A meri can M ineralogist, Volume6 3, pages 9 3 8-940, I 978

Kraisslite,a newplaty arsenosilicatefrom SterlingHill, NewJersey

Peur B. Moonn eNo JuN Iror Departmentof the GeophysicqlSciences The Uniuersityof Chicago Chicago,I I linois 606 3 7

Abstract

Kraissliteis a new speciesfrom theSterling Hill Mine, Ogdensburg,Sussex County, New Jersey.It closelyresembles mcgovernite in physicalappearance. The mineraloccurs between the 700' and 950' levelsin the central zincitezone, as films and lensesup to one inch thick along fractures.Twenty specieswere identified in the suite,of which sixteenare secondary minerals., synadelphite, retzian, hodgkinsonite, holdenite, and austiniteconstitute new finds. Kraissliteis hexagonal,a : 8.22(l) c : 43.88(5)4, P6s22,and is probably structurallyrelated to hematoliteand mcgovernite.Specific gravity 3.876, hardness between 3 and4, {0001} perfect and inelastic, color deep coppery-brown, golden-brown, lustersubmetallic, uniaxial (+), birefringenceweak,

Occurrenceand paragenesis thierite,and arsenopyritein the drift, about five feet The new specieskraisslite is known only from the eastof the l0l0 Stopehanging-wall contact. SterlingHill Mine,Ogdensburg, Sussex County, New The orewas high-grade and consisted of , Jersey.We are indebtedto Mr. John Kolic, who franklinite,and zincite,with little or no .The mined the areawhere specimens occurred and pro- willemiteis fleshpink in color, and the grain sizeof vided the bulk of the informationon its occurrence. the ore mineralsis about l-4 mm. A visit by the All samplescame from the l0l0 Stope,which is lo- seniorauthor to the 700' levelshowed the narrow, cated in the narrow portion of the centralzincite thin faultsand thin coatingsof kraisslite.It wasap- zone.Between the 950'and 700' levels, kraisslite was parent that the occurrenceof the arsenateminerals encounteredin a variety of associations,usually was very sporadicand comprisedbut a tiny fraction alongthe surfaceof fracturesin the ore. It occurred of the veinand minerals, the greater portion as films or lensesup to oneinch thick alongfractures beingcarbonates. mostly from the centralportion of the ore to the About thirty specimenswere examinedin more footwall. The ore was cut by a seriesof faults, sepa- detailand identificationwas made by X-ray powder, rated from each other by three to four feet, whose single-crystal,and reflectiongoniometric techniques. strike was north-southand dip approximately45' Of the listin TableI, eveite,synadelphite, and retzian west.The walls of the faults are slickensided.and werehitherto known only aslate-stage fissure miner- their maximum displacementwas about three feet. als from the manganesemines in centralSweden; Associatedminerals include pyrochroite, barite, austinitefrom oxidizedzinc-ore deposits; holdenite, sphalerite,, and minor amountsof a previouslyknown only asa singlespecimen from the host of arsenateminerals (Table l). Mr. Kolic in- nearby Franklin Mine. Hodgkinsonite,sarkinite, forms us that a crosscutbetween the eastand west synadelphite,tetzian, eveite, and allactiteoccur as veins encounteredarsenic, realgar, stibnite, ber- singlecrystals to 0.5mm in greatestdimension, mor- phologicallyclosely resembling earlier goniometric drawingsof thesespecies. One specimen in the Gerst- 1Died June6, 1978. mann collectionshows dark-red hexasonal kraisslite 0003404x / 78 /09 l 0-0938$02.00 938 MOORE AND ITO: KRAISSLITE 939 platesup to I mm, .but no goniometricresults of Table 1. Ores,gangue, and secondaryminerals with kraisslite pyramidaland prismaticfaces could be obtained,as the surfaceevinced some later dissolutionand etch- 0res (synnetmorphic) ing. (zn,lh) (Fe,Itl) The sourceof the As-bearingminerals is a puzzle. Franklinite 20{ wil I enite Zn2siob They all postdatethe oresand gangue,but it is not Zincite ZIrO clearif they are productsof oxidation of pre-existing arsenidesand sulfarsenidesor if they crystallized Gangue from late-stagesolutions from an entirely different Calcite CaCO3 source.The presenceof arsenic-bearingminerals and Secondary Minerals (post -netanorphic) of the boratesussexite may haveoriginated from the Sphalerite ZnS reworkingof an evaporitedeposit, but the evidenceis Pyrochroite Ifrr(OH) 2 not clear.The duplicationof unusuallate-stage spe- Rhodochrosite IttCOs ciesbetween the SterlingHill and Franklindeposits Barite BaSO+ and the centralSwedish ore depositsis Hodgkinsonite Ithznz (OH) z [SiOq ] remarkable,the only substantialdifference being the Sussexite Ith2(oH)[B20q(0H)] presenceof major zincin the New Jerseydeposits. Of l"lagnussonite Mn3*[Ast*Mnr*ot 8ct] the list in Tablel. the elevenminerals which contain Synadelphite (l'tr,Mg) g (OH)g (AsOg) (AsOq)z no zinc are known from both typesof deposits,the Holdenite (l\tr,Mg) 6Zn3(OH) a (AsOr) z (SiO+) six arsenite-arsenateminerals occurrins exclusivelv Kraissl ite (lrh,Mg) 2{Znq (0H) r z (Aso+) q (Sioq) e in thesedeposits. Chlorophoenicite (lrtr,Mg) 3znz (0H) s [ (Aso . sHo. s) (o,oH) g] z Aust inite CaZn(0H) (AsOr) X-ray study Sarkinite lrtr2 (0H) (Aso{) Kraisslite,originally suspected to be mcgovernite, Eveite l.tr2 (o}t) (As0+) Mnz(0H) (As0q) is easilydistinguished from that mineralonly by X- Al lact ite e z Retzian MrzY(0H) (AsOq) ray diffraction.Optical, physical, and chemicalprop- + ertiesso overlapthat othertests are ambiguous. Ow- CuKa radiationand graphitemonochromator, are ing to perfectbasal cleavage, samples of kraissliteand givenin Table2, and the (000/)reflections were used mcgoverniteground in acetoneand allowedto settle to refine the c axis. Relativeintensities on the dif- on glassslides afford mainly (000/)reflections, thus fractogramswere matched with single-crystalphoto- admittinga goodrefinement of thec axis.Randomly- graphsof the 000/row line. orientedmounts of powdersyield very complex pow- der patternsand the consequentdifficulty of distin- Chemicalcomposition guishinga singlephase from a mixture.Although no A specimenshowing abundant kraisslite afforded mcgovernitewas found in situin thisstudy, investiga- flakesoptically free from anyother mineral. An anal- tion on that mineralwas done on an old specimen ysisof mcgovernitewas also made.SiOz was deter- from the 800' leveland approximately700' north in minedgravimetrically; AlrOs, MgO, FeO, and ZnO the westvein, proven to beidentical with the original by atomicabsorption analysis, and HrO(*) by Pen- materialstudied by Palacheand Bauer(1927). field tube.Care was takento distinguishAszOs and Rotation, Weissenberg,and precessionphoto- AsrOuby KMnOotitration and atomic absorption for graphs about [0001],[il-20] and [2]-30]show ex- total arsenic.The resultsare presentedin Table 3. tinctionsonly for 000/,/ I 2n, Laue class6/m2/m2/ Kraisslite,although allied to mcgovernite,contains m, andthe spacegroup is thereforeP6s22. The cellis but littleAs2O3, less MgO, and considerablyless HrO 8.22(l) c : 43.88(5)4,distinct from c : than mcgovernite. 203.15(10)Afor mcgovernite.Significant streaks par- In the absenceof detailedknowledge of the kraiss- allel to the c* axis suggestthat stackingmistakes lite crystalstructure, an unambiguousflormula is dif- occurin the structure,which is not surprisingwhen ficult to propose.The computedcations based on the layeredhematolite structure to whichkraisslite is >(Si + As) : 12lead to 54.10cations in the formula relatedis considered.Structural relations between unit. We propose (Mno2.+rrMgo.oeF e|los)ztZnr(AsOr)r theseand relatedphases were discussedearlier in (SiO4)r(OH),,which to a densityof 3.903g cm-s Mooreand Araki (1978). which is in good agreementwith the specificgravity Resultsof the powderdiffractometer traces, using of 3.876(Berman torsion balance. T : 23.3"C,13.653 940 MOORE AND ITO: KRAISSLITE

Table 2. Kraissliteand mcgovernite.Powder diffractometric resultsr

Kraisslite McGovernite

IlTo do hk.e, c (l) l/Io de cti) r/ro do hk!, c(fr) s r0.9021, 00.4 43.6L 30 l1.205 00.18 20I.69 50 2.604 00.78 203.11 I 7.266 00.6 43.60 70 5.630 00.36 202.68 10 2.560 ? 43 4.385 00.l0 43.85 20 4.832 00.42 202.94 80 2.4t8 00.84 203.t| 35 3.651 00.12 43.81 40 4.228 00.48 202.94 100 2.257 00.90 203.L3 20 3.130 00.14 43.82 20 3.760 00.54 203.04 4 2.LtS 00.96 203.04 2 2.993 ? ----- 10 3.419 ? 4 1.9918 00.102 203.t6 100 2.740 00.16 43.84 20 3.227 ? 4 1.9533 ? 55 2.437 00.18 43.87 6 3.116 ? 6 1.8808 00.108 203.L3 55 2.L94 00.20 43.88 6 3.074 00.66 ;;;-.;; t4 1.6943 00.120 203.32 I 1.4601 00.30 43.80 10 2.900 ? 4 r.62L6 ? 2 L.2907 00.34 43.88 l0 2.852 ? 4 1.6L22 00.t26 203.L4 7 r.2t90 00.36 43.88 30 2.819 00.72 4 1.5461 ? ------2 \.LSS2 00.38 43.90 6 2.76t ? ?2?_?! 2 t,4721 00.138 203.15

?Reflections other than 000.9.

flhe samples were not corrected for absorntion and the c-axes reported in this study were obtained by extrapoiation of ![cos20/si19 + (cos2O/ej] to zero.

mg pureplates). Analysis of the kraisslitestructure is Name presently progress. in It is a pleasureto namethe newmineral in honorof Physicalproperties Mr. Frederickand Mrs.Alice Kraissl of Hackensack. play pivotal Kraissliteoccurs as thin curvedcompact foliated New Jersey,who a rolein themineralogy scalesof palered-brown color to coarse(up to I cm) of Franklinand Ogdensburg.They have been deeply platesof deep coppery-browncolor, much resem- involvedin the Franklin-OgdensburgMineralogical bling mcgovernite,hematolite, and dixenite.The Societyand have contributedsubstantially to the streakis golden-brown,luster submetallic, hardness MineralogicalMuseum in Franklin.The newmineral and namereceived prior approvalby theCommission between 3 and 4, cleavage{0001} perfect to mi- caceous.Thin platesare brittleand inelastic. on New Mineralsand New Mineral Names.Inter- The mineral is copperyin reflectedlight and rich nationalMineralogical Association. brown in transmittedlight. It is uniaxial(+), bi- The typesamples are deposited in the Smithsonian refringenceweak, @ : 1.805(2).The meanindex of lnstitution, National Museum of Natural History refraction,calculated from the relationof Gladstone (NMN H 137017and 137018).The mineral is not rare andDale and usingthe chemical analysis and specific but usuallyoccurs as thin films. gravity, (n) : is 1.759. Acknowledgments Table3. Kraisslite.Chemical analysis and its interpretation We appreciatedthe opportunityto visit the SterlingHill Mine, grantedby the New JerseyZinc Company.Discussions with Dr. R. W. Metsgerand Mr. John Kolic are grateftillyacknowledged. As2Os L7.72 lS.22e6 4.82 4.00 13.15* 12.4a% Mr. RobertA. Svecsguided us undergroundand providedspeci- SiOz 13.8 15.93 7.L8 8.00 8.83 8,92 We As2O3 0,87 0.28 4,78 4,45 mensfor study. alsoappreciate a suiteof secondaryminerals AlzOo O.2l O.l2 nil provided by Mr. Ewald Gerstmannand Mr. John Kolic which MgO 2.5s 2.s6 r.97 I 1I .02 Ll ,27 I'ho 51 .6 50.22 22,80 > 25.6L 24,OO 42.5 42.7s affordedthe newfinds in Table l. Mr. PeteJ. Dunn of the Depart- Fad 1 o, l.7r o.el I 1.49 1,53 ment of Mineral Sciences,Smithsonian Institution informed us of ZnO 8.47 10.78 3.26 4.00 10.58 L0.22 HzO- 3.68 1

lKraisslite (type). Sterling HilI. Ju lto, analyst. Tte specific gravity is 3.876. About 300 ng was ualyzed. References 2conputed weight percent - for (l,tn,e gMg. o aFe. e 3) 2 a Znq (SiOa) e (AsOr) r (1978)Hematolite: (0tl)rz. P = 3.903g cn-', Moore, P. B. and T. Araki a complexdense- packedsheet structure. Am. Mineral.,6J, 150-159. 3conputed cations based on t(Si+As) = 12. Palache,C. and L. H. Bauer(1927) Mcgovernite, a new mineral 4cations for ideal end-n@ber fomla ltr2aZnq(SiOq) o (AsO4) I (OH)I 2. from SterlingHill, N. I. Am. Mineral.,12,373-374. sMccovemite. Ju Ito, amlyst. Manuscript receiued,March 24, 1978;accepted 6Mccovemite. L. H. Bauer analysis in Palache and Baue! (1927). for publication,May 15,1978.