n.d. VHN = 335 (20 g load). D(meas.) = 3.81 D(calc.) = 3.71 Optical Properties: Semitransparent. Color: Pale yellow to nearly white; colorless in thin section. Streak: White. Luster: Vitreous to greasy. Optical Class: Uniaxial (–). ω = 1.708 = 1.609 Cell Data: Space Group: R3m, R3m, or R32. a = 10.058–10.073 c = 9.225–9.234 Z = 3 X-ray Powder Pattern: Bayan Obo deposit, China. 3.16 (10), 2.52 (7), 3.95 (6), 2.040 (6), 1.941 (6), 2.110 (5), 1.895 (4) Chemistry: (1) (2) (1) (2) (1) (2) P2O5 11.73 10.50 Fe2O3 0.21 K2O 0.03 CO2 16.19 n.d. MnO 0.02 F 0.80 0.29 ThO2 0.04 < 0.22 MgO 0.72 < 0.12 Cl 0.10 + Al2O3 0.18 < 0.12 CaO 6.17 0.94 H2O 0.68 n.d. La2O3 7.88 10.22 SrO 26.10 41.82 −O=F2 0.34 Ce2O3 10.16 12.24 BaO 15.98 4.57 Total [99.376] RE2O3 2.696 < 3.36 Na2O 0.13 < 0.16 (1) Bayan Obo deposit, China; CO2 and H2O by gas chromatography, original total given as 99.20%; RE2O3 =Pr6O11 0.70%, Nd2O3 1.59%, Sm2O3 0.106%, Eu2O3 0.02%, Gd2O3 0.12%, Tb4O7 0.05%, Dy2O3 0.03%, Ho2O3 0.03%, Er2O3 0.01%, Tm2O3 0.01%, Yb2O3 0.02%, Lu2O3 0.01%; corresponds to (Sr1.52Ca0.67Ba0.63Mg0.11Na0.03)Σ=2.96(Ce0.37La0.29RE0.10Al0.02 3+ Fe0.02)Σ=0.80(PO4)1.00(CO3)2.23[(OH)0.46F0.26]Σ=0.72.
    [Show full text]
  • NOTICE New Mineratr Names Has Been Prepared by Michael
    NOTICE New Mineratr Names has been prepared by Michael Fleischer for many years with extraordinary coverage and critical evaluation, and remains one of the most important sections ol The Americon Mineral,ogist. Dr. Fleischer con- tinues to find the task enjoyable but increasingly burdensome. This is a call for volunteers to assist him in combing and reviewing the literature for clescrip- tions of new minerals and new mineral data Mineralogists interested, please contact Dr. M. Fleischer, U, S. Geological Survey, Washington 25, D. C., and specify the language(s) and journals you can ancl are willing to cover. Es- pecially helpful would be the services of three good mineralogists to cover Minerologicol Magazine, Bulletin Soci.6t6 Franqaise Minlralogie, and Neues Jahrbuch J* Minerologie etc., Monatshefte NEW MINERAL NAMES Farringtonite E. R' DurnnsNa aNo s. K. Rov. A new phosphate mineral from the springwater pallasite: Geocltim.et Cosmocltim.Acta,24, 198 205 (1961). The mineral was found in the springn'ater pallasite, from near Springwater, Sas- katchewan. rt occurs as colorless to wax-white to yellon' material peripheral to olivine nodules. The meteorite also contains metallic iron (kamacite) ancl troilite. Spectrographic analyses were made on two 25 mg. samples; the first rn'ascleaned magnetically, the second by gravity separation in a centrifuge as we1l. These gave: pror 37.6+0.6,49.7 + 1.0;MgO 49.2+O.2,4t.6I1.3; SiO, 11.1+0.2,2.9 +0.1; Fe 5.4+0.1,3.7 ,,quite +0.2ok. The final content of metallic iron in the samples was negligible,,; the Fe reported must be present as FeO or FezO: or both.
    [Show full text]
  • Fluid Inclusions in Fibrous and Octahedrally-Grown Diamonds
    FLUID INCLUSIONS IN FIBROUS AND OCTAHEDRALLY-GROWN DIAMONDS by Evan Mathew Smith A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in The Faculty of Graduate and Postdoctoral Studies (Geological Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) March 2014 © Evan Mathew Smith, 2014 Abstract My thesis puts forth new models for diamond formation that explain the difference between octahedral and fibrous diamond growth, as well as the difference between octahedral diamond growth in the lithospheric and the sublithospheric mantle. Diamond growth in the mantle involves reactions between carbon-bearing fluid and the host rocks it infiltrates. This fluid is sometimes included in diamond. Fluids in dendritically-grown, fibrous diamonds from Wawa, Superior craton, were analysed in a novel way, using transmission X-ray diffraction. The technique allows bulk analysis of daughter minerals within fluid inclusions. The mineralogy, major and trace elements, Sr isotopes, volatiles, and nitrogen characteristics of the hydrous saline–high-Mg carbonatitic fluid in these Archean diamonds strongly resemble those of Phanerozoic fibrous diamonds. This implies that some mantle processes, including the formation of fibrous diamonds, can be extended unvaryingly back to 2.7 Ga. Fluid equilibrated with octahedrally-grown diamonds from the Siberian, Kaapvaal, and Congo cratons is trapped in healed fractures in the diamonds. They contain anhydrous CO2–N2 fluid inclusions with 40±4 mol% N2 and inclusions of former silicate melt that had an original N2 content of ~0.1 wt%, as shown by Raman, electron microprobe, and microthermometry analyses. The liberation of N2 from the convecting mantle is proposed to be controlled by increasing oxygen fugacity that destabilizes host phases.
    [Show full text]
  • New Mineral Names
    NEW MINERAL NAMES Mrcrrlrr Flrrscsnn Sibirskite N. N. V.rsrr,rovA, A new calcium borate, sibirskite. Zapishi Vses. Mineral'og. Obshch,9l, 4554& (1962) (in Russian). Analysis of a mixture of the mineral with calcite, a chlorite, and a little pyrite gave 5iO27.72, TiO, 0.03, L12O82.43,FeO 1.01, MgO 10.06, MnO 0.29, CaO 41.78, NarO 0.04' K2O none, CO216.72,B2O3 13.51, C 0.12,HrO- 0.36,H2O+ 6.38,S 0.48:100.93-(0: S) 0.24:100.697o. Separate analyses were made of the material soluble in acetic acid (calcite *sibirskite) and the insoluble. Recalculation indicates CaO:BzOa:HzO:2.07:1:1.02 or CauBzOr(OH)z or CaHBOa. The mineral is insoluble in boiling HzO, soluble in cold acetic or hydrochloric acid. DTA curves showed strong endothermic peaks at 870" (due to calcite) and at 430o, and a weak endothermic peak at 670" (due to chlorite). X-ray powder data by G. A. Sidorenko (19 lines) are givenl the strongest lines are 2.93 (5),2.58 (5), 1.878 (3). (The data are inadequate for comparison with the r-ray clata of Lehmann etr ol'., Zeits. onorg. allgem. Ckem. 2968, 202-203 (1958) on synthetic CaHBOa.MF). Sibirskite occurs as diamond-shaped forms of size 1.0-1.5 mm or as aggregates of irregular grains colored dark gray by chlorite. The rhombs show angles of 110" and 70". Measurements on the Federov stage show that the symmetry approximates orthorhombic. Biaxial (-); indices measured by Yu.
    [Show full text]
  • (1Eso). the Barite Rock Is Fine-Grained and Has a Gray Color Owing to Varying Amounts of Interspersedshaly Matter
    THE AMERICAN MINERALOGIST, VOL.47, MAY_JUNE, 1962 BENSTONITE, CazBa6(COr)tr,A NEW MINERAL FROM THE BARITE DEPOSIT IN HOT SPRING COUNTY, ARKANSAS Fnrrrnrcs Lrrruenw,l Mineralogische Anstohen der Uniaersildl, Gdttingen,Germany. Ansrnlcr Benstonite, (Ca,Mg,Mn)r(Ba,Sr)6(CO)s, was found at the barite mine in Hot Spring County, Arkansas, where it occurs in veins within the barite body associated with milky quartz, barite and calcite. It forms white cleavable masses which show cleavage faces up to 1 cm across.H:3-4; G 3.596 (meas.), 3.648 (calc.); good rhombohedral cleavagewith about the same angles as calcite. Uniaxial negative with o:1.690s and e:1.527. Single crystal r-ray studies revealed a rhombohedral lattice with the following characteristics: possible space groups RB or R3, the most probable being R3 because of -the symmetry of the CO3-groupand the available equipoints; hexagonal, o:18.28*0.01 A, c:8.67IO.02; rhombohedral, a,t:10.944, a:113.3o; volume 2509 Aa ftex.;, cell contents:3 [CazBao (COa)ul in the hexagonal unit. The index of the cleavageface is [3142] or [4132]. The hexagonal indices of the strongest r-ray reflections satisfy the relation Trzaftzlhk :13n, and they may be transformed to the indices of calcite reflections. The resulting "calcite-ceil" of benstonite has o!:a/t4i3:5.0? A, C':2c:17.34 A; volume 386.0 A3; calcite: a:4.990 A; c:17.06 A; volume 367.80 A3. Benstonite therefore has a structure which may be described as a superstructure derived from the calcite configuration.
    [Show full text]
  • Barytocalcite Baca(CO3)2 C 2001-2005 Mineral Data Publishing, Version 1
    Barytocalcite BaCa(CO3)2 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Monoclinic. Point Group: 2/m. Typically as elongated crystals, short to long prismatic and striated parallel [101], to 5 cm, or equant, showing large {100}, {111}, {131}, {210}, minor {001},{110}, {101}; may be massive, cleavable. Physical Properties: Cleavage: On {210}, perfect; on {001}, imperfect. Fracture: Uneven to subconchoidal. Hardness = 3.5–4 D(meas.) = 3.66–3.71 D(calc.) = 3.72 Pale yellowish to red fluorescence under SW and LW UV. Optical Properties: Transparent to translucent. Color: Colorless to white, pale gray, bright to pale green, pale yellow; colorless in transmitted light. Luster: Vitreous to resinous. Optical Class: Biaxial (–). Orientation: Z = b; X ∧ c =64◦; Y ∧ c = –26◦. Dispersion: r> v, weak. α = 1.525 β = 1.684 γ = 1.686 2V(meas.) = 15◦ Cell Data: Space Group: P 21/m. a = 8.092(1) b = 5.2344(6) c = 6.544(1) β = 106.05(1)◦ Z=2 X-ray Powder Pattern: Alston, England. (ICDD 15-285). 3.125 (100), 3.140 (90), 4.018 (40), 4.345 (25), 2.157 (25), 2.512 (20), 2.379 (20) Chemistry: (1) (2) CO2 29.95 29.59 MgO 0.50 CaO 18.75 18.85 SrO 1.81 BaO 48.92 51.56 Total 99.93 100.00 (1) Vuoriyarvi massif, Russia; corresponds to Ba0.92Ca1.03Sr0.08Mg0.03(CO3)2.00. (2) BaCa(CO3)2. Polymorphism & Series: Trimorphous with alstonite and paralstonite. Occurrence: A relatively uncommon accessory mineral in metallic veins, formed by reaction of hydrothermal fluids with limestone; however it may be the dominant barium-bearing species; rarely in carbonatites and Alpine veins.
    [Show full text]
  • EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite
    Hindawi Publishing Corporation Advances in Condensed Matter Physics Volume 2008, Article ID 175862, 8 pages doi:10.1155/2008/175862 Research Article EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite S. Lakshmi Reddy,1 R. L. Frost,2 G. Sowjanya,1 N. C. G. Reddy,3 G. Siva Reddy,3 andB.J.Reddy2 1 Department of Physics, S.V.D. College, Kadapa 516003, India 2 Inorganic Materials Research Program, Queensland University of Technology, 2 George Street, Brisbane, GPO Box 2434, Queensland 4001, Australia 3 Department of Chemistry, Yogi Vemana University, Kadapa 516003, India Correspondence should be addressed to R. L. Frost, [email protected] Received 17 June 2008; Accepted 21 October 2008 Recommended by David Huber Dolomite mineral samples having white and light green colors of Indian origin have been characterized by EPR, optical, and NIR spectroscopy. The optical spectrum exhibits a number of electronic bands due to presence of Fe(III) ions in the mineral. From EPR studies, the parameters of g for Fe(III) and g, A,andD for Mn(II) are evaluated and the data confirm that the ions are in distorted octahedron. Optical absorption studies reveal that Fe(III) is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules. Thus EPR and optical absorption spectral studies have proven useful for the study of the solid state chemistry of dolomite. Copyright © 2008 S. Lakshmi Reddy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
    [Show full text]
  • Alstonite Baca(CO3)2 C 2001-2005 Mineral Data Publishing, Version 1
    Alstonite BaCa(CO3)2 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Triclinic, pseudo-orthorhombic. Point Group: 1or1. Steep pseudohexagonal dipyramids bounded by pseudohexagonal prisms, to 6 mm, striated strongly ⊥ pseudohexagonal [0001] and commonly exhibiting a medial re-entrant k pseudohexagonal [0001]. Twinning: Common on pseudo-orthorhombic {110} and {310}, forming pseudohexagonal groups. Physical Properties: Cleavage: On pseudo-orthorhombic {110}, imperfect. Fracture: Uneven. Hardness = 4–4.5 D(meas.) = 3.707(4) D(calc.) = 3.69 Fluoresces yellow under SW and LW UV. Optical Properties: Transparent to translucent. Color: Colorless to snow-white; also pale gray, pale cream, pink to pale rose-red, which may fade on exposure to light; colorless in transmitted light, showing six or twelve domains. Streak: White. Luster: Vitreous. Optical Class: Biaxial (–). Orientation: X = c; Y = a; Z = b. Dispersion: r> v,weak. α = 1.526 β = 1.671 γ = 1.672 2V(meas.) = 6◦ Cell Data: Space Group: C1orC1. a = 30.14 b = 17.40 c = 6.12 α =90◦ β =90◦ γ =90◦ Z=24 X-ray Powder Pattern: Alston, England; essentially identical to paralstonite. 3.55 (100), 2.507 (35), 2.050 (23), 1.941 (19), 1.846 (15), 2.835 (10), 1.589 (8) Chemistry: (1) (2) CO2 29.41 29.59 CaO 17.60 18.85 SrO 4.25 BaO 48.54 51.56 Total 99.80 100.00 (1) Alston, England. (2) CaBa(CO3)2. Polymorphism & Series: Trimorphous with barytocalcite and paralstonite. Occurrence: Typically in low-temperature hydrothermal Pb–Zn deposits; rare in carbonatites. Association: Calcite, barite, ankerite, siderite, benstonite, galena, sphalerite, pyrite, quartz.
    [Show full text]
  • Subsolidus Phase Relations in Aragonite-Type Carbonates. Lll. The
    American Mineralogist, Volume 58, pages 979-985, 1973 SubsolidusPhase Relations in Aragonite-typeCarbonates. lll. The SystemsMgCO'-CaCO,-BaCOB, MgOO,-CaGO,-SrCO,, and MgCO,-SrCO,-BaCO, Wrtr,reu R. BnrcE Department ol Earth and Planeta:rySciences, Uniuersity of Pittsburgh at lohttstown, Iohnstown, Pennsylaania 15901 Lurn L. Y. CnaNc Department ol Geology, Miqmi Uniuersity, Oxford, Ohio 45056 Abstract Subsolidus phase relations in the three ternary systems were studied at 650"C and at both 5 and 15 kbar using high-pressure, opposed-anvil apparatus. Phases found in the systems, in addition to the end members, are dolomite (MgCa(COa),), norsethite (MgBa(COo),), MgSr(CO")a and two forms of CaBa(COs),, a monoclinic barytocalcite and a rhombohedral form with disordered calcite structure. In the system MgCOrCaCOrBaCO", both norsethite and disordered calcite have detectable ranges of solid solution at 650'C and 5 kbar, and six two-phase areas and four three-phase triangles are observed. In the system MgCO-CaCO-SrCOI, a complete series of solid solution along the join MgCa(CO")-MgSr(COg)z and a significantregion of calcite-typesolid solution exist at 650"C and 5 kbar, whereas at 650'C and 15 kbar, aragonite is the stable form of CaCO" and forms a complete series of solid solution with SrCO". Two complete solid solution series, SrCO-BaCO* and MgSr(CO")-MgBa(COo)a were found in the system MgCO- SrCO-BaCOa, and the system is represented by two large immiscibility gaps between the two solid solution series and between the dolomite seriesand MgCOa. Introduction Experimental Procedures As the third part of a study on the subsolidus Starting materials used were Baker analyzedrea- phase relations in aragonite-type carbonates, the gent grade CaCO3,SrCO3, BaCOs, and basic mag- systems MgCO3-CaCO3-BaCO3,MgCO3-CaCO3- nesium carbonate.The MgCO3 was prepared by SrCOs, and MgCOB-SrCOs-BaCOswere investi- hydrothermallytreating the basic magnesiumcar- gated at 650"C and two pressures,5 and 15 kbar.
    [Show full text]