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American Mineralogist, V o lume 95, pages 1527–1532, 2010

Françoisite-(Ce), a new mineral species from La Creusaz uranium deposit (Valais, Switzerland) and from Radium Ridge (Flinders Ranges, South Australia): Description and genesis

Ni c o l a s Me i s s e r,1,* Jo ë l Br u g g e r,2,3 st e f a N aN s e r M e t ,1 Ph i l i P P e th é l i N ,4 a N d fr a N ç o i s Bussy5

1Musée de Géologie and Laboratoire des Rayons-X, Institut de Minéralogie et de Géochimie,
UNIL, Anthropole, CH-1015 Lausanne-Dorigny, Switzerland
2South Australian Museum, North Terrace, 5000 Adelaide, Australia
3TRaX, School of Earth and Environmental Sciences, University of Adelaide, 5005 Adelaide, Australia
4Laboratoire des Rayons-X, Institut de Minéralogie et de Géochimie, UNIL, Anthropole, CH-1015 Lausanne-Dorigny, Switzerland
5Laboratoire de la microsonde électronique, Institut de Minéralogie et de Géochimie, UNIL, Anthropole, CH-1015 Lausanne-Dorigny, Switzerland

aB s t r a c t

The new mineral françoisite-(Ce), (Ce,Nd,Ca)[(UO2)3O(OH)(PO4)2]·6H2O is the Ce-analog of françoisite-(Nd). It has been discovered simultaneously at the La Creusaz uranium deposit near Les Marécottes in Valais, Switzerland, and at the Number 2 uranium Workings, Radium Ridge near Mt. Painter, Arkaroola area, Northern Flinders Ranges in South Australia. Françoisite-(Ce) is a uranylbearing supergene mineral that results from the alteration under oxidative conditions of REE- and U4+- bearing hypogene minerals: allanite-(Ce), monazite-(Ce), ±uraninite at Les Marécottes; monazite-(Ce), ishikawaite-samarskite, and an unknown primary U-mineral at Radium Ridge. The REE composition of françoisite-(Ce) results from a short aqueous transport of REE leached out of primary minerals [most likely monazite-(Ce) at Radium Ridge and allanite-(Ce) at La Creusaz], with fractionation among REE resulting mainly from aqueous transport, with only limited Ce loss due to oxidation to Ce4+ during transport.
Keywords: Françoisite-(Ce), new mineral, rare earth elements, supergene

  • iN t r o d u c t i o N
  • oc c u r r e N c e s a N d g e o l o g i c a l s e t t i N g s

  • The phosphate françoisite-(Ce), (Ce,Nd,Ca)[(UO2)3O(OH)
  • At both localities (La Creusaz and Radium Ridge), fran-

(PO4)2]·6H2O, is a new mineral species discovered simultane- çoisite-(Ce) forms part of a varied assemblage of uranyl-bearing ously at the La Creusaz uranium deposits near Les Marécottes minerals resulting from the alteration of a primary uranium in Valais, Switzerland, and at the Number 2 uranium Workings, (±REE) mineralization. However, the metallogenesis, geochemiRadium Ridge near Mt. Painter, Arkaroola area, Northern cal, and mineralogical characters of both occurrences are very Flinders Ranges of South Australia. At the La Creusaz deposit, different, as summarized below. françoisite-(Ce) was first found in 1981 but analyzed and identified as a new mineral species only in 1999.

La Creusaz uranium prospect

  • Françoisite-(Ce) is the Ce-analog of françoisite-(Nd), a
  • Françoisite-(Ce) was found in the “Gisiger” surface scratching

mineral described by Piret et al. (1988) from Kamoto, Shaba, (~630 m2) at the La Creusaz uranium prospect near the village Democratic Republic of Congo (RDC). The new mineral is of “Les Marécottes” (canton Valais, Western Alps, Switzerland; named françoisite-(Ce) following rule of Levinson (1966) in Swiss federal coordinates: 566.208/107.809; altitude 1642 m).The accordance with the International Mineralogical Association uranium deposit of La Creusaz was discovered in 1973 (Gilliéron (IMA) recommendations for the nomenclature of rare-earth ele- 1988), and explored episodically between 1973 and 2008 using ment (REE)-bearing minerals. The new mineral was approved drill holes, surface scratching, and galleries.

  • by the IMA Commission on New Minerals and Mineral Names
  • The mineralization occurs in hydrothermal breccia veins at

(vote no. 2004-029). Holotype specimens are deposited at Musée the contact between the pre-Variscan gneissic basement of the géologique cantonal, Lausanne, Switzerland, under the follow- Aiguilles Rouges Massif and the Carboniferous (Variscan) Valing catalog numbers: MGL58321 (La Creusaz, Les Marécottes, lorcine granite.According to Meisser (2003), the complex mineral Valais, Switzerland) and MGL79288 (Number 2 Workings, Ra- assemblages and ore textures found at La Creusaz result from a dium Ridge, Arkaroola, South Australia). Due to the abundance complex geological history. and quality of crystals found at La Creusaz, most analyses were performed on material from this locality.
(1) The primary mineralization event (probably Permo-Triassic) resulted in the precipitation of uraninite and pyrite in breccia and veins. A second, later mineralization stage is characterized by intense brecciation and silicification with precipitation of

  • minor amounts of siderite, chalcopyrite, sphalerite, Se-bearing
  • * E-mail: [email protected]

  • 0003-004X/10/0010–1527$05.00/DOI: 10.2138/am.2010.3413
  • 1527

  • 1528
  • MEISSER ET AL.: FRANçOISITE-(Ce), A NEW MINERAL SPECIES

galena, and laitakarite [Bi4(Se,S)3]. Laitakarite gave a Pb/Pb age al. 2003b; Coats and Blissett 1971). The workings are located in

  • of 239 ± 7 My (Triassic).
  • the Mesoproterozoic Mt. Painter Inlier in the Northern Flinders

(2) The ores were partially remobilized during the Tertiary Ranges, South Australia (Drexel et al. 1993; Fanning et al.
Alpine metamorphism under lowest Greenschist facies conditions. 2003). The Mt. Painter Inlier contains large volumes of granites Locally intense fluid circulation led to the formation of the rare min- and gneisses highly enriched in U and Th (several tens of parts erals wittite [Pb3Bi4(S,Se)9] and Se-rich weibullite [Pb5Bi8(Se,S)18] per million). The radiogenic heat released by these granites is by sulfidation of laitakarite. In late-stageAlpine vugs (~2.5 kbar and responsible for a long-lasting thermal anomaly (e.g., Sandiford 350 °C), well-shaped Dauphiné habit quartz crystals coexist with et al. 1998; Neumann et al. 2000), which resulted in large-scale albite, abundant clinochlore ± chamosite, coffinite, arsenopyrite, hydrothermal activity within and around the Mt. Painter area. chalcopyrite, minor Ag-poor lillianite (AgxPb3–3xBi2+2xS6, with x = Small-scale on-going hydrothermal activity—probably limited 0.12), Se-poor galena, anatase, and titanite.
(3) Strong mechanical and chemical weathering occurred dur- mented by the Paralana Hot Springs (Brugger et al. 2005).

  • ing the Quaternary, especially at the beginning of the interglacial
  • The province contains many small Paleozoic hematite-U-Cu-

by the low precipitation levels since the last ice age—is docu-
Riss-Wurm period. At this time, the melting of the ice sheet Nb-REE deposits, and a large epithermal system characterized by produced rapid decompression, uplift, and fracturing of the rocks, complex quartz±fluorite veins and breccias (Coats and Blissett followed by intense fluid circulation. The oxidation of pyrite and 1971; Drexel and Major 1990; Elburg et al. 2003). The Number arsenopyrite produced acidic fluids, which reacted with uraninite, 2 Workings explored a small (~4 × 4 m) lens of coarse hematitefluorapatite, and silicates from the host rock. This resulted in the quartz ore; the other primary minerals include monazite-(Ce), formation of a complex assemblage of uranyl-bearing minerals xenotime-(Y), a solid solution between ishikawaite and Fe-rich at La Creusaz, characterized by the coexistence of silicates, oxy- samarskite, an unidentified Ca-Fe-phosphate, and an unidentified hydroxides, arsenates, phosphates, and selenites. This event is U(Pb,Mn)-oxide primary mineral always fully replaced by a comdated at ~140000 years using the 238U-234U-230Th disequilibrium plex assemblage of secondary minerals (mainly metaschoepite method applied to the abundant uranophane characteristic of and a Mn-Pb oxide, probably cesarolite). The phosphate-REE this weathering stage. The new mineral species described here, mineralization can constitute >50 vol% of the ore locally. This

  • françoisite-(Ce), crystallized during this stage.
  • Fe-U-Cu-Nb-REE mineralization is overprinted by the epith-

(4) Since the end of the underground exploration in 1981, ermal mineralization, consisting of quartz veins with abundant exposed veins and stockpiled U ore have been subjected to pseudomorphs after fluorite and “needle quartz” growing around acid mine drainage water and atmospheric oxygen in the (now usually dissolved) acicular crystals of laumontite.Asimilar abandoned galleries. Oxidation of the sulfides (mainly pyrite evolution from magmatic hydrothermal conditions (510 ± 20 °C) and chalcopyrite) in the presence of strong bacterial activ- to epithermal (100–140 °C) was described by Bakker and Elburg ity resulted in the production of acid (pH ~ 3.1), sulfate-rich (2006) from unusual diopside-titanite veins located ~3 km SSE waters. These waters reacted with uraninite, clinochlore, illite, of the Number 2 Workings. A distinct geochemical relationship calcite, and siderite to form a rich assemblage of neoformed between the hematite lens at Number 2 and the titanite-diposide uranyl minerals, including the new minerals marécottite veins is indicated by the presence of Nb-rich inclusions in the tiMg3(UO2)8(SO4)4O6(OH)2·28H2O (Brugger et al. 2003a) and tanite, as well as abundant fluorapatite (Bakker and Elburg 2006). pseudojohannite Cu5(UO2)6(SO4)3(OH)16·14H2O (Brugger et The titanite was dated at 440 Ma at the time of intrusion of the al. 2006b), as well as jáchymovite (UO2)(SO4)(OH)14·13H2O, British Empire Granite (Elburg et al. 2003), but paleomagnetic johannite Cu(UO2)2(SO4)2(OH)2·8H2O, magnesiozippeite data suggest that at least two major hydrothermal events affected Mg(UO2)2(SO4)O2·3.5H2O, natrozippeite Na(UO2)2(SO4) the Mt. Painter area in the Permo-Carboniferous (Idnurm and O(OH)·2H2O, rabejacite Ca(UO2)4(SO4)2(OH)6·6H2O, schoe- Heinrich 1993).

  • pite (UO2)8O2(OH)12·12H2O, schröckingerite NaCa3(UO2)
  • At the Number 2 Workings, secondary uranium minerals

(CO3)3(SO4)F·10H2O, uranopilite (UO2)6(SO4)(OH)10·12H2O, occur mainly in the cavities of the epithermal quartz, and in zippeite K(UO2)2(SO4)O(OH)·2H2O, and an unnamedAl-equiv- cavities resulting from the dissolution of the unknown primary

  • alent of coconinoite Al4(UO2)2(PO4)4(SO4)(OH)2·20H2O.
  • U-(Pb,Mn)-oxide mineral. Françoisite-(Ce) was found in the

At La Creusaz, françoisite-(Ce) is directly associated with latter location. Françoisite-(Ce) from Number 2 Workings is abundant uranophane, novácěkite-metanovácěkite, jarosite and directly associated with metatorbernite, barite, an abundant minor françoisite-(Nd), metatorbernite, metazeunerite, arsenura- kaolinite-group mineral, and cesarolite(?). Other secondary nospathite, uranospathite, and hyalite. Primary allanite-(Ce), minerals reported at Number 2 Workings include curite, billietite, monazite-(Ce), and fluorapatite are locally abundant as accessory boltwoodite, hyalite, kasolite, rutherfordine, schoepite, and metminerals in various gneisses that serve as a matrix for specimen aschoepite, soddyite, spriggite, meta-torbernite, uranophane-β,

  • of the new mineral.
  • weeksite, and the new mineral IMA no. 2008-022: monoclinic-

UO2(OH)2 (Brugger et al. 2003b, 2004).

Number 2 Workings, Radium Ridge
Appearance and physical properties

The Number 2 Workings, located on Radium Ridge near Mt.

  • Painter, nearArkaroola, Northern Flinders Ranges, SouthAustra-
  • At the Number 2 Workings, françoisite-(Ce) forms scale-

lia (Australian Grid coordinates: 54J 0339200mE, 6655430mN), shaped crystals up to 1 mm in size; X-ray diffraction reveals are part of several uranium prospects discovered in 1906 and that the crystals are mixed with microscopic inclusions of a exploited episodically for radium from 1906–1934 (Brugger et kaolinite-group mineral. Consequently, physical properties

  • MEISSER ET AL.: FRANçOISITE-(Ce), A NEW MINERAL SPECIES
  • 1529

for françoisite-(Ce) were measured on the more abundant and Crystallography pure material from La Creusaz. At La Creusaz, françoisite-(Ce)
Single-crystal X-ray studies could not be carried out because

of lack of suitable crystals. The powder X-ray diffraction patterns of françoisite-(Ce) from both localities were collected by means of a Gandolfi camera (114.6 mm Gandolfi camera, CuKα), and are similar to the pattern reported for françoisite-(Nd) by Piret et al. (1988). The unit-cell parameters for the françoisite-(Ce) from La Creusaz were refined from the powder data (Table 2), on the basis of françoisite-(Ce) being isostructural with françoisite-(Nd) (Piret et al. 1988). Françoisite-(Ce) is monoclinic, Z = 4, and probably shares space group P21/c with françoisite-(Nd). The unitcell dimensions refined from the powder data in Table 2 are a = 9.295(6), b = 15.53(2), c = 13.718(8) Å, β = 112.39(4)°, with V = forms radial aggregates constituted of lemon yellow prismatic crystals elongated along [001] and measuring up to ~100 µm in length (Fig. 1), growing directly in gneisses adjacent to the uraninite-bearing hydrothermal breccia. Crystals are transparent, with a vitreous luster and a pale yellow (“Naples yellow”) streak (powder). The new mineral shows no fluorescence under UV (short and long wavelengths).
The main observed crystallographic forms are {010} and
{001}. Twinning along the (100) plane is ubiquitous. Françoisite(Ce) is brittle, with uneven fracture, and shows frequent cleavage along (010). Mohs hardness is ~3. Françoisite-(Ce) sinks in Clerici solution (thallium malonate and thallium formate), indicating a density in excess of 4.25 g/cm3, in accordance with calculated density of 4.71 g/cm3. This density was calculated from the empirical formula of the La Creusaz material (Table 1), assuming a water content of six H2O and one hydroxyl group per formula unit, and a cell volume of 1831 Å3 (unit cell refined from powder diffraction data; see below).
Optically, françoisite-(Ce) is biaxial negative. The maximum and minimum values of the refractive indices were measured using the immersion technique (elemental sulfur/diiodomethane solutions). The refractive indices of the liquids were checked using a Leitz-Jelley micro-refractometer with NaD at 24.5 °C. The measured extreme values are nmin = 1.740(1) and nmax = 1.750(1). Pleochroism is weak, X pale yellow,Yyellow. The average refractiveindexcalculatedusingtheGladstone-Dalerelationshipis1.750 for the average composition for the La Creusaz material in Table 1, normalized to an analytical total of 100 wt%. The constants from Mandarino (1976) and Piret and Deliens (1989) (for UO3) were used. The calculated refractive index corresponds to a superior compatibility index (1 – Kp/KC) = 0.0061 (Mandarino 1981).

fi g u r e 1. Scanning electron micrograph (backscattered electron mode) showing the morphology of the françoisite-(Ce) from La Creusaz.

Chemical composition

Chemical analyses of françoisite-(Ce) were carried out by means of an electron microprobe, and the results are summarized in Table 1. The following X-ray lines and analytical standards were used: UMα-uranium metal; CaKα-wollastonite; BaLα- barite; PbMα-crocoite; FeKα-hematite;AlKα-Al2O3; YLα-YPO4;

LaLα-LaPO4; CeLα-CePO4; PrLα-PrPO4; NdLα-NdPO4; SmLα-

SmPO4; DyLα-DyPO4; PKα-YPO4; SiKα-wollastonite. The following additional elements were measured and found to be present

at or below detection limit: Na2O (≤0.07 wt%), MnO (<0.05 wt%), and SrO (<0.05 wt%). The Cameca SX50 microprobe was oper-

ated at 20 kV, 30 nA. Analyses were conducted using a tightly focused beam scanned over a surface of about 20 µm2 to reduce beam damage due to dehydration, and data were corrected using the Cameca PAP routine (Pouchou and Pichior 1991).
Cerium is the dominant REE in all the grains analyzed (Fig.
2). High Si an Al values observed in analysis from Number 2 Workings, SouthAustralia are related to micrometer scale inclusions of kaolinite, consequently, Si and Al were deducted and the analysis presented in Table 1. Minor amounts of Al in both analysis from La Creusaz and Number 2 Workings are consistent with classical substitution Al3+ ↔ REE3+, and in the case of the phosphuranylite group, the Al term is represented by upalite, Al[(UO2)3O(OH)(PO4)2]·7H2O.

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  • Uranium Deposits

    Uranium Deposits

    IAEA-TECDOC-322 SURFICIAL URANIUM DEPOSITS REPORT OF THE WORKING GROUP ON URANIUM GEOLOGY ORGANIZEE TH Y DB INTERNATIONAL ATOMIC ENERGY AGENCY TECHNICAA L DOCUMENT ISSUEE TH Y DB INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1984 SURFICIAL URANIUM DEPOSITS, IAEA, VIENNA, 1984 IAEA-TECDOC-322 Printed by the IAEA in Austria December 1984 FOREWORD greae Th t surg f intereso e exploration i t r uraniunfo m deposits ove lase th rt decad addes eha d significantlo yt r knowledgou f uraniueo m naturgeologe th d f uraniueo yan m deposits. informatioMuce th f ho n developey db government and industry programmes is not widely available, and in many cases has not been systematically co- ordinated, organized and prepared for publication. With the current cut-back in uranium exploration and research, therreaa s i le danger tha t e knowledgmucth f ho e gained willose b l t and, wit anticipatee hth d resurgence of interest in the future, will again have to be developed, with a consequent loss of time, money and attempn efforta n I o gathe.t t mose th r t important informatio typee th f uraniusn o n o m deposits seriea , f so reports are being prepared, each covering a specific type of deposit. These reports are a product of the Agency's Working Grou n Uraniupo m Geology. This group, whic bees hha n active since 1970, gather exchanged san s information on key issues of uranium geology and coordinates investigations on important geological questions. The project Workine th f so g Grou Uraniun po m Geologprojece th d ytan leaders are: Sedimentary Basin Sandstond san Warre— e Typn eFinc Deposith s Uranium Deposit Proterozoin si c Quartz-Pebble Conglomerate - Desmons d Pretorius Vein Type Uranium Deposits — Helmut Fuchs Proterozoic Unconformit Stratd yan a Bound Uranium Deposit Joh— sn Ferguson Surf icial Deposits — Dennis Toens The success of the projects has been heavily dependent on the dedication and efforts of the project leaders and their organizations.
  • Dissolution Studies of Synthetic Soddyite and Uranophane

    Dissolution Studies of Synthetic Soddyite and Uranophane

    SE9800016 TECHNICAL REPORT 37-15 Dissolution studies of synthetic soddyite and uranophane Ignasi Casas1, Isabel Perez1, Elena Torrero1, Jordi Bruno2, Esther Cera2, Lara Duro2 1 Dept. of Chemical Engineering, UPC 2 QuantiSciSL September 1997 SVENSK KARNBRANSLEHANTERING AB SWEDISH NUCLEAR FUEL AND WASTE MANAGEMENT CO P.O.BOX 5864 S-102 40 STOCKHOLM SWEDEN PHONE +46 8 665 28 00 FAX+46 8 661 57 19 DISSOLUTION STUDIES OF SYNTHETIC SODDYITE AND URANOPHANE Ignasi Casas1, Isabel Perez1, Elena Torrero1, Jordi Bruno2, Esther Cera2, Lara Durcf 1 Dept. of Chemical Engineering, UPC 2 QuantiSci SL September 1997 This report concerns a study which was conducted for SKB. The conclusions and viewpoints presented in the report are those of the author(s) and do not necessarily coincide with those of the client. Information on SKB technical reports from 1977-1978 (TR 121), 1979 (TR 79-28), 1980 (TR 80-26), 1981 (TR 81-17), 1982 (TR 82-28), 1983 (TR 83-77), 1984 (TR 85-01), 1985 (TR 85-20), 1986 (TR 86-31), 1987 (TR 87-33), 1988 (TR 88-32), 1989 (TR 89-40), 1990 (TR 90-46), 1991 (TR 91-64), 1992 (TR 92-46), 1993 (TR 93-34), 1994 (TR 94-33), 1995 (TR 95-37) and 1996 (TR 96-25) is available through SKB. £9-08 Dissolution studies of synthetic soddyite and uranophane Ignasi Casas, Isabel Perez, and Elena Torrero. Dept. of Chemical Engineering, UPC. Jordi Bruno, Esther Cera and Lara Duro QuantiSci SL. ABSTRACT The dissolution of synthetically obtained soddyite and uranophane has been studied in solutions of low ionic strength.
  • Review of Uranyl Mineral Solubility Measurements

    Review of Uranyl Mineral Solubility Measurements

    Available online at www.sciencedirect.com J. Chem. Thermodynamics 40 (2008) 335–352 www.elsevier.com/locate/jct Review of uranyl mineral solubility measurements Drew Gorman-Lewis *, Peter C. Burns, Jeremy B. Fein University of Notre Dame, Department of Civil Engineering and Geological Sciences, 156 Fitzpatrick Hall, Notre Dame, IN 46556, United States Received 19 September 2007; received in revised form 10 December 2007; accepted 12 December 2007 Available online 23 December 2007 Abstract The solubility of uranyl minerals controls the transport and distribution of uranium in many oxidizing environments. Uranyl minerals form as secondary phases within uranium deposits, and they also represent important sinks for uranium and other radionuclides in nuclear waste repository settings and at sites of uranium groundwater contamination. Standard state Gibbs free energies of formation can be used to describe the solubility of uranyl minerals; therefore, models of the distribution and mobility of uranium in the environ- ment require accurate determination of the Gibbs free energies of formation for a wide range of relevant uranyl minerals. Despite dec- ades of study, the thermodynamic properties for many environmentally-important uranyl minerals are still not well constrained. In this review, we describe the necessary elements for rigorous solubility experiments that can be used to define Gibbs free energies of formation; we summarize published solubility data, point out difficulties in conducting uranyl mineral solubility experiments, and identify areas of future research necessary to construct an internally-consistent thermodynamic database for uranyl minerals. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Uranium; Uranyl minerals; Solubility; Gibbs free energy; Thermodynamics Contents 1.
  • Mineralogy, Crystallography and Structural Complexity of Natural Uranyl Silicates

    Mineralogy, Crystallography and Structural Complexity of Natural Uranyl Silicates

    minerals Review Mineralogy, Crystallography and Structural Complexity of Natural Uranyl Silicates Jakub Plášil Institute of Physics ASCR, v.v.i., Na Slovance 1999/2, 18221 Prague 8, Czech Republic; [email protected]; Tel.: +420-775-21-27-57 Received: 10 October 2018; Accepted: 19 November 2018; Published: 27 November 2018 Abstract: Naturally occurring uranyl silicates are common constituents of the oxidized parts (i.e., supergene zone) of various types of uranium deposits. Their abundance reflects the widespread distribution of Si4+ in the Earth’s crust and, therefore, in groundwaters. Up to date, 16 uranyl silicate minerals are known. Noteworthy is that the natural uranyl silicates are not extremely diverse regarding their crystal structures; it is a result of possible concentrations (activity) of Si4+ in aqueous solutions derived from dissolution of primary Si minerals or the composition of late hydrothermal fluids. Therefore, in natural systems, we distinguish in fact among two groups of uranyl silicate minerals: uranophane and weeksite-group. They differ in U:Si ratio (uranophane, 1:1; weeksite, 2:5) and they form under different conditions, reflected in distinctive mineral associations. An overview of crystal-chemistry is provided in this paper, along with the new structure data for few members of the uranophane group. Calculations of the structural complexity parameters for natural uranyl silicates are commented about as well as other groups of uranyl minerals; these calculations are also presented from the point of view of the mineral paragenesis and associations. Keywords: uranyl silicate; crystal structure; structural hierarchy; chemical composition; complexity measures; evolution 1. Introduction Uranyl silicates minerals are typical representatives of the oxidized parts of uranium deposits worldwide [1–5], forming during oxidizing weathering of uraninite, ideally UO2, or coffinite, ideally 4+ U(SiO4).
  • The Discovery of New Mineral Species and Type Minerals from Brazil a Descoberta De Novas Espécies Minerais E Minerais Tipo Do Brasil

    The Discovery of New Mineral Species and Type Minerals from Brazil a Descoberta De Novas Espécies Minerais E Minerais Tipo Do Brasil

    DOI: 10.1590/23174889201500010011 INVITED REVIEW The discovery of new mineral species and type minerals from Brazil A descoberta de novas espécies minerais e minerais tipo do Brasil Daniel Atencio1* RESUMO: Os minerais foram vistos apenas como fontes de produtos ABSTRACT: Minerals were seen merely as sources of chemicals: químicos: minério de ferro, minério de cobre, etc. No entanto, não são iron ore, copper ore, etc. However, minerals are not just chemicals apenas associações de elementos químicos, uma vez que apresentam es- associations, since they display crystal structures. These two features truturas cristalinas. Essas duas características em conjunto proporcionam together provide properties that can be technologically useful. Even propriedades que podem ser tecnologicamente úteis. Mesmo que um though a mineral occurs in very small amount, which does not al- mineral ocorra em quantidade muito pequena, o que não permite a sua low its extraction, it can serve as a model for obtaining the synthetic extração, pode servir como um modelo para a obtenção do análogo sin- analogue on an industrial scale. It is necessary that a new-mineral tético em uma escala industrial. É necessário que uma proposta de novo proposal be submitted for approval by the Commission on New Min- mineral seja submetida à aprovação pela Comissão de Novos Minerais, erals, Nomenclature and Classification (CNMNC) of the Interna- Nomenclatura e Classificação (CNMNC) da Associação Mineralógica tional Mineralogical Association (IMA) before publication. Only 65 Internacional (IMA) antes da publicação. Somente 65 espécies minerais valid mineral species were first described from Brazil, that is, the type válidas foram descritas pela primeira vez no Brasil, isto é, minerais-tipo minerals from Brazil.

  • New Data on Minerals

    Russian Academy of Science Fersman Mineralogical Museum Volume 39 New Data on Minerals Founded in 1907 Moscow Ocean Pictures Ltd. 2004 ISBN 5900395626 UDC 549 New Data on Minerals. Moscow.: Ocean Pictures, 2004. volume 39, 172 pages, 92 color images. EditorinChief Margarita I. Novgorodova. Publication of Fersman Mineralogical Museum, Russian Academy of Science. Articles of the volume give a new data on komarovite series minerals, jarandolite, kalsilite from Khibiny massif, pres- ents a description of a new occurrence of nikelalumite, followed by articles on gemnetic mineralogy of lamprophyl- lite barytolamprophyllite series minerals from IujaVritemalignite complex of burbankite group and mineral com- position of raremetaluranium, berrillium with emerald deposits in Kuu granite massif of Central Kazakhstan. Another group of article dwells on crystal chemistry and chemical properties of minerals: stacking disorder of zinc sulfide crystals from Black Smoker chimneys, silver forms in galena from Dalnegorsk, tetragonal Cu21S in recent hydrothermal ores of MidAtlantic Ridge, ontogeny of spiralsplit pyrite crystals from Kursk magnetic Anomaly. Museum collection section of the volume consist of articles devoted to Faberge lapidary and nephrite caved sculp- tures from Fersman Mineralogical Museum. The volume is of interest for mineralogists, geochemists, geologists, and to museum curators, collectors and ama- teurs of minerals. EditorinChief Margarita I .Novgorodova, Doctor in Science, Professor EditorinChief of the volume: Elena A.Borisova, Ph.D Editorial Board Moisei D. Dorfman, Doctor in Science Svetlana N. Nenasheva, Ph.D Marianna B. Chistyakova, Ph.D Elena N. Matvienko, Ph.D Мichael Е. Generalov, Ph.D N.A.Sokolova — Secretary Translators: Dmitrii Belakovskii, Yiulia Belovistkaya, Il'ya Kubancev, Victor Zubarev Photo: Michael B.

  • The Solubility of Uranophane Under Oxidizing Conditions in Caci2 and Sio2(Aq)

    L The Solubility of Uranophane under Oxidizing Conditions in CaClz and Si02(aq) Test Solutions James D. Prikryl’.’ and William M. Murphy’ 1 Center for Nuclear Waste Regulatory Analyses, Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238-5 166 2Department of Geosciences, California State University, Chico, California 95929-0205 Uranophane /Solubility /Synthesis / Oxidizing conditions / Yucca Mountain Summary. Uranophane [Ca(UOz)2Siz07 6H20] is a corrosion product of long-term leaching of spent fuel under oxidizing conditions and is a weathering product of uraninite in uranium ore deposits hosted by siliceous volcanic rocks. The solubility of uranophane may, therefore, play an important role in radionuclide release at the proposed nuclear waste repository at Yucca Mountain, Nevada. In this study, the solubility of uranophane in Ca- and Si-rich test solutions was investigated. Batch solubility experiments were designed to approach uranophane equilibrium in both undersaturated and supersaturated solutions that had initial U concentrations of 10” to lo-’ mol . L-I in matrices of lo-’ mol . L-’ CaCI2 and 10” mol . L-I SiO,(aq). Experimental solutions were reacted with synthetic uranophane (confumed by XRD and chemical analyses) and analyzed at 1-week intervals over 7 weeks. A drop in solution pH and strong Ca precipitation in solutions with higher initial U concentrations characterized initial reaction of uranophane with experimental solutions. After the initial effect, reaction paths were dominated by uranophane dissolution coupled to uranyl mineral precipitation. Calculated reaction quotients (log Qs) for uranophane dissolution were related to solution pH and ranged from 10.89 to 14.62. Based on higher solution pH, test solutions with lower initial U contents ended closer to the solubility limit of uranophane.