DOCSLIB.ORG

Phase Equilibria and Thermodynamic Properties of Minerals in the Beo

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Phase Equilibria and Thermodynamic Properties of Minerals in the Beo American Mineralogist, Volwne 71, pages 277-300, 1986 Phaseequilibria and thermodynamic properties of mineralsin the BeO-AlrO3-SiO2-H2O(BASH) system,with petrologicapplications Mlnx D. B.qnroN Department of Earth and SpaceSciences, University of California, Los Angeles,Los Angeles,California 90024 Ansrru,cr The phase relations and thermodynamic properties of behoite (Be(OH)r), bertrandite (BeoSirOr(OH)J, beryl (BerAlrSiuO,r),bromellite (BeO), chrysoberyl (BeAl,Oo), euclase (BeAlSiOo(OH)),and phenakite (BerSiOo)have been quantitatively evaluatedfrom a com- bination of new phase-equilibrium, solubility, calorimetric, and volumetric measurements and with data from the literature. The resulting thermodynamic model is consistentwith natural low-variance assemblagesand can be used to interpret many beryllium-mineral occurTences. Reversedhigh-pressure solid-media experimentslocated the positions of four reactions: BerAlrSiuO,,: BeAlrOo * BerSiOo+ 5SiO, (dry) 20BeAlSiOo(OH): 3BerAlrsi6or8+ TBeAlrOo+ 2BerSiOn+ l0HrO 4BeAlSiOo(OH)+ 2SiOr: BerAlrSiuO,,+ BeAlrOo+ 2H2O BerAlrSiuO,,+ 2AlrSiOs : 3BeAlrOa + 8SiO, (water saturated). Aqueous silica concentrationswere determined by reversedexperiments at I kbar for the following sevenreactions: 2BeO + H4SiO4: BerSiOo+ 2H2O 4BeO + 2HoSiOo: BeoSirO'(OH),+ 3HrO BeAlrOo* BerSiOo+ 5H4Sio4: Be3AlrSiuOr8+ loHro 3BeAlrOo+ 8H4SiO4: BerAlrSiuOrs+ 2AlrSiO5+ l6HrO 3BerSiOo+ 2AlrSiO5+ 7H4SiO4: 2BerAlrSiuOr8+ l4H2o aBeAlsioloH) + Bersio4 + 7H4sio4:2BerAlrsiuors + 14Hro 2BeAlrOo+ BerSiOo+ 3H4SiOo: 4BeAlSiOr(OH)+ 4HrO. The results of these experiments were combined with the heat capacitiesand entropies determined in a companion study and with data from the literature to estimate the ther- modynamic and thermophysical properties of the beryllium minerals. Eighty-six data sets containing over 1000independent observations were evaluatedusing the program eHASE2o. The values of G!rr,, (kJ/mol) and S!rr., (J/(K.mol)) with their uncertainties(2o) arebehoite -827.3(6.7),45.57(0.18);bertrandite -4300.6(1.6), I72.ll(0.77); anhydrousberyl -8500.4(3.8),346.7(4.7);chrysoberyl -2176.2(1.5), 66.25(0.30); euclase -2370.2(r.l), 89.1 l (0.a0);and phenakite- 2028.4(0.9), 63.43(0.27). The effect of water on the stability of beryl is treated as a purely volumetric interaction : - Gr, r ty*ous ueryt Gp, Ii anlyarcu. t" ryl P noiaZu, where Z*" is an effective volume for the fluid occluded by the beryl structure (14.1 cm3/ mol). Not only doesthis simple "bottle model" work as well for beryl as alternative, more sophisticatedmodels, in part owing to the lack of hydration data, it also appearsto work reasonablywell for cordierite. Beryl has a wide stability range consistent with its relative natural abundance. The stability field of beryl is greatly increasedby high fluid pressuresand by alkali-containing solid solutions. The assemblagechrysoberyl + quartz is stableonly at relatively high tem- peratures(>600"C) or with Poro ( P,.o,. At moderate pressureswith decreasingtemper- ature, euclasebecomes stable around 400'C. Euclasereplaces beryl in aluminum silicate- bearing assemblagesin the 300'C range. In the 200"C range, phenakite and bromellite hydrateto bertrandite and behoite,respectively, and pure beryl reactsto euclase+ quartz + bertrandite or phenakite. The predicted phaserelations are in good qualitative agreement 0003-004x/86/0304427 7 $02.00 277 278 BARTON:PHASE EQUILIBRIA IN THE BeO-A1,O,-SiO,-H,OSYSTEM with natural associations.Consideration of the effect of solid solution in beryl improves the agreement. In most geologicenvironments, externally imposed chemical potentials govern the sta- bility of beryllium minerals. As a result, minerals in this system are perhaps most useful as indicators of metasomatic variables. Euclase,for example, has a broad P-f shbility range, but is stable only in environments with unusually high alumina activities, thus accounting for its relative rarity. INrnoouc:ttoN kinds ofsubstitutions: speciesoccupying channel sites and Beryllium, one of the geochemicallyless abundant ele- speciessubstituting for the tetrahedral or octahedral cat- ments, occursas an essentialcomponent in more than 50 ions. The alkaliesoccur in beryl in amounts up to several minerals (Fleischer, 1980). Although rarely composing weight percent, occupying channel sites with chargebal- more than a small portion of any rock, beryllium minerals ancebeing accomplishedby substitution of other cations are fairly common, especiallyin differentiated felsic ig- in the framework sites and accompanied by adjoining neousand related metasomatic rocks. The variety of be- water moleculesin the channels(Hawthorne and eerni, ryllium minerals and their widespread occurrencemean 1977).Lithium, in coupled substitution with the channel that they can be useful petrologic indicators. alkalies,replaced beryllium (Hawthorne and eern!, 1977). Ofthe beryllium minerals,the most common and hence Water, in addition to accompanyingthe alkalies, also oc- the most petrologically and economically important be- cupiesthe channel cavities in a manner similar to that in long to the system BeO-AlrOr-SiOr-HrO (BASH). Over cordierite (Schreyerand Yoder, 1964; Aines and Ross- twenty phasesoccur in this system,and those of geologic man, 1984).Both of these substitutions have a profound interest are listed in Table l. The AlrOr-SiOr-HrO system effect on the stability of beryl. In addition to the alkalies has been intensively studied, and its phase relations are and water, up to several weight percent of magnesium, well understood (seerecent data and reviews by Hemley manganese,iron, and chromium are found in someberyls. et al., 1980; Perkinset al., 19791,thermodynamic com- The iron occupiesboth channel positions and substitutes pilation by Robinson etal.,1982). Thesestudies propose for aluminum in the octahedralsites, whereas chromium, similar phasediagrams for the ASH systemand thus pro- magnesium,and manganesesubstitute for the aluminum vide a reasonablebasis for addition of the component (Goldman et al., 1978;Nassau and Wood, 1968; Wood BeO. and Nassau,1968; Gibbs et al., 1968).Helium, carbon Relatively few thermochemical data are available for dioxide, and argon have also been found in beryl (Beus, beryllium-bearingphases. In this study, phaseequilibrium l 966). and solubility experimentswere performed to provide the Spectroscopicdata on beryl and cordierite suggestthat information neededalong with data from the literature to water occupiestwo distinct positions at low temperatures, derive an internally consistentthermodynamic model for one with the H-H vector normal to c and "sitting" in the phasesin the system.This model, in turn, is used to cal- rings betweenthe large cavities (Type II), the other with culate a petrogeneticgrid for the BASH system and re- the H-H vector parallel to c and located in the large cav- actions in more complex systems. From these calcula- ities (Type I, Wood and Nassau,1968). The abundance tions, deductions can be made about the petrogenesisof of Type II water correlateswell with the alkali content; rocks containing minerals in this system. this correlation leadsto the suggestionthat there is bond- Figure I showsthe phasesconsideredin this study pro- ing betweenthem (Goldman et al., 1978; Hawthorne and jected from water. Of thesephases, only beryl hasa widely Cern!, 1977;Wood and Nassau,1968). Aines and Ross- variable composition. The aluminum silicatescan accept man (1984) have shown that with increasingtemperature small amounts of transition metals, and kaolinite, pyro- thesetwo types of water decreasein quantity with equi- phyllite, and diasporemay contain small amounts ofhalo- librium partitioning favoring a third state that has the gens substituting for hydroxyl, but their compositional spectroscopiccharacteristics ofa gas (not bonded or ori- variations are small. Chrysoberyl can contain substantial ented on an IR time scale). iron, chromium, and manganesesubstituting for alumi- Many crystallographicstructure refinementshave been num, but in most casesthis substitution is small (Vlasov, done on phasesin this system(Ross, 1964; R. M. Hazen 1967,Vol. III). Euclaseand phenakiteare uniformly close et al., unpub.). None suggeststhat there is any disorder to their ideal compositions.Ganguli and Saha(1967) re- among the tetrahedralspecies. The mineralogic properties ported that synthetic bertrandite can contain Be(OH) of the beryllium minerals were recently reviewed by Burt considerablyin excessof the ideal formula, but analyses (1982). of natural bertrandites show no evidence of nonstoi- Thermodynamic data have been measuredfor some of chiometry. the beryllium phasesin this system.Low-temperature heat- Beryl, in contrast to the other phases,exhibits a wide capacity measurementshave been performed on phen- rangeof compositional variation, as a consequenceoftwo akite by Kelley (1939) and on chrysoberyl by Furukawa BARTON: PHASE EQUILIBRIA IN THE BeO-AIO,-SiO,-H,O SYSTEM 279 Table 1. Names, abbreviations,and formulas of some phases of geologicinterest in the BeO-AlrOr-SiOr-HrO system Abbr. Fomula Abbr. Fomul a Diaspore Di Aro(olr) Aluminumsilicate Als At2sio5 Andalusite And Al^si0. Euclase Eu BeAlSi 04(0H) Gibbsite Gb Ar(0H) Behoite Bh Be(0H)z 3 And,Kya,Sil Bertrandite Bt Be4siz07(0H)2 Kaolinite Ka Ar2siZ0s(oH)4 Kyanite Kya AI Beryl Be Be3Al25i 601 8.nH20 25i05 Beryl l'i te Bl Be3si04(0H)2.H20Phenakite Ph 8e,,5i 0, BromelI ite Br Be0 Pyrophyllite Py Ar2si4oto(oH)2 chrysoberyl ch BeAl Quartz Qz si02 "0, Alro, Corundum co At^0. Si I I
Load more

Recommended publications
  • CORDIERITE-GARNET GNEISS and ASSOCIATED MICRO- CLINE-RICH PEGMATITE at STURBRIDGE, I,{ASSA- CHUSETTS and UNION, CONNECTICUTI Fnor B.Cnrbn, [
    THE AMERICAN MINERALOGIST, VOL 47, IVLY AUGUST, 1962 CORDIERITE-GARNET GNEISS AND ASSOCIATED MICRO- CLINE-RICH PEGMATITE AT STURBRIDGE, I,{ASSA- CHUSETTS AND UNION, CONNECTICUTI Fnor B.cnrBn, [/. S. GeologicalSurttey, Washington,D. C. Aesrnacr Gneiss of argillaceous composition at Sturbridge, Massachusetts, and at Union, Connecticut, 10 miles to the south, consists of the assemblagebiotite-cordierite-garnet- magnetite-microcline-quartz-plagioclase-sillimanite. The conclusion is made that this assemblagedoes not violate the phase rule. The cordierite contains 32 mole per cent of Fe- end member, the biotite is aluminous and its ratio MgO: (MgOf I'eO) is 0.54, and the gar- net is alm6e5 pyr26.agro2.espe1.2.Lenses of microcline-quartz pegmatite are intimately as- sociated with the gneissl some are concordant, others cut acrossthe foliation and banding of the gneiss. The pegmatites also contain small amounts of biotite, cordierite, garnet, graphite, plagioclase, and sillimanite; each mineral is similar in optical properties to the corresponding one in the gneiss. It is suggestedthat muscovite was a former constituent of the gneiss at a lower grade of metamorphism, and that it decomposedwith increasing metamorphism, and reacted with quartz to form siliimanite in situ and at lerst part of the microcline of the gneiss and pegmatites These rocks are compared with similar rocks of Fennoscandia and Canada. INtnouucrroN Cordierite-garnet-sillimanitegneisses that contain microcline-quartz pegmatiteare found in Sturbridge,Massachusetts, and Union, Connecti- cut. The locality (Fig. 1) at Sturbridgeis on the south sideof the \{assa- chusettsTurnpike at the overpassof the New Boston Road; this is about 1 mile west of the interchangeof Route 15 with the Turnpike.
    [Show full text]
  • Cordierite-Bearing Gneisses in the West-Central Adirondack Highlands
    Trip A-6 CORDIERITE-BEARING GNEISSES IN THE WEST -CENTRAL ADIRONDACK HIGHLANDS Frank P. Florence Science Division, Jefferson Community College, Watertown, NY, USA 13601 [email protected] Robert S. Darling Department of Geology, SUNY College at Cortland, Cortland, NY, USA 13045 Phillip R. Whitney New York State Geological Survey (ret.), New York State Museum, Albany, NY, USA 12230 Gregory W. Lester Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario, CANADA K7L 3N6 INTRODUCTION Cordierite-bearing gneiss is uncommon in the Adirondack Highlands. To date, it is has been described from three locations, one near the village ofInlet (Seal, 1986; Whitney et aI, 2002) and two along the Moose River further to the west (Darling et aI, 2004). All of these cordierite occurrences are located in the west-central Adirondacks, a region characterized by somewhat lower metamorphic pressures as compared to the rest of the Adirondack Highlands (Florence et aI, 1995; Darling et aI, 2004). In the Fulton Chain of Lakes area of the west-central Adirondack Highlands, a heterogeneous unit of metasedimentary rocks, including cordierite-bearing gneisses, forms the core of a major NE to ENE trending synform. Cordierite appears in an assortment of mineral assemblages, including one containing the uncommon borosilicate, prismatine, the boron-rich end-member ofkornerupine (Grew et ai., 1996). The assemblage cordierite + orthopyroxene is also present, the first recognized occurrence of this mineral pair in the Adirondack Highlands (Darling et aI, 2004). This field trip includes stops at four outcrops containing cordierite in mineral assemblages that are characteristic of granulite facies metamorphism in aluminous rocks.
    [Show full text]
  • Washington State Minerals Checklist
    Division of Geology and Earth Resources MS 47007; Olympia, WA 98504-7007 Washington State 360-902-1450; 360-902-1785 fax E-mail: [email protected] Website: http://www.dnr.wa.gov/geology Minerals Checklist Note: Mineral names in parentheses are the preferred species names. Compiled by Raymond Lasmanis o Acanthite o Arsenopalladinite o Bustamite o Clinohumite o Enstatite o Harmotome o Actinolite o Arsenopyrite o Bytownite o Clinoptilolite o Epidesmine (Stilbite) o Hastingsite o Adularia o Arsenosulvanite (Plagioclase) o Clinozoisite o Epidote o Hausmannite (Orthoclase) o Arsenpolybasite o Cairngorm (Quartz) o Cobaltite o Epistilbite o Hedenbergite o Aegirine o Astrophyllite o Calamine o Cochromite o Epsomite o Hedleyite o Aenigmatite o Atacamite (Hemimorphite) o Coffinite o Erionite o Hematite o Aeschynite o Atokite o Calaverite o Columbite o Erythrite o Hemimorphite o Agardite-Y o Augite o Calciohilairite (Ferrocolumbite) o Euchroite o Hercynite o Agate (Quartz) o Aurostibite o Calcite, see also o Conichalcite o Euxenite o Hessite o Aguilarite o Austinite Manganocalcite o Connellite o Euxenite-Y o Heulandite o Aktashite o Onyx o Copiapite o o Autunite o Fairchildite Hexahydrite o Alabandite o Caledonite o Copper o o Awaruite o Famatinite Hibschite o Albite o Cancrinite o Copper-zinc o o Axinite group o Fayalite Hillebrandite o Algodonite o Carnelian (Quartz) o Coquandite o o Azurite o Feldspar group Hisingerite o Allanite o Cassiterite o Cordierite o o Barite o Ferberite Hongshiite o Allanite-Ce o Catapleiite o Corrensite o o Bastnäsite
    [Show full text]
  • 52. Iron-Rich Cordierite Structurally Close to Indialite by Miyoji SAMBONSUGI Geological Institute, Faculty of Arts And. Science
    190 [Vol. 33, 52. Iron-rich Cordierite Structurally Close to Indialite By Miyoji SAMBONSUGI GeologicalInstitute, Faculty of Arts and. Sciences,Fukushima University (Comm.by S. TsuBOI,M.J.A., April 1.2, 1957) Introduction In the course of his geological investigation of the Abukuma plateau, northeast Japan, the writer's attention was drawn to numerous pegmatites intruding the granitic and gneissic rocks which form the foundation of this district. In 1950 the writer found a peculiar mineral from one of the above-mentioned pegmatites, at Sugama. From its appearance the mineral was first identified as scapolite by the writer (Sambonsugi, 1953), but after further observations it has become clear that the mineral belongs to an iron-rich variety of cordierite, and that it is structurally close to indialite, hexagonal polymorph of cordierite, first found by Miyashiro and Iiyama (1954) from the fused sediment in the Bakaro coalfield, India. Miyashir0 et al. (1955) suspected that a structural gradation may exist between the hexagonal lattice of in- dialite and the orthorhombic lattice of cordierite, viz, that there may be some varieties of cordierite structurally close to indialite, though all then known show marked structural difference from indialite. The mineral found by the writer from the Sugama pegmatite is the first example of cordierite structurally close to indialite. It is the purpose of this paper to describe the mode of occurrence, the optical properties, and the chemical composition of the mineral. Recent- ly, the optical properties and the unit cell dimensions of the mineral were studied by T. Iiyama (1956). X-ray and thermal studies of the mineral were carried out by Miyashiro (1957).
    [Show full text]
  • High-Pressure Crystal Chemistry of Beryl (Beralrsi.Otr) and Euclase
    American Mineralogist, Volume 71, pages 977-984, 1986 High-pressurecrystal chemistry of beryl (BerAlrSi.Otr) and euclase(BeAlSiO4OH) Rosnnr M. HaznN, ANonpw Y. Au, Llnnv W. FrNcnn GeophysicalLaboratory, CarnegieInstitution of Washington, 2801 Upton Street,N.W., Washington, D.C. 20008 Ansrnlcr Compressibilities and high-pressurecrystal structures of beryl and euclasehave beon determined by X-ray methods at severalpressures. Beryl (hexagonal,space group P6/mcc) has nearly isotropic compressibility; linear compressibilitiesperpendicular and parallel to the c axis ateB':1.72 + 0.04 x l0-a kbar-'and B,:2.10 + 0.09 x 10-akbar-'. The correspondingbulk modulus is 1.70 + 0.05 Mbar if the pressurederivative of the bulk modulus K'is assumedto be 4. Euclase(monoclinic, spacegroup P2r/a)has anisotropic compression,with maximum compressibrlity of 2.44 + 0.05 x l0-a kbar-l parallel to the unique monoclinic b axis, and minimum compressibility of 1.50 + 0.03 x 10-a kbar-' approximately parallel to [01]. The intermediate axis of compressionhas a magnitude of 1.96 + 0.05 x lO-akbar-'in the a-c plane.The bulk modulus of euclaseis 1.59 t 0.03 Mbar if K' is assumedto be 4. The bulk moduli ofBe, Al, and Si cation coordination polyhedrain beryl are all consistent with 1.7 Mbar, which is the crystal bulk modulus. Beryl compressionoccurs primarily by shorteningof cation-anion bond distances.In euclase,the 2.3-Mbar polyhedralbulk moduli are significantly greater than the observed 1.6-Mbar crystal modulus. Compression in euclase,particularly along the b crystallographicaxis, results from a combination of poly- hedral compressionand changesin interpolyhedral angles.
    [Show full text]
  • Heat Capacities and Thermodynamic Functions for Beryl, Beralrsiuotr
    American Mineralogist, Volume 7I, pages 557-568, 1986 Heat capacitiesand thermodynamicfunctions for beryl, BerAlrSiuOtr, phenakite, BerSiOn,euclase, BeAlSiOo(OH)' bertranditeo BeoSirOt(OH)r,and chrysoberyl' BeAl2Oa B. S. HnluNcw.q,Y U.S. GeologicalSurvey, Reston, Y irgrnia22092 M. D. B.nnroN Departmentof Earthand SpaceSciences, University of California,Los Angeles,Los Angeles,California 90024 R. A. Ronrn, H. T. HLsnr.roN, Jn. U.S. GeologicalSurvey, Reston, Y irginia22092 Ansrru,cr The heat capacities of beryl, phenakite, euclase,and bertrandite have been measured betweenabout 5 and 800 K by combined quasi-adiabaticcryogenic calorimetry and dif- ferential scanningcalorimetry. The heat capacitiesof chrysoberylhave beenmeasured from 340 to 800 K. The resulting data have been combined with solution and phase-equilibrium experimentaldata and simultaneouslyfit using the program pHAS2oto provide an internally consistent set of thermodynamic properties for several important beryllium phases.The experimentalheat capacitiesand tablesof derived thermodynamic propertiesare presented in this report. The derived thermodynamic properties at I bar and 298.15 K for the stoichiometric beryllium phasesberyl, phenakite, euclase,and bertrandite are entropies of 346.7 + 4.7, 63.37+0.27,89.09+0.40, andl72.l+0.77 J/(mol'K),respectively,andGibbsfree energiesof formation(elements) of -8500.36 + 6.39, -2028.39 + 3.78, -2370.17 + 3.04, and -4300.62 + 5.45 kJlmol, respectively,and, -2176.16 + 3.18kJ/mol for chrysoberyl. The coefficientscr to c, of the heat-capacityfunctions are as follows: valid phase ct c2 c, x 105 c4 c, x 10-6 range beryl 1625.842 -0.425206 12.0318 -20 180.94 6.82544 200-1800K phenakite 428.492 -0.099 582 1.9886 -5 670.47 2.0826 200-1800K euclase 532.920 -0.150729 4.1223 -6726.30 2.1976 200-1800K bertrandite 825.336 -0.099 651 -10 570.31 3.662r7200-1400 K chrysoberyl 362.701 -0.083 527 2.2482 -4033.69 -6.7976 200-1800K whereC!: cr * ctT + crT2 * coT-os* crT-2and Zisinkelvins.
    [Show full text]
  • Pyrophyllite Solid Solutions in the System A|,O,-S|O,-H,O
    American Minerulogist, Volume 59, pages 254-260, 1974 PyrophylliteSolid Solutions in the SystemA|,O,-S|O,-H,O Pnrr,rp E. RoseNnenc D ep art ment ol G eolo gy, 14as hing ton Stat e U nio er sity, P ullman, 14as hington 99 I 6 3 Abstract Pyrophyllite solid solutions have been synthesized in the system Al,O'-SiOr-H,O between 400' and 565'C at 2 kbar from a variety of starting materials using sealed gold tubes and conventional hydrothermal techniques. The duration of experiments was 3-9 weeks. Products were characterized by X-ray measurementsand by infrared spectroscopy. Appreciably larger basal spacings were observed for pyrophyllite synthesized from gels than for natural pyrophyllite; small amounts of quartz were present in these samples. Basal spacings of pyrophyllite synthesized from mixtures of kaolinite and quartz approach but do not equal those of natural pyrophyllite. Rehydroxylation of dehydroxylated pyrophyllite under hydrothermal conditions suggests that enlargement of basal spacings cannot be due to dehydroxylation. Substitution of the type Al"* + H* : Sia* is proposed to explain the observed variations. The coupled substitution of Al3* and (OH)- for Sin*and O- results in expanded basal spacingsdue largely to the formation of OH on the basal surface and in increased thermal stability due to the formation of H-bonds between oxygens in adjacent silica sheets.Analyses of natural pyrophyllite also suggest limited substitution of this type. Failure to recognize these substitutions in synthetic samples accounts, in part, for dis- crepancies in the reported thermal stability of pyrophyllite. Phase characterization, often lack- ing, is essentialin experimentalstudies of mineral stabilities.
    [Show full text]
  • Geochemical Journal, Vol. 55 (No. 4), Pp. 209-222, 2021
    Geochemical Journal, Vol. 55, pp. 209 to 222, 2021 doi:10.2343/geochemj.2.0630 10Be/9Be ratios of phenakite and beryl measured via direct Cs sputtering: Implications for selecting suitable Be carrier minerals for the measurement of low-level 10Be ATSUNORI NAKAMURA,1* ATSUYUKI OHTA,1 HIROYUKI MATSUZAKI2 and TAKASHI OKAI1 1Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan 2Micro Analysis Laboratory, Tandem Accelerator (MALT), The University Museum, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan (Received December 23, 2020; Accepted April 29, 2021) Preparing Be carrier solutions with low 10Be/9Be ratios is essential for the applications of in-situ-produced cosmogenic 10Be in geochronology. This is because commercially available Be carriers are non-negligibly contaminated by 10Be. Recently, in-house Be carriers have been successfully applied to samples that contain small amounts of in-situ-produced 10Be. The first step in preparing in-house Be carriers is selecting suitable Be-bearing minerals that contain less 10Be. Here, we present a simple method for selecting appropriate raw minerals for in-house Be carriers. That is, measuring the 10Be/ 9 10 9 Be ratios of Be-bearing minerals by direct Cs sputtering. Analyses of the Be/ Be ratios of phenakite (Be2SiO4) and beryl (Be3Al2Si6O18) obtained from a mineral collection at the Geological Survey of Japan indicate that phenakite gener- ally contains more 10B, interfering isobar of 10Be, than beryl. In addition to the necessity of finding raw materials that contain low 10Be, our results indicate that it is preferable to select a starting material with a low B concentration.
    [Show full text]
  • Optical Properties of Common Rock-Forming Minerals
    AppendixA __________ Optical Properties of Common Rock-Forming Minerals 325 Optical Properties of Common Rock-Forming Minerals J. B. Lyons, S. A. Morse, and R. E. Stoiber Distinguishing Characteristics Chemical XI. System and Indices Birefringence "Characteristically parallel, but Mineral Composition Best Cleavage Sign,2V and Relief and Color see Fig. 13-3. A. High Positive Relief Zircon ZrSiO. Tet. (+) 111=1.940 High biref. Small euhedral grains show (.055) parallel" extinction; may cause pleochroic haloes if enclosed in other minerals Sphene CaTiSiOs Mon. (110) (+) 30-50 13=1.895 High biref. Wedge-shaped grains; may (Titanite) to 1.935 (0.108-.135) show (110) cleavage or (100) Often or (221) parting; ZI\c=51 0; brownish in very high relief; r>v extreme. color CtJI\) 0) Gamet AsB2(SiO.la where Iso. High Grandite often Very pale pink commonest A = R2+ and B = RS + 1.7-1.9 weakly color; inclusions common. birefracting. Indices vary widely with composition. Crystals often euhedraL Uvarovite green, very rare. Staurolite H2FeAI.Si2O'2 Orth. (010) (+) 2V = 87 13=1.750 Low biref. Pleochroic colorless to golden (approximately) (.012) yellow; one good cleavage; twins cruciform or oblique; metamorphic. Olivine Series Mg2SiO. Orth. (+) 2V=85 13=1.651 High biref. Colorless (Fo) to yellow or pale to to (.035) brown (Fa); high relief. Fe2SiO. Orth. (-) 2V=47 13=1.865 High biref. Shagreen (mottled) surface; (.051) often cracked and altered to %II - serpentine. Poor (010) and (100) cleavages. Extinction par- ~ ~ alleL" l~4~ Tourmaline Na(Mg,Fe,Mn,Li,Alk Hex. (-) 111=1.636 Mod. biref.
    [Show full text]
  • The Pyrophyllite Deposits of North Carolina
    North Carolina Department of Conservation and Development Wade H. Phillips, Director BULLETIN NUMBER 37 THE PYROPHYLLITE DEPOSITS OF NORTH CAROLINA With A MORE DETAILED ACCOUNT OF THE GEOLOGY OF THE DEEP RIVER REGION By JASPER L. STUCKEY, Ph. D. RALEIGH 19 28 MEMBERS OF THE BOARD OF CONSERVATION AND DEVELOPMENT Governor A. W. McLean, Chairman, ex offtcio Raleigh S. Wade Marr __._ Raleigh B. B. Gossett Charlotte Jas. G. K. McClure, Jr Asheville Fred I. Sutton ~ _: .. Kinston E. D. Cranford . Asheboro R. Bruce Btheridge Manteo Santford Martin . ; Winston-Salem E. S. Askew Merry Hill J. Q. Gilket Marion F. S. Worthy Washington George L. Hampton Canton Frank H. Stedman Fayetteville Wade H. Phillips, Director, Raleigh LETTER OF TRANSMITTAL Raleigh, N. C, August 1, 1928. To His Excellency, Hon. A. W. McLean, Governor of North Carolina. Sir:—I herewith submit for publication as Bulletin No. 37 of the publications of the North Carolina Department of Con servation and Development a report on The Pyrophyllite De posits of North Carolina, which has been prepared by Dr. Jasper L. Stuckey, former State Geologist. This is the first complete report on the pyrophyllite deposits of this State and will, therefore, be of great interest to those who desire infor mation on such material. Yours respectfully, Wade H. Phillips, Director, North Carolina Department of Conservation and Development. AUTHOR'S FOREWORD This report was begun as a special investigation of the geology and pyrophyllite deposits of the Deep River Region, and accord ingly a detailed geologic map of that region was prepared. As the work progressed, other pyrophyllite deposits were found outside the area mapped.
    [Show full text]
  • The Seven Crystal Systems
    Learning Series: Basic Rockhound Knowledge The Seven Crystal Systems The seven crystal systems are a method of classifying crystals according to their atomic lattice or structure. The atomic lattice is a three dimensional network of atoms that are arranged in a symmetrical pattern. The shape of the lattice determines not only which crystal system the stone belongs to, but all of its physical properties and appearance. In some crystal healing practices the axial symmetry of a crystal is believed to directly influence its metaphysical properties. For example crystals in the Cubic System are believed to be grounding, because the cube is a symbol of the element Earth. There are seven crystal systems or groups, each of which has a distinct atomic lattice. Here we have outlined the basic atomic structure of the seven systems, along with some common examples of each system. Cubic System Also known as the isometric system. All three axes are of equal length and intersect at right angles. Based on a square inner structure. Crystal shapes include: Cube (diamond, fluorite, pyrite) Octahedron (diamond, fluorite, magnetite) Rhombic dodecahedron (garnet, lapis lazuli rarely crystallises) Icosi-tetrahedron (pyrite, sphalerite) Hexacisochedron (pyrite) Common Cubic Crystals: Diamond Fluorite Garnet Spinel Gold Pyrite Silver Tetragonal System Two axes are of equal length and are in the same plane, the main axis is either longer or shorter, and all three intersect at right angles. Based on a rectangular inner structure. Crystal shapes include: Four-sided prisms and pyramids Trapezohedrons Eight-sided and double pyramids Icosi-tetrahedron (pyrite, sphalerite) Hexacisochedron (pyrite) Common Tetragonal Crystals: Anatase Apophyllite Chalcopyrite Rutile Scapolite Scheelite Wulfenite Zircon Hexagonal System Three out of the four axes are in one plane, of the same length, and intersect each other at angles of 60 degrees.
    [Show full text]
  • THE BIRON HYDROTHERMAL SYNTHETIC EMERALD by Robert E
    THE BIRON HYDROTHERMAL SYNTHETIC EMERALD By Robert E. Kane and Richard T. Liddicoat, ]r. A new synthetic emerald grown in Western merald was first synthesized by Ebelman in 1848 by Australia is now commercially available E adding natural emerald powder to a molten boric acid as faceted stones. Infrared spectra revealed flux, which produced very small prismatic emerald crys- the presence of water, thereby confirming tals as the mixture cooled. In the ensuing years, the flux that these synthetic emeralds are synthe- growth of synthetic emerald was achieved by many re- sized by a hydrothermal process. Chemical searchers (Nassau, 1980; Sinkankas, 198 1). In 1957, the analysis showed that they contain vana- dium as well as lesser amounts of chro- growth of minute beryl crystals by a hydrothermal process mium. This new synthetic exhibits some was first reported [Wyart and ¤6avnic~r1957). Although characteristics that are distinctly different many processes for growing synthetic emerald hydro- from other synthetic emeralds and there- thermally have been described since then (summarized in fore must now be considered when identi- Sinkankas, 1981),until recently only three major produc- fying emeralds. In addition to distinctive tions of hydrothermal synthetic emerald have been com- inclusions such as gold, the Biron synthetic mercially available to the jewelry trade: Linde (patented is inert to ultraviolet radiation, has a spe- process now owned by Regency), Lechleitner (full syn- cific gravity of 2.68 -2.71, and refractive thetic in addition to overgrowth), and, most recently, those indices of = 1,569 and (D = 1.573. This ar- grown in the Soviet Union (see Talzubo, 1979).
    [Show full text]