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American Mineralogist, Volume 60, pages 559-565, 1975 Carlinite, TlrS, a New Mineral from Nevada Anrsun S. Reorxn U.S. Geological Suruey,Menlopark, Califurnia94025 AND FRANK W. DrcrsoN Department of Geology, Stanford Uniuersity Stanford, California 94305 Abstract Carlinite,TlrS, occursas small subhedralto anhedralgrainswith fine-grainedquartz and hydrocarboncompoundsin carbonaceous limestonesexposedin the east pit of ihe Carlin mine, Nevada.Freshcarliniteis dark gray with a bright metallicluster and a dark gray to black streak' Carlinite rapidly oxidizesin air, causingexposedsurfacesto become dull and darker in color' The crystallographic parametersof carliniteare:rhombohedral,spacegroup R3, a -- 12.12+ 0.01A, c : 18.175+ 0.005A, z = 27, cer volume : 2310.i * o.o Ai. Carlinite displaysperfect(0001)cleavage,an imperfectprismaticcleavage,and hackly fracture.The strongestX-ray diffractionpeaksand relativeintensitiesare:3.010A, Loo1;2.igo A, 33; l-749A, zo;z.ozoA, 28. Powderid carlinitetendsto showextremepreferredorientation because of the perfectbasalcleavage. Vickershardnessis 23.5* 2.0 kg/mmr;Mohs hardness, l;_density, 8.1 + 0.2 g/cms(meas),8.55 g,/cms(calc).In reflected light, carliniteis_..galena white" with a faint bluishcast,weaklybireflectant,and moderatelyanisotropic,with polarization colors that rangefrom brownish-grayto bluish-gray.Reflectances in air are: Rooo,-= 40.5- 42.0;fiurr* = 39.2- 40.6;Rare,: 38.8- 40.1andRoro,-:39.6 - 41.3.Carliniteis essentially pureTlrS;microprobeanalysisyieldedrl : g2.g3and s : 7.Ij, in wt percent.The mostabundanttraceelement,by emissionspectrographic analysis,is As at levelslessthan 100 ppm. The new mineral is namedafter the Carlin gold depositin which it was discovered. Introduction bearing rocks which contain reducing substances, such as hydrocarbons,and which also have a low A new mineral,carlinite,with compositionTlrS, arseniccontent. SubsequentX-ray and microprobe was discovered at the Carlin deposit, northern examinationof heavymineralconcentrates from carEureka County, Nevada, as an outgrowth of in_ bonaceous, high-thallium, low-arsenic, silicified vestigations of thegenesis of epithermalgold deposits limestonefrom the Carlin depositdemonstratedTlrS in Nevada and Utah (Radtkeand Dickson, 1975). to be present. SomeCarlin-typegold depositspreviouslyhad been The Carlin gold deposit is the largest and best reportedto containabnormallylargeamountsof dis_ known of the disseminated,replacement-type gold persedthalliumin unknownforms(Weissberg, 1969; deposits.The mineralTlzSis named..carlinite"after Radtke et al, 1972;Radtke, Dickson, and Rytuba, the depositin whichit wasfound.The mineralname 1974); however, only at the Carlin mine have and designationasa newmineralhavebeenapproved thallium-bearingmineralsbeendescribed.Thesein_ by the Commission of New Minerals and New clude lorandite,TlAsS, (Radtkeet at, 1973),and or_ Mineral Names of the International Mineralogical piment,AsrS3,that contains0.1 to 0.35 wt percent Association. thallium in solid solution (Radtke et at, 1974). Type material is depositedin the SmithsonianInCrystallineTlrS, synthesized during studiesof the stitution (U.S. National Museum), Washington, systemTlrS-AsrS,in the HydrothermalLaboratory D. C., and in the Epithermal Minerals Collection, at StanfordUniversity,haspropertiesconsistentwith Departmentof Geology, Stanford University,Stanits possibleoccurrenceas a mineral in thallium_ ford. California. 559 A, S. RADTKE, AND F. W. DICKSON like carbon compounds apparently moved into the mineralized rocks along permeablezonesduring the Carlinite occurs as small grains randomly scattered hydrothermal episode (Radtke and Dickson, 1975)' through black brecciated fragments of carbonaceous No other hydrothermally deposited sulfide limestonein shearzonesexposedin the eastpit of the minerals were found with carlinite in the samples Carlin gold deposit.The geology of the mine and the samplelocation are shown on the geologicmap of the Cariin deposit by Radtke (1973). The samples that contain carlinite come from the 6440 bench, at an approximate elevation of 6445feet, at mine coordinates 2 3 , 0 5 0N . , 1 9 , 9 0 0E . Gold mineralization at the Carlin deposit affected carlinite. at least the upper 300 meters of siliceous, argillaceous,dolomitic limestonesof the Silurian Roberts Physical and OPtical ProPerties dissolutions Hydrothermal Formation. Mountains Carlinite occurs as small subhedral to anhedral solved calcite and lesser amounts of dolomite, and grains ranging from about 0.005 mm to 0'5 mm in Jiameter. Most grains are irregular and slightly rounded with a few grains showing poorly defined rhombohedral and tabular forms (Fig. l)' The new mineral has perfect(0001)cleavageand an imperfect prismatic cleavage or fracture' Vickers haidness of carlinite, determined with a Leirz hardnessindentor using a 5O-gramload' ranged from these elementsto occur in disseminatedgold deposits 20.1 to 23.8 and averaged23.5kg/mm'(5 determinaof the western United States' tions); the hardness of synthetic TlrS, measured The limestonesof the Roberts Mountains Forma- similarly, ranged from 22.6 to 24.8 and averaged24'5 tion at the Carlin deposit normally contain about 0'3 kg/mm; (5 determinations)'The averagehardnessof wt percent organic carbon, but the rocks which con- both carlinite and synthetic TlzS is about 1 on the tain carlinite have as much as 6 percent organic Mohs hardnessscale.The mineral is soft and deforms carbon (A. S. Radtke, unpublished data)' B' J' easily. This, together with the perfect basal cleavage, Scheiner of the U.S. Bureau of Mines (oral com- introduces difficulties in grinding; we were not able to munication, 1974)reported that organic compounds prevent strong preferred orientation in the powdered in such high carbon material were mostly mixtures of material. The density of carlinite, measured with a hydrocarbons and "humic acid." These petroleum- Berman balance, is 8.1 t 0.2 g cm-3; the calculated densityis 8.55 g cm-'. Ketelaar and Gorter (1939) reporied a density for syntheticTLS of 8'39 g cm-'' Differential thermal analysis of carlinite showed Occurrence I mm Frc. L Carlinite from the Carlin gold deposit (opaque grains), with some quartz (transparent gralns)' Carlinite is dark gray with metallic luster, but fresh surfacesbecome darker gray to black, even dull or earthy, becauseof surfaceoxidation. The streak of fresh carlinite is dark gray to black' In reflected light in air, carlinite is galenawhite with a faint bluish cast' Bireflectanceis generally weak but is slightly stronger along grain boundaries. Carlinite is moderately to distinctly anisotropic with polarization colors vary- CARLINITE T l s t - e l . P h y s i c a l P r o p e r t i e so f s y n t h e t i c T l r S ( Compiled by Trotman- Dickenson, I 973 ) Property Test-s 3. X-ray Powder. Diffraction Data for Carlinite and SyntheticTlrS Carlinite Value Density Melting Point Heat of Fusion ^Y 8.39 e/Dr hkx. 448.50C 3 kcal/no1e (25oc) -23.2 AGfo (25oc) kca!/mo1.e -22.39 Electrlcal Conductivity At melting point Ar 7710c Solubility,20oC In rrater In 0.02 M H2S0q (1.12) kcal/nole 1.75 ohn-]cn-I 33.3 ehr-I"r-l 0.2I5g T12s/1iter 1.4519 T12S/1iter Reflectivity data for carlinite and synthetic TlrS in air are given in Table 2. Crystallography X-ray powder diffraction data for carlinite and To prevent the rapid oxidation and the formation of coatingsof crystallinealterationproductson the surfaces of powderedTlrSgrains,thesamples of both carlinite and synthetic TlrS were ground under acetonein an agatemortar. The suspension wasthen sedimentedon glassplatesunder acetonethat con..Duco.'cetaineda smallamountof acetone-soluble 39,6-4L.3 39.8-41.1 546 38,8-40.1 39,2-40.6 3E.6-40.0 39.3-40.8 I*** 3 ,491 3,497 3.503 3 3.43sJ 3.029.) 3 ,O29t 3,029) 3.43r 3.433 9 3.030 1000 205 214 131 3t2 2.988 2.988 2 . 8 73 2.771 116 223 t25 401 ro7 042 2. 709J 2.709) 2.680 2.596 2.520\ 2.s20) r34 321 027 232 2.386 2.327\ 2.327.) 306 410 315 404 0r8 2.2901 2.290) 2 . 2 72 2.272 2.220 217 226 413 045 324 2.Ll2 2.I42 2.r42 2.I27 2.L27 208 05r 502 009 330 2.084 2,084 2.O45 2.o1eJ 2.Or9) n5 tii It:, 11e 11i ;ii 309 650 dhwA 300 015 o24 006 303 220 t t?i; 470 obselved** 4.543 4 .283 4.I70 3.875 3.635 llt ;rii (nD) I*** dnktA T125 202 113 104 2r1, L22 X-ray powder diffraction data for carlinite were refinedand the unit cell dimensionsweredetermined wavelength observed** 9.087 6 .869 6.058 6.058 5.040 407 Phase calculated* ,9 qhkt^ Synthetic 101 oI2 003 lt0 021 ment. Carlinite Synthetic Tt2S 561 229 336 603 520 40.5-42.O 39.8_4L.1 2 . r , L O 238 3.030 1000 2.712 2,7t0 5 2.520 3 2.323 4 2.290 2.292 25 2,O20 2.Or9 39 L.973 3 I .919 4 2,007 1.e74 r o71l r.937 r.937 1.el6.l I . 9 r6 J I .905 L.874 1. 8 4 5 r.918 r.845 r.827 r . 8 17 ] r.8L7) I . 7e1J r.79LJ L.765 r . tae\ r.74e) 1. 580.) r.6801 1 . 6 8 0| 1.580J 1.6s2.| L.652l 3 1.831 2 1.819 2 l- 792 1.792 t2 L.749 |,749 33 r .681 I .683 L.654 L.652 A. S. RADTKE, AND F. W. DICKSON 562 that synKetelaarand Gorter (1939)established group R3, and with space theticTlzSis rhombohedral the : between agreement 27. Becauseof the close Z those of and carlinite crystallographicparametersof Gorter and Ketelaar synthetic TlrS reported by 1te:e), carliniteis assumedto be isostructuralwith syntheticTLS. The structuremay be regardedas a arrangementof distorted hexagonalclosest-packed interstices octahedral the which in thallium atoms, are ocatoms thallium planes of pairs of between atoms. cupiedby sulfur Tnare3, Continued Synthetlc CarliniEe hkr dtwL 4tw| 0 1.1r 057 0 . 0 .1 2 4t9 606 440 r..632.l r.632J r.51sl 1.515( 1 . 5 1 {4 r.514) 4.0.10 428 35r 3 .0 . 1 2 710 r .4e4) 1 . 4 9 14 r.494) r. 390\ 1.390J 0 . 5. 1 0 348 529 633 4. L . L 2 716 1.3741 L.374) r.2e2I t,292) 1. 263'l r.253) 0.0.15 3.3.I2 449 636 550 I . 2r2l L.2r2l L.2r2l r.2r2l r.2r2) 1 . 6. 1 0 46L 1.2o1l 1 .2 0 U 1.1e3..] r . 1 9 3I 1. l e 3 J 547 642 Obsetved** -I*** observed** Calculated* T125 I*** d,, ^L l3 1.634 r.633 1.513 1.514 r.491 1.490 1 .390 1.388 2 1.372 |.293 3 r.262 2 r ,212 10 1.198 r i374 3 7.261 4 L.2L2 13 1.196 22 13 1.194 3 . 0. 1 5 6.0,12 119 903 820 I .1451 r . r + sI r. r+sI t .t+s) r,146 1.r47 5 . 4. 1 0 r.88 561 1.080.I 1.080J 0.9rs6 1.081 L.079 I7 o.9t57 0.9155 22 1 .3 .1 9 3 , 4, r 7 10.0.10 488 49r o.sosrl o.soez I 0.9088 0.9088 9 0.9053 0.9053 L3 0.8984 0.8985 9 0.8889 0. 8889 I1 I-145t 0 . 9 0 8 7/ 0 . e 0 8 7I 0 . 9 0 8 1) 0.1.20 3 .5 .1 6 1.11.2 4.O.L9 9 . 2 .r 0 0.9054) o . e o s 3) 0.9053J 0. 8987'f 0.8986J 1 0 .3 . 1 0.88e0) 0 . 8 8 9 0| 0.8889J *A11 calculared i hkl,'s are Listed lndexed, fot L. 4kLZl.745 rndlces and d(Calc) A11 observed froo lhe fokZ's ChemicalComPosition Carliniteis TlrS with only low levelsof otherconstituents.Resultsof quantitativechemicalanalysesof three grains done with the electron microprobe, togetherwith the analyticalconditionsused' are emissionspectroshownin Table4. Semiquantitative graphic analysisof a compositesampleof several large hand-pickedgrains of carlinite show that the mineral may contain small amountsof arsenic but at an abundanceof (100 ppm As (Table5). Synthesis Synthetic carlinite can be made by reacting elemental thallium and sulfur in stoichiometric proportions in sealed evacuatedpyrex tubes at rangingfrom 200'C to 400oC(Carstantemperatures jen, 1867).OthershavepreparedTlzSby reactingTI of H, (Ketelaarand Gorter, and S in an atmosphere Tesr-n4. MicroprobeChemicaiAnalysesof Carlinite leas!- flp2ZO.AaAS conPuter of X-ray powder data using the digltal Equare6 analysis piogtan of ApPle@n and E:ans (1973); and a hexagonal cell wiEh = = e A . 18,175 o L2,I2 and Cu radiation; Ni-filteied are: **X-ray aliffractogEtet condltions scanned at 10 standald; CuKa = 1.54178 X; Sioz used as internal per minule. 2g assignof 1000 Eo Pemit ***SEr;nge6E line is a651gned inten6ity of other lines' lntenslties pent;f larger nunbers as the relative weight Grain No. Tl- I 2 J 92.9s 93.14 92.69 92.93 Percent S 7,24 7, 7 9 7, O 7 7.r7 Total 100.19 100.33 99.76 100.09 Ave. by the use of the cell parameter least-squares programof Applemanand Evans(1973).The rhom100.00 7. 2 7 9 2 . 73 T12S : bohedral unit cell dimensionsfor carlinite are a A; and V : 18.175+0.005 A; . 12.12+O.Or (1) Thallir'rn' Mg charactercondltions: 2310.5t0.6 A'. The cell parameterscomparewell Analytical T1-2S kV, synthetic J-8 crystal' A.DP line, istic : J-ine' ADP with the values of a : |2.2OLO.O7A and c Kd characteristLc standard; (2) sulfur, A for syntheticTlzSreportedby Ketelaar c r y s t a l , 1 8 k V , s y n t h e t i c T 1 2 S s t a n d a r d ' 18.17+0.06 and Gorter(1939). CARLINITE 563 developmetallichemispherical singlecrystalsof a lighterdark-graycolor with one setof parallelfaces, creatingthe appearance of rounddomeswith circular steps(Fig. 2). Carlinite precipitatesfrom alkaline solutionsof thallous salts on reactionwith HrS (Reuter and Goebel,1953;Pascal , 196l),but caremust be taken to excludeoxygen.Fine, reactive,oxygen-freeTl2S canbe madeby reactingthalliumethoxidein ethanol solution,with dry HrS (Brauer,1963). Commerciallyavailable"Tl2S" that we have ex_ aminedhasbeenpoorlycrystalline and impure.Some of the impuritiesare capableof developinghigh gas pressures in closedtubesat high temperatures. Cau_ tion shouldbe exercised in usingcommercial material Ftc. 2. Crystalline synthetic TIS produced by slow cooling of melt. Note that some small droplets formed as single crystals for experimental purposes. bounded incompletely by crystal faces. ChemicalBehavior Carlinite has the highest reported solubility in solids in the system Tl-S have not been studied aqueoussolution of any naturallyoccurringheavy systematically.Compounds with various Tl/S ratios metal sulfide, 215 ppm TlrS at 20oC and I bar have been characterized: TlrS, Tl4Ss,TlS, TlSr, and (Kivalo and Kurkela, 1959; Trotman-Dickenson,TlrS, (Hahn and Klinger, 1949;Lee, l97l). Carstan1973).Carlinitereactswith water,as follows:TlrS + jen (1867), who first studied TlrS, prepared an HrO : 2Tl+ + HS- + OH-. Therefore, a solution amorphous solid with the composition Tlrsa that saturatedwith TlrS is basic,with a calculatedpH of decomposed on heating in uacuo to TlrS plus S. about 10.7.The alkalinereactionof TlrS with water Carlinite oxidizes rapidly on exposure to the atresembles the reactionsof NarS or KrS, in keeping mosphere;oxidation on polished surfacestakes place with the tendencyof thallouscompoundsto resemble during microscopicexamination over a matter of 30 alkali metal compounds in chemical behavior minutes. Carlinite grains up to 0.2 mm in diameter, (Songina,1964).TlrS solubilityis higherin acidsolu_ separatedfrom the host rock and kept in a glassvial tions;for example,a solutionO.O2M/l in HrSOocon- at room conditions for 3 months, oxidized comtains1,451ppm Tl,S (Tablel). The reactionwith H+ pletely. is: Tl,S + 2H+: H,S + 2Tl+. The oxidation of TlrS has been studied by several PhaserelationsbetweenTlrS and othercrystalline workers (Fentress and Selwood, 1948; Reuter and Teslt 5 Semiquantitative Emission Spectrographic """ltr", "f Element C".ttrfu Weight percent Fe Ag As Co 0. 001 0. 0001 < 0 .0 1 0. 0002 Cu Ni T1 TI 0. 0003 0. 0001 0.0002 >50, Analysis of several large grains of carlinite. Lsought buE not found: Al, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Cr, Eu, Ga, ce, Hf, In, K, La, L1, MC, Mo, l4n, Na, Nb, p, pb, pd, pt, Re, s", Si, Sn, sr, Ta, Te, Th, U, v, w, y,' !9, Yb, Zn, Zr.l Goebel, 1953).Lee (1971) summarizedthe reactions involved. The reaction with O, at room temperature proceeds stepwise, and various oxides and sulfuroxygen compounds are produced. According to Lee (1971)the reactionsthat are most likely in the oxidation of carlinite under natural conditions are: first, 2 TlrS + 2 02 - TlrSrOB* TlrO; and second,TlrO + Oz - TlzOe. Given sufficient time, under dry conditions the overall reaction would be: 2 TlrS * 3 02 TlrSrOa + Tl2Os. With water present, thallous thiosulfate degrades according to the reaction: Tl2SrOa* HrO- TlrSO4 + HrS. Thallous sulfate, thiosulfate, and oxide are more soluble than Tl2Or; therefore in nature, where oxidation takes place in contact with aqueous solutions, they would tend to be leached,leaving TlrO3.A rare mineral, avicennite, with a composition of 7 TlrOr.FqO, has been reported from Russia (Karpova et al, 1958);it is not 564 A. S. RADTKE, AND F. W. DICKSON poor, Tl-bearing solutions encounteredS-bearing solutions cannot be ruled out. After carlinite was deposited,it could not have beenexposedvery long to the action of flowing water without dissolving' Therefore,the existenceof carliniteat Carlin attests with which carlinite grains were to the effectiveness solutions,or possibly,to the aqueous protectedfrom since formation. lapsed has that short time rapidly oxidizes carlinite earlier, As mentioned and exposedto rocks host the from when removed is completely mineral the rocks host the In air. GeochemicalImPlications as 6 percent as much containing in a matrix enclosed as reducing act which compounds, carbon Thallium commonly accompaniesarsenic, an- organic of TlzS. prevent the oxidation which gold and agents timony, and mercuryin Carlin-typeepithermal deposits(Weissberg,1969; Radtke and Dickson, Acknowledgments 1974).Only at the Carlin depositis thallium known We thank Dr. CharlesM. Taylor, Mr. John Slack,and Miss Jo to occur in discretemineralswith high thallium con- Peterson,of StanfordUniversity,for their valuableaid in some tent (Radtkeet al,1973;Radtkeet al,1974).In other aspectsof this study. The manuscriptwas greatlyimprovedby depositsas well as at Carlin, thallium is in dispersed critical reviewsby ProfessorsGordon E. Brown and Konrad K' forms in carbonaterocks in and closeto gold ores. Krauskopf of Stanford University, and Wayne E' Hall and Survey'The seniorauthor Thallium readilyforms complexsulfideswith other RichardC. Erd of the U.S. Geological wishesto give specialthanks to Mr. Dan Higley of Carlin Gold metalssuchas As, Sb,Ag, Pb, and Cu. Examplesof Mining Companyfor his assistance and helpin obtainingsamples Tl-containing complex sulfide mineral assemblagesfrom inaccessible areasin the eastpit of the mine. are the classicLengenbachdeposit in the Binnatal References district, Switzerland,describedin a specialvolume publishedby the Natural History Museum,Bern,by Aerrtrunr, D. E., ruo H. T. EvnNs,Jn. (1973)Job9214:Indexing refinementof power diffraction data' U.S. Dep. Stalder et al (1966-1968),Nowacki and Bahezre least-squares Tech. Inform. Seru' PB2l6ltE. Commerce, (1963),Nowackiet al (1967)and Graeser(1967),and Bneuen, G. (1963)Handbookof PreparatiueInorganicChemistry. the Jas Roux deposit,France(Johanet al,1974). l, 2nd ed., AcademicPress,New York' For carliniteto form and to persistrequiresan un- CrnstlNlrr, H. (1367) Ueber Thallium und seine Verbindungen.J. Prak. Chem.1U2,65-89' usualsetof conditions:Tl mustbe in solutionin unusually high concentration; other elements with FrNrress. J., eNo P. Swwoop (1948) Thallous sulfoxylate J. Am. Chem.Soc.70,711. absent; isomerism. which Tl readilycombinesmust be essentially Gn,resrn,S. ( 1967)Ein Vorkommenvon Lorandite(TlAsS) in der a mechanismmust exist that preventsdissolution; Schweiz.Contrib. Mineral. Petrol. 16' 45-50. Beitrage and the environmentmust be reducingduring and H,qsN.H., ANDW. KltNcrn (1949)Riintgenographische zu den System Thallium-Schwefel,Thallium-Selenund after deposition. Z. anorg'Chem.260, ll0-119' Thallium-Tellur. areprobablylow Most solutionsof naturalsystems ltto P. Ptcor (1974)La routhi€rite, Z.. J. MnNrteNNs, JourN. in thallium. Becausecarliniteis so solublein aqueous TlHgAsSr, et la laffittite, AgHgAsS3,deux nouvellesespeces solutions,specialmechanismsare requiredto create min6rales.Bult. Soc.fr. Mineral. Cristallogr.97,48-53. supersaturationand to retain carlinite once it has Klnrovl, K. N., E. A. KoNrov,l, E. D' Llnrtx, ,lr:lp V. F. (1958) Avicennite-a new thallium mineral. Dokl' S,arver-rrv formed.Nothing is known of the solubilityof carlinite S.S.S.R.,2' 23-25(in Russian)'Abstr' Nauk Uzbekistan, Akad. in aqueoussolutionsasa functionof temperatureand l!24. 44, Am. Mineral. in: solupressure,and the extent to which deep-seated J. A. A., ,tNo E. W. Gonren (1939)Die Kristallwith carliniteon Krterenn. tions might becomesupersaturated struktur von Thallosulfid(Tlrs). Z. Kristallogr'l0l{' 367475. approaching the surface cannot be evaluated. KrvlLo. P., exo R. Kunreu (1959)Polarographicdetermination of the solubility product of thallium (I) sulfide' SuomenKem' However,someevidencesupportsthe conclusionthat w2,39. the deposit the Carlin at one stagein the formationof A. G. (1971)The Chemistryof Thallium.ElsevierPublishing Lre, (Radtke Dickson, and hydrothermalsolution boiled Co., Amsterdam,336P. 1974).Lossof waterby boilingsolutionsinitiallyun- Nowecrt, W.. lNn D. Besrzrr (1963) Die Bestimmungder dersaturatedwith carlinite would be an effective chemischeZusammensetzungeiner Sulfosalzeaus dem Lengenbach (Binnatal, Kt. Wallis) mit Hilfe der elektronischen mechanism for increasing TlzS concentration to Mikrosonde. Schweiz.Mineral. Petrol. Mitt 43, 407-412. possibility sulfurthat the Alternatively, saturation. known whether avicenniteis primary or whether it formed by oxidation of primary TlrS. Thallium compounds are highly poisonous (Songina, 1964, p. 319); the potential hazard of carlinite is greaterthan with other metallic sulfides becauseof the rapidity with which TlrS oxidizesto relatively highly soluble compoundssuch as TlrO. Grains of carlinite will developpoisonouscoatings on exposureto air, and we caution that they should be handledcarefully,keepingthis hazardin mind. CARLINITE -, 565 G. Bunnl,P. ENcrl, rNo F. Mene,uo(1967)Uber einige -, C. M. Tlvlon, F. W. DrcKsoN,ANDC. HrnopouLos Mineralstufenaus dem Lengenbach(Binnatal).NeuesJahrb. (1974)Thallium-bearing orpiment,Carlingold deposit,Nevada. Mineral. Monatsh., 2-3, 43-48. J. Res.U.S. Geol.Suru.2,341-342. PesceL,P., Eo. (1961)NouueauTrait| de ChimieMinbrale,VI, R. C, Eno, ANDF. W. DrcxsoN(1973)Occurrence Bore-Aluminum-Gallium-Indium-Thalliwn.Masson,paris,p. 964of lorandite,TlAsSr,at the Carlin gold deposit,Nevada.Econ. 966. Geol 69. l2l-124. P6t-nsoN,H. (1907)Sur lessulfures,seleniures et tellururesde thal- Rruren, VoN Brnrnoro, ANDA. Gorsrr-(1953)UberdieOxydal i u m .C . R . A c a d . , S c 1 l . 4 5 ,l l 8 - 1 2 1 . tion desThallium (l)-Sulfids,Chemismusund Kinetik der Ox_ Rrorxr, A. S. (1973)Preliminary geologic map of the Carlingold ydation bei Zimmertemperatur. Z. Anorg. Altgem.Chem.271, mine, Eureka County, Nevada. U.S. Geol. Sunt Misc. Field 4t 321-337. StudiesMap, MF-537, scalel:4,800. Sor.rcrNrr, O. A. (1964)RedkieMetally (RareMetals).Izdatel'stuo -, ANDF. W. DrcxsoN (1974)Controlson the verticalposi_ Metallurgiya,Moskva (in Russian);Englishtranslationby J. tion of fine-grainedreplacement-type gold deposits.Abstr. of Schmorak, 1970, Israel Program for ScientificTranslations, Papers, Int. Assoc. Genesis Ore Deposits (IAGOD ), 4th Ltd., Jerusalem. Symposium-Varna1974,p. 68-69. Srlloen, H. A., J. IrvrHor, E. NlccLr, S. Gnlrsen, J. AnNorH, -, AND(1975)Genesisand vertical position of fineANDW. Nowecrr (1966-1968)Die Mineralfundstelle Lengengraineddisseminated replacement-type gold depositsin Nevada bach im Binnatal. Separatdruck atrs Jahrbuch des and Utah. Proc. 4th Symp Int. Assoc. Ore Genesis,yarna, NaturhistorischesMweums der Stadt, Bern, Swirzerland,g4 Bulgaria(in press). (Compilation). , ANDJ. Ryruse (1974)Genesisof disseminated TnorurN-DrcrENsoN,A. F., Eo. (1973)Comprehensiue Inorganic gold depositsof theCarlintype.Geol.Soc.Am.70thAnnu.Meet., Chemistry,2, PergamonPress,Oxford, England. CordilleranSection,Las Vegas,Neuada,6,2319-240. Wnrsslenc, B. G. (1969) Gold-silver precipitatesfrom New -, G. HenorouLos, B. P. Fessr,B. J. ScHETNER, ANDM. Es_ Zealandthermal waters.Econ. Geol.il.95-10g. sINcroN(1972)Dataon major and minor elements in hostrocks and ores,Carlin gold deposits,Nevada.Econ.Geol.61,9j 5-979. -, ANDB. J. ScsrrNrn(1970)Studiesof hydrothermal gold deposition(I). Carlin gold deposit,Nevada:The role of carManuscript receiued, January 17, 1975; accepted bonacecusmaterialsin gold deposition.Econ.Geol.65, g7-102. for publication, March 5, 1975.