American Mineralogist, Volume 70, pages 379-387, 1985

Ma_nganesehumites and leucophoenicitesfrom Franklin and Sterling- Hill' NewJersev: 'i"? andimplications ;ifi':il1,;;lfiil11"r's'

Perr J. Dullx Department of Sciences Smithsonian lnstitution, Washington, D. C. 20560

Abstract The manganesehumites, (, manganhumite, and ),together with some Mn-bearing samplesof the Mg-humites,and the related phasesleucophoenicite and jerry- gibbsite,from the orebodiesat Franklin and SterlingHill, New Jersey,are describedtogether with analytical data. Solid solution betweenhumite and manganhumiteis at least partially continuous. Expected Mn/Mg solid solutions between alleghanyiteand , and betweensonolite and , are discontinuous; they are interrupted by apparently orderedphases. In all cases,the possibleorderings involve Zn as well as Mn and Mg. There are no Mn end-membersof the manganesehumites at this locality. Manganeseis apparently restricted in (5.42-6.63 Mn per 7 octahedral cations) and in (7.79-8.02Mn per 9 octahedralcations). is common to both leucophoeniciteand jerrygibbsite,but among the Mn-humites,only sonoliteaccepts appreciable Ca (0.65Ca per 9 octahedralcations). There is a "threshold" level ofzinc in all studiedsamples; this "threshold" levelis a constantfor leucophoenicite1-9.3 Znper 3 Si)and alleghanyite(-O.2Zn per 2 Si). No samplesof leucophoeniciteor jerrygibbsite were found to be Zn-ftee,suggesting either that Zn is required for their stability, or that these two phasesmight not be stable as end-members.Fluorine is present in all the Mn-humites and is proportional to the Mg- content,but is absentin leucophoeniciteand jerrygibbsite.

Introduction speciesoccur there; the Mg-humites occur in the The magnesiumhumite species(, chondrodite, host Franklin Marble for the most part, and the Mn- humite, and clinohumite) have been well-studiedand re- humites in the orebodiesthemselves. Franklin is also host cently summarizedby Ribbe (1982).Their manganeseana- to the two anomalous,yet related,species, jerrygibbsite and logues,however, have receivedless attention until recentlv. leucophoenicite,the latter occurringin relative abundance. They are, in general, less common, found in metamor- Second,Mn/Mg solid solution is common in the silicatesat phosed Mn-deposits, and may have lower p-T stability these deposits,and the activity of Fe is limited; in most rangesbecause of expansionof the structure by large Mn cases-it- has been preferentially absorbed by andradite, cations (Ribbe, 19g2j. Winter et al. (19g3) have rJcently which.also may serveto isolate silicate reactionsfrom the shownthat the Mn-humitesfrom Bald Knob. North carol_ ubiquitous . Third, the Mn-humite are ina, require water-rich conditions in silica undersaturate4 moderately common at these deposits, occurring both rocks and that the formation of particular speciescan be within the primary ore and in secondaryvein assemblages. dependent upon complex phase relations involving Last, the Franklin and Sterling Hill assemblagesoffer a XIjI.2OI(XIH2O+ XCOri anA alSlOr;. In addition to thl y1q.". opportunity to study the behavior of in the Mn isotypei of the humites, two other species, leu- Mn-humites, an area of investigationnot previously pur- cophoenicite and jerrygibbsite (Dunn et ut., tggi) a.e suedand which, as is shown below,is worthy of continued known, but the factors which govern their formation investigation, particularly from a structural standpoint. remain obscure. structureshave been determined The speciesdiscussed here are listed in Table 1, together for alleghanyite, magnesian alleghanyite, magnesian with related phases.The Mg-humites from the Franklin manganhumite,and sonolite,as cited below,but the deeree Marble, having already beenstudied by numerousinvesti- of solid solution betweenthe Mg- and Mn-humites is-in- gators, have beenexcluded from this study. Only samples completelydeflned, although Winter et al. (1983)provided with relationsto the ore mineralsare included. a partial plot of Mn/Mg miscibility, and Fukuoka (1981) Chemical composition provided compositionaldata for Japanesesamples. Franklin and SterlingHill provide an ideal "laboratory" The samples studied herein were chemically analyzed in which to investigatethese solid solution relations for a using an ARL-sEMeelectron microprobe utilizing an oper- number of reasons.First, all the known Mg- and Mn- ating voltage of 15 kV and a samplecurrent of 0.025pA, 0003-{04xl85/03O1-{379$02.00 379 3E0 DUNNI HUMITES AND LEUCOPHOENICITES

Table l. The humite and leucophoenicitegroups overgrowthson the underlying alleghanyite,and as appar- ently randomly oriented euhedra,perhaps of a subsequent has beenfound on a l,r2*,si Humite grorJp fh-humitegroup Leucophoenicite growth period. Although alleghanyite few Franklin specimensfrom other assemblages(e.g., r.uNtt

3:l norbergj te unknownin nature unknown C6S84),most of the preservedpink-colored material from However,it is not clear wheth- 5i2 chondrodi te al 1eghanyi te unknown Franklin is leucophoenicite. er this is due to selectiveretention of the more attractive 7t3 humite mnganhumite I eucophoenici te bright pink leucophoeniciteby miners' casualcollecting or 9t4 cl inohumite sonol i te jerryg i bbsi te if this apparentpredominance of leucophoeniciteis due to geochemicalconditions, a viewpoint hereadopted. At Sterling Hill, alleghanyiteoccurs as euhedralcrystals measured on brass. The standards used were synthetic and thin seamswhich crosscutthe ore. Thesecrystals fre- (Mn,Si), synthetic ZnO (Zn), hornblende(MgFe), quently accompanyarsenate species in hydrothermal vein- and fluorapatite(F) for Mn-rich samples.Forsterite (Si,Mg) lets and formed in apparentequilibrium with rare species and rhodonite (Mn,Zn) were employed for Mg-dominant such as kolicite, holdenite,magnussonite, adelite, kraisslite, samples.The samplesare homogeneousat the microprobe Aside from theseuncommon level. The resultant analysesare presentedin Tables 2-6. chlorophoenicite,and others. with alleghanyite are All sampleswere individually verifiedby X-ray powder dif- arsenates,other speciesassociated and carbonates,all of second- fraction techniquesprior to analysis. franklinite, ,barite, ary recrystallization.The observedspecies are all formed Alleghanyite on willemitefranklinite ore which contains abundant cal- cite. The best sampleshave beenfound in recentyears. The Introduction ubiquitous twinning observedby Winter et al.' (1983)in Alleghanyite was first describedfrom the Bald Knob end-memberalleghanyite from Bald Knob was not ob- manganeseprospect, Alleghany County, North Carolina, servedeither in these magnesiancrystals, or in the more by Ross and Kerr (1932)who noted that it was an anhy- Mn-rich material from both Franklin and SterlingHill. drous manganesesilicate related to tephroite.A subsequent study of Bald Knob materialby Rogers(1935) found the Chemical composition mineral to contain HrO, redefined the species as Microprobe analysesof alleghanltes are presentedin Mnr(SiOn)r(OH)r, and noted the apparent relationship to Table 2. Examination of the data revealsseveral features. chondrodite. This isostructural relationship was further First is the absenceof material with end-membercompo- supportedby Campbell Smith et al. (1944)in their descrip- sition. Although near end-membermaterial is known from tion of alleghanyitefrom Rhiw, Wales. The crystal struc- Bald Knob (Simmonset al., 1981;$y'inter et al., 1983),it is ture of alleghanyitewas determinedby Rentzeperis(1970) unknown at Franklin and SterlingHill; most material from usingBald Knob material. there is highly magnesian.Second, samples from Franklin Alleghanyite,ideally Mnr(SiO4)2(OH)2,was flrst noted are markedly lower in Mg than those from Sterling Hill, from Franklin and Sterling Hill by Cook (1969) who reflectingthe higher generalconc€ntration of Mg in Ster- clearedup part of the confusionarising from earlier mor- ling Hill silicates.Third, consideringthe first 6 analyses, phological studies.White and Hyde (1982)examined sev- there appearsto be partial solid solution betweenthe most eral Franklin samplesusing TEM techniques.Although Mn-rich material and that with an Mn: Mg ratio of 4: I they found several phases associatedwith alleghanyite (the next flve analysesin the table),but there is an evident (chiefly leucophoeniciteand sonolite),these minerals were break in solid solution betweenmaterial with MnoMgt and presentas fragments,and not as intergrowths.Recently, a the rest of the samples.The possibleordering of somesam- high-Mg alleghanyitefrom Sterling Hill was describedby ples with a Mn:(Mg,Zn) ratio of 4:1 (8:2) might be per- Petersenet al. (1984),and a refinementof missableinasmuch as alleghanyitehas spacegtoup PLtlb, Sterling Hill material of similar composition by Francis which has equipoint ranks of 4 and 2. Such material,how- (1985a)showed a high degreeofcation ordering.Extensive ever,has not yet beenrefined by crystalstructure analysis' analytical studies(present study) indicate that such order- The next 12 analysesin Table 2 representthe compo- ing may be very commonin samplesfrom SterlingHill. sitions of magnesianalleghanyite from varied sec- ondary fissuresat Sterling Hill. In one samplewhich con- Description tained both massivematerial as a vein-filling,and euhedral Alleghanyiteoccurs at both Franklin and Sterling Hill. crystals (NMNH 134638),the euhedral crystals have a At Franklin, there are few known assemblages.The best- higher Mg content. The ratios of Mn: (Mg,Zn,Fe) vary preservedof thesewas identified by Palache(1928) as leu- from 3.57:l.7O to 3.17i 1.89.Material with the latter com- cophoenicite.This material consistsof veins up to 3 cm position was describedby Petersenet al. (1984),and has thick, associatedwith ,franklinite and sussexite.The unit cell parameters,a:4.827, b : 10.613,c : 8.116A, bulk of this material is alleghanyite:it consistsof massive a: 108.65'.A samplewith very similar composition,i'e': alleghanyitewhich forms euhedralcrystals on exposedsur- Mn2.sarMgr.rorZno.r roFe6.srrCar.r.r(SiOa)2(F,OH)r, was faces.Leucophoenicite is also present, both as epitaxial subjectedto crystal structure analysis(Francis, 1985a). His DUNNI MANGANESE HUMITES AND LEUCOPHOENICI,|ES 38t

Table 2. Microprobe analyses of alleghanyite and chondrodite, in order of decreasing Mn content; octahedral cations are calculated on the basis of Si : 2.

Sanple * SiO2 FeO MgO ZnO llno F H20 O=F Total M9 zn oB 1g2+ species Local ity

c6884 24.7 0,0 2.3 2.7 66.2 t.l 3.2 0.5 99.7 0.00 0.28 0.r6 4.s4 0.28 l.?3 4.98 Alleghanyite Franklin I47308 24.4 0.0 4.6 3.3 63.3 2.7 2.3 l.l 99.5 0.00 0.56 0.20 4.39 0,'15r.26 5.15 Alleghanyite Sterling Hill 146909 25.O 0.2 2.8 3.1 54.0 0.2 3.7 0.1 98.9 0.01 0.33 0.18 4.34 0,05 1.97 4.86 Alleghanyite Sterling HiIl R3878-2 25.r 0.0 4.8 3.4 64.2 1.2 3.2 0.5 10I.4 0.00 0.57 0.20 4.33 0.30 I.70 5.10 Alleghanyite Franklin c688s 24.9 0.0 5.9 3.4 62.6 L.6 3,0 0.7 100.7 0,00 0.71 0.20 4.26 0.41 l.6r 5.17 Alleghanyite Franklin 93336 25.9 0.2 3.9 3.9 63.5 tr, 3.9 0.0 I01.8 0.00 0.45 0.22 4.15 0.00 2.01 4.82 Alleghanyite Franklin

r37880 25.O 0.0 6.6 3.2 61.2 r.8 2.9 0.8 99.9 0.00 0.79 0.r9 4.15 0.45 1,55 5.I3 Alleghanyite Sterling HiLl 146201 25.0 0.3 6.2 3.2 60.4 2.2 2.1 0.9 99.1 o.02 0.74 0,19 4.09 0.56 r.44 5.04 Alleghanyite sterling Hill 147308 25.0 0.0 7 .A 3.4 60.r 2.5 2,6 l.r r00.3 0.00 0.93 0.20 4.0'10.63 r.39 5.20 Alleghanyite Sterling HiIl 145958 25.1 0.3 '1.36.7 3.5 s9.3 2.4 2,5 1.0 99.0 0.02 0.80 0.2r 4.00 0.60 1.38 5.03 AIIeghanyite Sterling Hil] 148618 25.4 0:2 3,6 60.0 2.5 2.6 l.I I00,s 0.0r 0.86 0.21 3.9s 0.62 L.37 5.03 Alleghanyite sterling Hill

134638 25.s 0.2 12.5 3,9 53.7 3.6 2.1 1,5 100.0 0.0r r.46 0.23 3.s7 0.89 I.l0 5.27 Alleghanyite SEerIing HilI JEM 74L2 25.5 0.4 L2.6 3.7 53.3 3.6 2.I 1.5 99.7 0.03 1.47 0.21 3.54 0.89 r,10 5.25 Alleghanyire sterling Hill 134866 25.7 0.2 72.2 2.3 2.8 1.0 99.5 0.01 r.42 0.21 3.54 0.56 r.45 5.18 AIIegbanyite Sterling Hill JEM1405 26.6 0.6 13.4 3.4 53.0 2.4 I.4 101.3 0.04 1.50 0.t9 3.37 0.78 r.20 5.I0 AIleghanyite sterling Hill JEM1404 26.A 0.5 13.l 3.7 51.9 2.4 1.4 t00.0 0.04 1.48 0.21 3.33 0.79 t,2t 5.06 Alleghanyite SterIing Hill

134745 26.6 0.4 14.r 3.4 50.5 3.7 2. I I.6 99.2 0.03 1.52 0.19 3.29 0.90 r.08 5.I3 AIIeghanyite SterIing Hill R8288 26.6 0.5 14.2 3.1 50.9 3.3 2.4 t.4 99,6 0.03 1.59 0.r7 3.24 0.78 1.20 5.03 AIIeghanyite sterling HiIl JEM1408 26.9 0.5 14.7 3.3 50.9 2,9 2.7 I.2 I00.7 0.03 r.63 0.18 3,2r 0,68 1.34 5.05 Alleghanyite sterfing Hill JEM 1411 25.7 0.4 15.3 J.t fu.o 5.2 2.5 t.3 100.9 0.02 r.71 0.r9 3.21 0.76 1.25 5.I3 Alleghanyite sLerLing HiIl 134638 26.4 0.3 14.5 4.r 50.0 3.8 2.2 1.6 99.7 0.02 1.64 0.23 3.2r 0,91 r.11 5.I0 Alleghanyite Sterling Hill L46229 26.7 0.4 14.? 3.2 50.3 3.3 2.4 I.4 99.6 0.03 r.64 0.r8 3.19 0.78 1.20 5.04 Alleghanyite Sterling HiIl Petersen 26.7 0.4 I5.0 J.' 'U.U J.I 2.5 1.3 99.9 0.02 1.58 0.19 3.17 0.'t3 r.25 5.06 Alleghanyite Sterling Hil.l

L44454 27.3 0.5 23.9 6.4 35.8 4.5 2.2 1.9 98.7 0.03 2.48 0.33 2.r1 0.99 1.02 4,95 Chondrodite Sterling Hill JEM2908 29,O 2.O 22.4 tI.5 30.s 3.6 2.6 1.s r00.1 0.12 2.30 0.59 1,78 0.79 r.20 4.79 cbondrodite sterling Hill KoIic-38 29,9 1.9 33.7 7.7 22.6 3.9 2.6 1.6 100.7 0.rr 3.36 0.38 r.28 0,82 r.r6 5.I3 Chondrodite slerlinq Hill

determinedlattice parameters,d : 4.815(2),b : 10.574(3\, crystal structure of this magnesianmanganhumite was de- c : 8.083(3)A,a : 108.74',are very similar to those of Pe- termined by Francis and Ribbe (1978)who found the ma- tersenet al. (1984).Francis (1985a)found this alleghanyite terial to be ordered with respect to Mn and Mg. End- to have ordered cations, with Zn and Mg in the smallest member manganhumite was subsequentlydescribed by M(3) octahedron,and Mn and Mg distributed such that Simmonset al., (1981)and Winter et al. (1983)from the the M(1) and M(2), octahedraare predominantlyoccupied Bald Knob manganeseprospect in North Carolina. by Mn with minor Mg. Of particular interest,in all of the Manganhumite, formerly unknown from Franklin, is analysesof alleghanyitepresented here, is the invarianceof massive,medium brown in color, and occurs in cm-sized Zn. Zinc is a common substituent in silicate phases at massesassociated with abundant franklinite and zincite. Franklin and Sterling Hill and its presenceis expected. the latter with much hetaeroliteexsolution and traces of However,in no caseis there an alleghanyitesample with- exsolution. Minor associatedminerals are out Zn, nor is there one with Zn in excessof theserela- alleghanyiteand calcite.Willemite is absent. tively invariant amounts.Although it is tempting to dismiss Manganoan humite was found at both Franklin and relatively small amounts of Zn as a common octahedral Sterling Hill. Some Franklin material consists of light substituent,such dismissalis not warranted here. Someof brown anhedral blebs, associatedwith minor franklinite, thesealleghanyites co-exist with zincite (ZnO), but the ma- willemite, and zincite in a rock which is predominantly jority have only willemite as an associatedZn-phase, and calcite.The analysislabeled Priuate (Table 3) is that of a thus may be saturatedwith respectto Zn. brown coating on what appearsto be tephroite. Becausethe amount of zinc is relatively invariant and Manganoanhumite from SterlingHill is markedly differ- because(as is shown below), the same relation holds for ent in texture. The samplesare from one occurrence,are leucophoenicite,there is adequatereason to propose that massive,medium brown in color, and associatedwith Zn is limited in alleghanyite and other humite-related franklinite, calcite,and minor willemite.Chondrodite is in- species.Fluorine is common in most alleghanyite,averag- timately associatedwith the humite. ing 40 mol% of the (OH) site in magnesianmaterial and Microprobe analysesof manganhumiteand manganoan generallydecreasing with increasingMn content. humite are presentedin Table 3. The analysesdemonstrate The last three analysesin Table 2 arc of manganoan much solid solution between Mg-rich material and that chondroditesfound in calcite-rich ore from Sterling Hill. with approximately 3.75 atoms of Mg per 7 octahedral The samplesvary in textureand associatedminerals. cations.Analyses of Franklin material show a gap between this compositionand that of the magnesianmanganhumite Manganhumite of Moore (1978).This gap, however,may be due to paucity Manganhumitewas originally describedfrom the Bratt- of data points in this seriesand may not reflect compo- fors Mine, Nordmark, Sweden,by Moore (1978),and the sitional gapsin the natural system.Fluorine is found in all 3EZ DUNN; MANGANESE HUMITES AND LEUCOPHOENICITES

Table 3. Microprobe analysesof manganhumiteand humite, in order of decreasingMn content; octahedralcations ate calculatedon the basisofSi : 3.

Sanple * SiO2 FeO MgO zno MnO CaO F H2O O=F Total Fe !t9 oH ttr2+ species

R4105 26.2 0.0 0.4 2.7 6s.6 1.8 1,2 2.0 0.5 99.4 0. 00 0.07 0.23 6.35 0.33 0.43 1.53 6.88 ltanganhmite Private 30.r 1.2 25.2 lO.8 29.7 0.2 2.4 t.9 1.0 r00,5 0.10 3.75 0.79 2.51 0.02 0.76 L.26 7.17 Hmite Bostw icI 30.9 r.8 29,5 13.4 2L.6 0.0 3.2 1,5 1.3 100.7 0.15 4.27 0.96 I.78 0.00 0.98 1.04 7.16 Hunite RBI OI 6 33.9 0.2 39.'t rO.2 14.3 0.0 3.r 1.9 1.3 r02.0 0.o2 5.24 0.67 1.07 0.00 0.87 l.I2 7.00 Humite RBIOI5 35.0 0.2 44.5 8.3 10.8 0.0 2.5 2.3 t.r 102.5 0.02 5.69 0.52 0.78 0.00 0.68 I.32 7.01 Humite c-n 34.7 0.9 44.3 9.8 9.5 0.0 3.0 2.0 r.3 102.r 0.05 5.57 0.52 0.70 0.00 0.82 I.15 5.95 Hmite

samplesand occupiesapproximately 22 to 49 mol% of the Franklin (Cook, 1969)and Bald Knob (Winter et al., 1983). (OH) site. The crystal structure was determined by Kato (unpub- lished;discussed by Ribbe, 1982). Sonolite D escription anil composition Introduction Microprobe analysesof sonolite are presentedin Table Sonolite, Mnn(SiOn)o(OH)r,was first describedby Yo- 4. They are best discussedin three clusters,defined in part shinaga(1963) from elevenlocalities in Japan.It has subse- by apparent limitations in the Mg and Zn contents.The quently been found elsewhere,including Steiling Hill and fust group of analysesrepresents samples only from Frank-

Table 4. Microprobe analysesof sonoliteand clinohumite,in order of decreasingMn content; octahedralcations are calculatedon the basis of Si : 4.

sanple I SiO2 Feo l49O ZnO MnO CaO It2O O=F Total Fe ng on r u2+ species

14903? 27.O 0.0 0,8 3.9 6s.4 0.7 0.0 2.0 0.0 99.8 0.00 0.22 0.40 8.39 0.110.24 r.80 9. lf sonolite c6992 26.7 0. r 2.4 2.0 65.7 0.8 L.2 t.4 0.5 99.8 0.0r o.54 0.22 8.34 0.130.57 1.40 9.24 sonolile JEU3068 26.3 0.0 0.5 2.9 64.4 2.0 1.0 1.5 0.4 98.2 0.00 0.r1 0.3r 8.30 0,33 0.48r.52 9. 05 Sonolite cr{12-l 26.9 0.0 0.9 2.2 65.5 2.4 0.0 2.0 0.0 99.9 0.00 0.20 0.248.25 0.380.00 r.98 9.O7 Sonolite 149037 27.0 0.0 0.8 3.9 65.4 0.? 0.0 2.0 0.0 99.8 0.00 0.180.43 8,2r 0,rr 0.00 1.98 8 . 93 sonol ile R1803 27.I 0.2 2.3 2.6 55.4 0.5 1.0 1.6 0.4 100.3 0.02 0.510.28 8.18 0.08 0.47 1.57 9.O7 Sonolite 14152 26.7 0.3 1.9 3.I 64.2 1. 0 L.2 1.4 0.5 99.3 0.04 0.420.34 8.r4 0.r6 0.57 1.40 9. l0 Sonolite .rEM35 87 26.'t 0. 0 1.4 2.6 62.8 2.6 r.2 1.4 0.5 98,2 0.00 0.310.29 8.00 0.42 0.57 1.40 9.02 Sonolite HAUCK.Fl,[4 25, 9 0.3 0.9 3.9 62.3 3.9 0.9 r.6 0.4 100.3 0.04 0.200.43 ?.84 0.49 0.42 1.59 9.0 0 Sonolite c2828-l 2't.O 0.0 1.5 3.7 50.7 4.I 1.I l. s 0.5 99.2 0.00 0.350.40 7.62 0.65 0.511.48 9.02 sonolite

JEU3080 27.3 0.0 4.6 2.7 63.0 0.0 0.9 1.6 0.3 99.8 0.00 I.01 0.29 7.82 0.00 0.42 L.56 9.12 sonolite JEM1545 21.7 0,0 5.7 2.8 6r.7 0.0 L.2 0.s 100.r 0.00 1.23 0.30 7.55 0.00 0.55 1.45 9.08 sonolite 143755 27.6 0.2 6.0 2.1 6r.4 0.0 r.0 1.5 0.4 100.1 0.02 I.30 0.29 7.54 0.00 0,46 1.55 9.r5 sonolite JEM1538 27.6 0.0 6.6 3.r 60.4 0.0 r,0 1.6 0,4 99.9 0.00 I.43 0.33 7,42 o.o0 0.46 1.54 9.18 sonolite 143587 27.5 0.2 7.6 3.1 s8,8 0.0 0.9 1.5 0.4 99,3 0.02 1.65 0.33 7.24 0.00 0.41 1.55 9.24 Sonolite 143755 27.8 0.2 8.3 3.3 58,9 0,0 1.0 t.6 0.4 100.7 0.02 1.78 0.35 7.18 0.00 0.46 1.54 9.33 Sonolite JEr.r1946 27.8 0.0 8.I 3.4 58.4 0.0 I.2 0.5 99.9 0,00 I.7{ 0.35 7.12 0.00 0,55 I.44 9.22 Sonolite

13333 29.2 r.3 15,9 9.5 4r.2 0.3 2.0 r.2 0.8 99.8 0.15 3.25 0.96 4.780.04 0.87 1.10 9.18 Sonolite L2965 29.3 1.4 15.4 10.0 40.7 0.2 1.8 1.3 0.8 100.3 0.15 3.34 1.01 4.71 0.030.78 1.r8 9.25 Sonolite R3522 29.2 1.5 r5,9 10.1 40.1 0.3 2.0 1.3 0.8 r00.6 0.r7 3.45 1.02 {.5s 0.04 0.87 1.19 9.33 Sonolite s-K 29.4 1.0 L7.4 8.8 39.9 0.1 L.7 1.4 0.7 99,0 0.lr 3.53 0.88 4.600.01 0.73 I.27 9.f3 sonoli.te R81028 29.6 t.2 L7.2 9.4 40.2 0.3 1.8 1.4 0.8 t00,3 0.14 3.47 0.944.60 0.04 0.77 r.26 9 . 19 Sonol ite RBt040 30.0 1.1 18.9 7.4 39.8 v.z r.o t.0 0.6 99.9 0.L2 3.76 0.73 4.500.03 0.67 1.33 9. 14 Sonol ite JEr4 2915 29.5 r.3 16.3 r1.9 35.4 0.4 1.6 I .4 0.7 98.1 0.r5 3.301.19 a.18 0.060.69 I.27 8.88 Sonolite

s-v 30, 8 0.8 22.2 8.8 36.2 tr. 1.6 1.4 0.7 10r.r 0.09 4.30 0.843.98 0.000.78 1.21 9.2L Clinohunite s-A 30.6 1.6 22.4 7.4 35.6 0.1 2.t 1.3 0.9 100.2 0.17 4.37 0.713.94 0.0r 0.87 l.l3 9.20 clinohumita s-P 31.4 1.0 25.3 8,8 31.7 tr, 1.8 1,5 0.8 r00.7 0.11 4.8r 0,83 3.42 0.00 0.73 L.27 9.17 clinohunite s-R 31.6 1.2 25.5 9.9 30.r tr. I.8 1.5 0,8 100,8 0.13 4.82 0.933.23 0.00 0.72 L.27 9.ll clinohmite s-N 31.5 1.9 25.9 10.2 28.7 0.1 2.2 1.3 0.9 r00,9 0.20 4.91 0.963.09 0.0r 0.88 r.l0 9.I7 clinohunite

14903 7 Frank I in A6socialed with jerrygibbsite, Ieucophoenicite, frankl.!nite, zincite' and willenite. c6992 Frank I in Asaociated with franklinite and zincite. JEM3068 Frankl in Associated with franklinite. zincite, and minor calcite and wlllenite. Rl803 Franklin Associated with franklinite and zincite. cr4l2-l Frankl in Asaocialed with franklinite, zincite, nanganosite, and leucophoenicite. 14152 Frankl. in Associated with franklinite, zincite, and willenite. .lEtit3587 Frankl in Associated with franklinite, nanganoaite, zlncite, and leucophoenicite. HAUCK.FMM Frank I in Associated with willenite- c2828-L Franklln Associated with willenite and ninor franklinite in veln assemblage.

r3333 Sterling Hill Associated with zincite, franklinite, calcite, and tephroite (rinned by sonolite). r2955 Franklin? Associated with zinclte, franklinite, calcite, and tephroite (rimed by sonolite). R3522 Franklin? Associated with zincite, franklinite, calcite, and lephroite. s-K SterIing HiIl Associated with zincite and willenite in a calcite-doninant rock. DUNNI MANGANESE HUMITES AND LEUCOPHOENICITES 383 lin. The samplesare characterizedby primary, varied,rela- tively invariant Zn content of thesesonolites is consistent tively simple assemblagesof severalspecies which may in- with that of the more Mn-rich samplesfound at Franklin. clude manganosite, willemite, sonolite, hetaero- The third group of analysesrepresents a very interesting litefranklinite exsolution intergrowths,jerrygibbsite, leu- assemblageinitially reported by Cook (1969).None of the cophoenicite,zincite (usuallywith abundant hetaeroliteex- samplesstudied herein had zinc contentsapproaching that solution),and a relative scarcityof carbonates.Specific as- reported by Cook (17.6 wt.% ZnO), using XRF analysis. semblagesare noted in Table 4. Thesesonolites have near Sonolite occurs as dark brown reaction rims on zincian end-membercompositions with minor solid solution of tephroite which has abundantwillemite exsolution.The as- other octahedralcations for Mn. Of specialinterest is the sociatedminerals are zincite,franklinite, willemite,and cal- relative constancyof zinc (averaging0.33 Zn per 4 Si), a cite.The compositionof this tephroite(average for #13333 feature noted herein in leucophoeniciteand alleghanyite. and #12965)is SiO, 31.6,FeO 1.8,MgO 13.4,ZnO 7.9, Also notable is the relatively high calcium content of sev- MnO 45.7,CaO 0.3,sum: 100.7wt.o/o, corresponding to eral samplesfrom a rather simple assemblage,in which an octahedral cation ratio of Mnr.rrMgo.u.Zno.r, approximately0.5 of the 9 octahedralcations are calcium. Feo.o5Cae.61,similar in zinc contentto the analysisof simi- The secondgroup of analysesrepresents euhedral crys- lar material given by Francis (1985b).Not all material of tals from secondaryseams and varied vein assemblagesat this composition occurs as mantling on tephroite; such Sterling Hill. The crystalsform on calcite-richfranklinite/ mantling was not observedon sample R81040 or sample willemite ore with no associatedzincite. There is minor S-K. The mantling of tephroite by sonoliteis interestingin secondarysphalerite. The sonolite crystals are complexly that a similar reaction, in isostructuralphases, was noted formed, of prismatic habit, and relatively abundant inas- by Mitchell (1978)who found titanian clinohumitereaction much as severalhundred specimenshave been preserved. rims on forsteritein kimberlitesfrom the Jacupirangaiar- RepresentativeSEM photomicrographsof severalof these bonatite in Brazil. Becausethe ratios of octahedralcations crystalsare shown in Figures I and 2. Crystals from this in thesesonolite rims are very similar to those of the un- assemblagewere studied by White and Hyde (1982),and derlying tephroite, the mantling may have occurred as a they found sample 143755to consistof crystalswhich were result of hydration of the primary tephroite (personalcom- either perfector had a moderateamount of faulting. munication,Carl Francis). The chemicalcomposition of thesecrystals is remarkably Compositionally, these sonolite reaction rims are similar in several respectsto that of the ordered alle- characteizedby different Mg:Zn: Mn ratios than thoseof ghanyite(Francis, 1985a) discussed above. The Mg and Zn the previoustwo groups.Magnesium is more than doubled contentsper 4 Si compareclosely with thosegiven per 2 Si in content relative to the previous group (e.g.:an average for alleghanyite,suggesting that this Mg:Zn: Mn ratio of 3.44Mg comparedwith an averageof 1.45Mg in group might also be ordered and responsiveto P-T conditions 2). A secondfeature of this clusteris the amount of Zn (0.96 inasmuchas both the orderedmagnesian alleghanyite and atom average)per 9 octahedralcations. The constancyof thesemagnesian sonolites are found in secondaryvein as- compositionof theserims from at least three varied para- semblages.Because the spacegoups of alleghanyiteand genesessuggests that thesesamples may represent,like the sonoliteare the same,such possibleordering in sonolite secondgroup, a possiblestable ordering of Mn, Mg, and may be basedon a similar schemeas that noted by Francis Zn betweensonolite and clinohumite. (1985a)for Sterling Hill alleghanyite.In addition, the rela- The last cluster of analvsesis of clinohumites.The sam-

Fig. l. Simple prismatic habit of magnesian sonolite from Ster- Fig. 2. Twinned magnesian sonolites from Sterling Hill, New ling Hill, New Jersey. Scale bar is 40 pm. Jersev. Scale bar is 200 zm. 384 DUNNI MANGANESE HUMITES AND LEUCOPHOENICITES ples come from one part of the Sterling Hill mine and are occur in restricted assemblages,several hundred leu- quite varied in texture, consisting of massiveaggregates, cophoenicitesamples were examined.The results of this veins, and disseminatedblebs of brown clinohumite. As- comparisonsupported the preliminary findings of Dunn et sociatedphases are zincite,franklinite, willemite,and abun- al. (1984) that leucophoeniciteis indeed widespread at dant calcite. Mantling such as describedabove is present Franklin and occursin a wide variety of assemblages,most on severalsamples, but the mantled phase was not ana- of which haveCa-bearing associated minerals. A very small lyzed;'it may be forsterite.Samples S-V and S-R are not- number of leucophoenicitesoccur without calcium-bearing able in that the clinohumiteis surroundedby reactionrims species.These Ca-poor leucophoenicitesare very uncom- of willemite which can be observed to have consumed mon; theyoccur in two typesof assemblages: clinohumite. 1. With franklinite, willemite,and zincite in assemblages usually devoid of other associatedphases. tf other silicate Generalobseruations on sonolite phasesare present,they are tephroite, sonolite, or jerry- In samplesfrom Franklin and Sterling Hill, the octa- gibbsite. hedral cations occur in two apparent compositionalclus- 2. With manganosite,zincite, and hetaerolite,in samples ters that may indicate specialordering schemes.These are: which are 80-95% manganosite(MnO) by bulk volume. (a)with Mg:Zn: Mn approximately: 1.5:0.3:7.2,and (b) This assemblagewas examinedin detail in searchof the with Mg: Zn: Mn approximately: 3.4:I.0:4.6. Zinc is ap- Mn-analogue of norbergite (MAN), which remains un- parently limited to different degreesin all analyses. is known in nature. The silicate phasesfound in this assem- more abundant in clinohumite,and calcium is more abun- blage were tephroite, sonolite, and Ca-poor leu- dant in sonolite; the latter likely due to cation radii re- cophoenicite.Leucophoenicite is the dominant silicate in quirements.Unlike the sonolite studiedby Kato (in Ribbe, this assemblage. 1982),Franklin and SterlingHill sonolitesdo haveappreci- able fluorine; it replacestp to 44 mol% of the possible Chemicalcomposition (OH),increasing with the Mg content. The analysesshown in Table 5 werechosen to show the extent of compositional variation. Examination of these Ieucophoenicite data permits a number of observations. Ot the 27 Introduction 1. Most leucophoenicitesare higbly calcic. analysesgiven,22 have Ca valuesin excessof 0.48Ca per 3 Leucophoenicite,(Mn,Znh(SiO4)3(OH)2, was originally Si. It should be emphasized,however, that this ratio of described from Franklin, New Jersey, by Penfield and calcic samplesis not reflectiveof the generalratio of calcic Warren (1899).Subsequent studies of its morphology were to non-calcic samples; calcic material is much morc publishedby Palache(1928, 1935\, and Moore (1967).The common. No samplescontained the very high (up to 14 crystalstructure was solvedby Moore (1970)who noted wt.%) CaO valuesreported by Cook (1969),using XRF that it has edge-sharing,half-occupied, silicate tetrahedra analysis.The abundanceof sampleswith valuesof 0.5-O.7 and is structurally distinct from the humite-groupminerals, Ca per 7 octahedralcations suggeststhat this is a some- with which it has strong compositional similarity and is what "stable" calcium content for sampleswhich form in frequently associated.Recently, White and Hyde (1983a, calcicassemblages. 1983b), using TEM techniques, showed that leu- 2. Zn is a constantconstituent of leucophoenicite.It is cophoeniciteis a memberof a family of structures(includ- presentin all analysesof leucophoeniciteobtained by this ing someborates and germanates),and supportedMoore's writer, including many not published here. It is relatively (1970)proposal of edge-sharing,half-occupied silicate tetra- invariant, amounting to approximately0.3 Zn per 3 Si. In hedra. The recent discovery of jerrygibbsite, a possible the last three analyses(Table 5), which are the most Mn- polymorph of Mn"(SiOo)n(OH)r,(Dunn et al., 1984)led deficient,zinc is slightly higher. However,no Franklin leu- those authors to speculatethat there might be additional cophoenicitewas found which was not Zn-beaing. Zinc membersof the leucophoenicitefamily, and that jerrygibb- was not reported in the Pajsberg,Sweden, leucophoenicite sitemight be oneof these. studiedby White and Hyde (1983b).However, their analy- sis of sampleC6800 from Franklin showedonly a trace of Description zinc whereasseveral analysesperformed as part of this Until recenly,leucophoenicite was known only from the study of severalcrystals of this samesample showed it to zinc deposit at Franklin, New Jersey;it has never been be homogeneousand contain 3.5-3.6 wt.o/oZnO, suggest- found at the geneticallyrelated Sterling Hill deposit,just a ing perhapsthere was undetectedZn in White and Hyde's few km distant, although bulk mineralogiesare very similar Pajsbergmaterial. The occurrencenoted by Dal Piaz et al. at both localities.White and Hyde (1983b)have now (1979)from the Valsesia-Valtournanchearea in the Italian shown that leucophoeniciteoccurs at Pajsberg,Sweden, western Alps, was shown by Winter et aJ. (1983) to be and Winter et al. (1983) have noted that a calcian alle- leucophoenicite,but it has uncertaincomposition. The con- ghanyite originally describedby Dal Piaz et al. (1979)is stancyof Zn in all the samplesstudied herein suggeststhat leucophoenicitebased on X-ray powder diffraction data. either it may be essentialto the species,or that there are Becausemany of the uncommon minerals at Franklin limits on the amount of Zn permitted in leucophoenicite, DUNN: MANGANESE HUMITES AND LEUCOPHOENICITES 3E5

Table 5. Microprobe analysesof leucophoenicite,in order of decreasingMn content; octahedralcations are calculatedon the basisof Si:3.

sample# si02 1,190 cao ZnO l1n0 HZO Total si Mg ca Zn Mn ,y2*

'l JEM31 26 25.6 1.4 0.5 4.3 65.8 2.6 00.2 3.00 0.24 0.06 0.37 6.53 7.20 JEM31 26 25.9 2.1 0.4 4.I 65.6 2.6 100.7 3.00 0.36 0.05 0.35 6.44 7.20 47909 26.0 0.2 1.6 3.8 64.9 2.6 99.t 3.00 0.03 0.20 0.32 6.34 6.89 c6238 26.0 1.7 0.0 4.1 64.6 2.6 99.0 3.00 0.20 0.00 0.35 6.31 6.95 JEM31 35 26.0 2.6 1.2 4.1 64.1 2.6 I00.6 3.00 0.45 0.15 0.35 6.27 7.22 'l0l.2 c6882 26.4 1.0 4.9 ?.9 63.4 2.6 3.00 0.1 7 0.60 0.24 6.'10 7.l l cl415-i 25.9 0.3 3.9 4.] 63.3 2.6 100.I 3.00 0.0s 0.48 0.35 6.21 7.09 I 44658 25.8 0.8 5.3 3.1 62.8 2.6 'l0l100.4 3.00 0.14 0.66 0.27 6.19 7.26 LOd/d ao.I u.o f,.9 3.1 62.7 2.7 .3 3.00 0.r0 0.55 0.26 5.97 6.99 r 35739 26.2 1.2 4.6 J.J OZ.+ t,O 100.3 3.00 0.20 0.56 0.28 6.05 7.09 '101 JEr431 37 26.2 1.2 5.5 3.4 62.3 2.6 . 2 3.00 0.20 0.67 0.29 6.04 7.20 c6800 26.2 1.2 4.6 3.6 62.2 2.6 I 00.4 3.00 0.20 0.s5 0.30 6.03 7.09 c6880 25.5 l.t 4.5 3.s 62.0 2.5 99.I 3.00 0.'19 0.57 0.30 5.'18 7.24 JEM3134 26.6 2.2 4.2 3.9 61.5 2.7 lot.l 3.00 0.37 0.51 0.32 5.88 7.08 95120 26.0 2.0 4.2 3.9 61.4 2.6 100.I 3.00 0.34 0.52 0.33 5.00 7.19

c6237 25.9 0.4 5.3 4.5 61.t 2.6 99.8 3.00 0.07 0.56 0.39 6.00 7.12 JEM3r]3 26.0 2.2 4.2 3.9 6l.0 2.6 99.9 3.00 0.38 0.52 0.33 5.96 7.19 JEM3] 28 26.2 0.7 5.7 5.',1 6] :0 'l0ltol .3 3.00 0.'12 0.70 0.43 5.92 7.17 R3878-l 26.9 I.6 5.6 3.8 60.9 a.o .4 3.00 0.27 0.67 0.3] 5.75 7.00 JEM3098 26.3 0.6 6.2 3.7 60.5 2.6 99.9 3.00 0.'10 0.76 0.3] 5.84 7.01

c2920 26.1 0.5 7.0 2.7 60.4 2.6 '100.99.3 3.00 0.09 0.86 0.23 5.88 7.06 116857 27.0 1.7 5.6 3.6 59.7 2.7 3 3.00 0.28 0.67 0.30 5.62 6.87 84964 27.0 3.3 4.7 4.3 59.5 2.7 101.5 3.00 0.55 0. 56 0.35 5.60 7.06 JEM3132 26.1 2.0 5.7 3.7 59.0 2.6 '100.499.r 3.00 0.34 0.70 0.31 5.74 7.09 JEM3135 26.5 2.4 s.3 5.2 58.4 2.6 3.00 0.41 0.64 0.43 5.60 7.08 149543 26.4 2.4 5.3 f,.o at.a z.o 99.8 3.00 0.4'l 0.64 0.47 5.54 7.06 R6602-l 26.4 3.1 6.6 4.4 56.3 2.6 99.4 3.00 0.53 0.80 0.37 5.42 7.12

* - H20calculated based on 2(0H)per 3.00 Si. Fe and F presentonly as traces or absent: Accuracyof data: r3%of the amountpresent. or both. No samplescontained the very high zinc content the original description, several additional sampleswere (up to 8 wt.%oZnO) reported by Cook (1969)using XRF found and studied.Their paragenesesare similar in several analysis. respectsto the original samples,i.e.: they are simpleassem- 3. Fluorine is essentially absent in leucophoenicite. blagesconsisting of only zincite, willemite, tephroite, and Some sampleshave tracesof F, but such traceswere well franklinite, or leucophoenicite,and are notable for the lack within the error of microprobedeterminations. of any Ca-bearing species.However, of the five known The available evidencestrongly suggeststhat Ca, Zn, jerrygibbsitesamplos, four are texturally distinct from each and F/OH may play critical roles in the composition of other, suggestingthey wereto someextent spatially distrib- leucophoenicite.Because most samplesare highly calcic, uted in the Franklin orebody.Zincrte is presentin all sam- the implication is that Ca might be a cation of preference ples. for leucophoenicite.One might speculatethat it should be Microprobe analysesof jerrygibbsite are presentedin ordered. inasmuch as Ca is ordered in all olivine-related Table 6; the two analysespreviously published by Dunn et structures investigated to date (Lumpkin et al., 1983; al. (1984) are included for comparison. Like leu- Ribbe, 1982).The affinity of Ca for leucophoeniciteremains cophoenicite,jerrygibbsite appears to be a phase which enigmatic. might have essentialzinc. It is noteworthy that Mn does The constancyof Ztr, at least in Franklin samples,re- not exceed32 of the possible36 octahedralcations (full cell mains uninvestigated.The availableevidence suggests that contentswith Z :4), and that Zn approximates2 atomsin Zn may play somerole in the formation of leucophoenicite the full cell. The apparently low Mg content of both leu- and the stability of this phaserelative to membersof the cophoeniciteand jerrygibbsiteis noteworthy,especially be- humite group, where bulk rock compositionsare zinqian. causeMg is easilyaccommodated in the Mn-humites. Similarly,the absenceof fluorine might indicatethat OH/F ratios affect the selectiveformation of leucophoeniciterela- General observations on specific cations tive to the F-bearing manganesehumites. These lines of reasoningwould apply equally to jerrygibbsite. Manganese No end members are found among the Mn-humite Jerrygibbsite speciesat Franklin or Sterling Hill, in large part due to Jerrygibbsite,ideally (Mn,Zn)n(SiOr)n(OH)r, was first de- ubiquitous Zn substitution and abundant Mg in many scribedfrom Franklin by Dunn et al. (1984).Subsequent to samples.Manganese is restrictedin leucophoenictte(5.42= 386 DUNN; MANGANESE HUMITES AND LEUCOPHOENICITES

Table 6. Microprobe analysesofjerrygibbsite, in order ofdecreasing Mn content; octahedralcations are calculatedon the basis of si:4.

t+ Sample# Si 02 FeO MSO CaO ZnO MnO HZl Total Fe Mg rM-'

c1417 26.9 0.2 1.1 2.0 5.3 62.3 2.0 99.8 0.02 0.24 0.32 0.58 7.85 1.98 9.0]

c699',1 26.9 0.2 3.0 1.6 3.2 6l.8 2.0 98.7 0.02 0.67 U.4C U. Jf, 7.79 1.98 9.08 R18772 27.1 0.3 1.4 0.4 3.9 64.1 2.13*99.3 0.04 0.3] 0.06 0.43 8.02 2.10 8.86 c3209 26.6 0.3 l.l I.0 5.3 62.1 2.25* 98.6 0.04 0.25 0.16 0.59 7.91 2.26 8.95 Average/4 0.03 0.37 0.19 0.49 7.89 8.97

* analysesfrom Dunn et al., 1984;water by Penfieldmethod.

6.53 Mn per 7 octahedralcations) and jerrygibbsite(7.79- Mn: Mg ratios, but at Franklin, also to the Zn content, 8.02Mn per 9 octahedralcations). Although alleghanyiteand sonolite are both known from other depositsas zinc-freephases, neither leucophoenicite Calcium nor jerrygibbsite has been shown to be zinc-free.Hence, Calcium is common to both jerrygibbsite and leu- leucophoeniciteand jerrygibbsitemay be characterizedby cophoenicite,but among the humites only sonolite accepts essentialzinc. or some limitation on the amount of Mn appreciableCa (up to 0.65Ca per 9 octahedralcations). permitted, or other factors, such that thesephases might not be stablein nature as manganeseend-members. Iron In addition, the equilibrium relations which favor the The Mn-humites at theselocalities have minimal Fe sub- formation of leucophoeniciteor jerrygibbsite rather than stitution. Clinohumite acceptsup to 0.2 Fe per 9 octa- the manganesehumites remain unknown. Similarly, the ef- hedral cations. fects of zinc on the phase relations for the Mn-humites remain unstudied,and very little is known of the partition- Magnesium ing of cationsamong the co-existingMn-humites. All the Mn-humites contain Mg, which apparentlygen- eratesseveral ordered intermediatephases. Magnesium is Acknowledgments apparently quite restricted in both leucophoeniciteand Althoughthe analyzedspecimens are mostly from Institutional jerrygibbsite. collections.the breadthof the observationsherein would not have been possiblewithout much dedicatedeffort on the part of Mr. Zinc Richard Bostwick,to whom I am deeplyindebted. I wish to thank There is a "threshold" level of 0.24.4 Zn atoms per xSi Drs. Carl A. Francis,Paul B. Moorg Donald R. Peacor,Paul H. Ribbe, and Timothy J. White for critical readingsof this paper.I in all the studied samples (x:2 for alle- thank Mr. John L. Baum, Mr. and Mrs. Richard Hauck, Mr. John ghanyite/chondrodite, 3 for manganhumite/humite/leuco- Kolic, and Mr. StephenSanford for providing samplesfor study. phoenicite,and 4 for sonolite/clinohumite/jerrygibbsite).In This project was supported,in part, by a grant from Mrs. E. both leucophoeniciteand alleghanyite, this "threshold" Hadley Stuart, Jr. I thank the Trusteesof the Franklin Mineral level is relatively constant for all studied samples.Zn is Museumfor their continuedassistance. apparentlyordered in some Mg-bearing alleghanyitesand sonolites.No samplesarc zinc-free. References (194) Fluorine Campbell Smith, W., Bannister,F. A., and Hey, M. H. Banalsite,a new barium feldspar from Wales. Mineralogical Both jerrygibbsite and leucophoeniciteare fluorine-free. Magazine,27,3346. Fluorine is common to the Mn-humites at Franklin and Cook, D. (1969)Sonolite, alleghanyiteand leucophoenicitefrom Sterling Hill, and is roughly proportional to the Mg- New Jersey.American Mineralogist, 54, 1392-1398. content. Dal Piaz.G. V., Battistini, G. di, Kienast,J. R., and Venturelli,G. It should be emphasizedthat many of these chemical (1979)Manganiferous quartzitic schistsof the piemonteophio- featuresmay be solelyresponsive to conditionsat Franklin lite nappe. Memoire degli Instituti di Geologia e Mineralogia and SterlingHill. dell' Universitadi Padova,32, l-24. Dunn, P. J., Peacor,D. R., Simmons,W. 8., and Essene,E. (1984) Jerrygibbsite, a new polymorph of Mn"(SiOn)o(OH), from Unresolved matters Franklin, New Jersey,with new data on leucophoenicite.Ameri- can Mineralogist, 69, 546-552. The crystal-chemicalrole of Zn in the Mn-humites is Dunn, P. J. and Ramik, R. A. (1984)Magnussonite: new chemical deservingof careful investigation.Not only do both so- data,an occurren@at Sterling Hill, New Jersey,and new data nolite and alleghanyiteexhibit two apparentchemical clus- on a related phasefrom the Brattfors Mine, Sweden.American ters each,but it appearsthat theseare related to not only Mineralogist,69, 800-802 DUNN: MANGANESE HUMITES AND LEUCOPHOENICITES 3E7

Francis, C. A. (1985a)Crystal structure refinementof magnesian Rentzeperis,P. J. (1970) The crystal structure of alleghanyite, alleghanyite.American Mineralogist, 182-185. Mn r [(OH), l (SiOn)r].Zeitschrift fiir Kristallographie,132, l-18. Francis,C. A. (1985b)New data on the forsterite-tephroiteseries. Ribb€, P. H. (1982)The humite seriesand Mn-analogs.Orthosili AmericanMineralogist, in press. cates, Vol. 5, Reviewsin Mineralogy, 231-274. Mineralogical Francis, C. A. and Ribbe, P. H. (1978)Crystal structuresof the Societyof Americ4 Washington,D. C. humite minerals:V. magnesianmanganhumite. American Min- Rogers,A. F. (1935)The chemicalformula and crystal systemof eralogist,63, 87 4-877. afleghanyite. American Mineralogist, 20, 25-35. Fukuoka M. (1981)Mineralogical and geneticalstudy on alaban- Ross,C. S. and Kerr, P. F. (1932)The manganeseminerals of a dite from the manganesedeposits of Japan. Memoir Faculty vein near Bald Knob, North Carolina. American Mineralogist, ScienceKyushu University,Series D., Geology,No. 4, 207-251. 17,1-18. Mitchell, R. H. (1978)Manganoan magnesianilmenite and tita- Simmons,W. B., Peacor,D. R., Essene,E. J., and Winter, G. A. nian clinohumite from the Jacupirangacarbonatite, Sao Paulo, (1981) Manganeserninerals of Bald Knob, North Carolina. Brazil. AmericanMineralogist, 63, 544-547. MineralogicalRecord, 12, 167-l'l l. Moore, P. B. (1967)On leucophoenicites.I. A note on form devel- White, T. J., and Hyde, B. G. (1982)Electron microscopestudy of opments.American Mineralogist, 52, 122G1232. the humite minerals:II. Mn-rich specimens.Physics and Chem- Moore, P. B. (1970)Edge-sharing tetrahedra in the crystal struc- istry of Minerals,8, 167-184. ture of leucophoenicite.American Mineralogist, 55, 1146-1166. White, T. J. and Hyde, B. G. (1983a)A description of the leu- Moore, P. B. (1978)Manganhumite, a new species.Mineralogical cophoenicitefamily of structuresand its relation to the humite Magazine,42, l3J-136. family. Acta Crystallographica,839, t0-17. Palache,C. (1928)Mineralogical notes on Franklin and Sterling White, T. J. and Hyde, B. G. (1983b)An electronmicroscope study Hill, New Jersey.American Mineralogist, 13,297-329. of leucophoenicite.Arnerican Mineralogist, 68, 1009-1021. Palache,C. (1935) The minerals of Franklin and Sterling Hill, Winter, G. A., Essene,E. J., and Peacor,D. R. (1983)Mn-humites SussexCounty, New Jersey. U. S. Geological Survey Pro- from Bald Knob, North Carolina: mineralogy and phaseequi- fessionalPaper, 180, 103-105. libria. AmericanMineralogist, 68, 951-959. Penfield,S. L. and Warren, C. H. (1899)Some new mineralsfrom Yoshinaga,M. (1963)Sonolite, a new manganesesilicate mineral. the zinc mines at Franklin, N. J., and note concerning the Memoir Faculty Science,Kyushu University, Series D, Ge- chemicalcomposition of ganomalite.American Journal of Sci- ology,14, l-21. ence,8, 339-353. Petersen,O. V., Bullhorn, J., and Dunn, P. J. (1984) A highly magnesianalleghanyite from SterlingHill, New Jersey.Mineral- Manuscriptreceioed, April 24, 1984; ogical Record,15, 299-302. acceptedforpublication, October 12, 1984.