AmericanMineralogist, Volume 67, pages 841-845,1982 Retzian-(Nd),a new mineral from SterlingHill' New Jersey and a redefinition of retzian PBre J. DuNrl DePartmentof Mineral Sciences Smit hs onian Instit ution Washington,D. C.20560 eNn B. Denro SrunueN Department of Mineralogy and Geology Royal Ontario Museum, 100 QueensPark Toronto, Ontario, Canada Abstract Retzian-(Nd)is a new mineralfrom the SterlingHill Mine in Ogdensburg,New Jersey.It is orthorhombic,Pban, with a : 5.690,b = l2.l2,and c = 4.8'744-The dominantrare earth is Nd and the ideal formula is MnzNd[(OH)+AsO+].Retzian-(Nd) occurs as euhedral parallel crystalswirh forms {001},{010}, {150}, {130}, {1 l0}, {201},and {021},and is elongate p: 1.782, to u001.optically, retzian-(Nd)is biaxial (+) with refractiveindices a: 1.774, -10.002); : is weak r ( v. and 7 = t.iSS (all 2V. 6911;'measured, 7l'calculated; dispersion Retzian-(Nd)is found with rhodochrosite,willemite, sonolite,calcite, barite and chloro- phoenicite in three separateparageneses at Sterling Hill. Retzianis re-examinedand redefinedas Mn2ce[(oH)aAsOa]with Ce > Nd > La, based on microprobe analysis of type material. The data presented here confirm the proposed crvstal structure. Introduction retzianto ascertain its composition and to simulta- neouslydescribe the SterlingHill material. A frag- Retzian was originally described by Sjogren ment of the type retzian from the collection of (1894)as a new manganesecalcium arsenatefrom Hjalmar Sjogrenwas obtained through the courtesy the Moss mine, Nordmark, Varmland, Sweden. of Dr. Bengt Lindqvist of the NaturhistoriskaRiks- The chemical analysis by Mauzelius in Sjogren museetin Stockholm.This fragmentis now recata- (1894)was performedon only 0.0795g of material, loguedunder Nuun #145882. owing to the extreme paucity of samples' The The presentstudy determinedthat the type mate- analysiswas admittedly incomplete with 0.0082g of rial is Ce-rich and the new material from Sterling is unidentifiedresidue, part of which Sjogren (1897) Nd-rich. This necessitatesa redefinitionof retzian later ascribed to the presenceof rare earths. as MnzCe(AsO+)(OH)aand the naming of the Ster- Retzianwas subsequentlyre-examined by Moore ing Hill materialas retzian-(Nd),in accordancewith (1968) who presented crystallographic data and Levinson's rules for the naming of rare-earthana- proposedthe tentativeformula MnzY(AsO+XOH)+' logs of known species(Levinson' 1966).The no- assigningthe rare-earth content to yttrium on the menclature outlined above was submitted to the basisof Gladstone-Dale calculations. Moore (1967) IMA Commissionon New Minerals and Mineral alsodescribed the crystal structureofretzian' care- Names. It was the judgment of the Vice-Chairman fully pointing out that "the structure analysis of that this redefinition of retzian and the designation retzian is largely a study of a compound with an of the name retzian-(Nd) for the Nd-analog required unknown composition." no vote, being a simple applicationof Levinson's The recent discovery of a second occurrence of rules already accepted by the Commission. The "retzian" at the Sterling Hill Mine, Ogdensburg, holotyperetzian-(Nd) is depositedin the Smithsoni- New Jersey,prompted an analytical investigation of an Institution under catalog #143762. Small por- 0003-004x/82/0708-084| $02. 00 E4l u2 DUNN AND STURMAN: RETZIANINd) were orientedwith the precessioncamera. Crystal drawings of typical crystals are presentedas Figure 1, and the angletable is given in Table l. Because the signalsobserved on the goniometerwere very poor, the accuracyof these measurementsis only -ts1-2". The predominant forms on retzian-(Nd) are the same as those noted by Sjcigren(1897) on retzianfrom the Moss Mine. However, the crystal habit is markedly different inasmuch as retzian-(Nd) is elongateparallel to [100],and retzian is elongate parallelto [001].In addition to the forms shown in Figure l, very thin faces of {021} and {150} were observedon only one crystal. The unit cell parameterswere provided by Moore (1967)and the unit cell parametersand spacegroup extinctions determined in our study of the Sterling Hill retzian-(Nd) are in excellent agreementwith Moore's data. We used 0-level precessionphoto- graphsto orient the crystals subsequentlystudied with the goniometer and spindle stage.The unit cell parametersfor retzian-(Nd) were refined with data from a 114.6mm diameterGandolfi camera powder Fig. l. Crystal drawings of typical retzian-(Nd) crystals from photograph obtained using NBS silicon as an inter- SterlingHill, New Jersey. nal standard. The refined parameters are given in Table 2 and the X-ray powder diffraction data are tions of the holotype (loose crystals) have been given in Table 3. depositedin the Royal OntarioMuseum, The Amer- ican Museumof Natural History in New York, The Physicaland optical properties Mineralogical Museum at Harvard University, The Retzian-(Nd)occurs as pinkish-brownto reddish- GeologicalSurvey of Canada,and the British Muse- brown crystals and aggregatesof crystals. Where um (N.H.). color zoning is evident, the interior of the crystals Retzian-(Nd) has the darker color, but it was not possible to analyzethese few zoned crystals to establish com- Six crystals of retzian-(Nd) from Sterling Hill positional correlations. The streak is very light were studied on the optical goniometer and two brown. The luster is vitreousto dull on crystalfaces and vitreous on fracture surfaces. There is no Table l. Angle table for retzian-(Nd) from Sterling Hill discerniblecleavage, but the crystalstend to break along parallel planes due to parallel growth. The orthorhombic:a = 5.690, b = lZ,1?, c = 4.874I hardnessis approximately3-4 on Mohs' scale.The Measured Ca]cul ated fracture is uneven. The density, measuredusing heavy liquid techniques,is greater than 4.2 g/cm3, but could not be more reliably estimated due to extreme paucity of material and the fact that some c {00i} oo oo oooo' crystals contain cavities. The density calculated b {0]0} oo 9oo oooo' goooo' using the chemical analysis and cell parameters t { 150} ?40 9oo ?3o04' 9oooo, (Table 2) is 4.45 dcmt, suggestingthat the 4.15 -.o g/cm3 (1894) n {130} JC 9oo 35o?z' goooo' of Sj<igren was low. This low value .-o could have been due to the cavities in the m {l'10} o5 9oo 64osl' 9oooo, crystals noted above,or to interstitial spacesbetween crys- d {201} 9oo goooo' 59o sgo43' tal aggregates. e {02]} oo 38', oooo' 38o+a' Optically, retzian-(Nd)is biaxial (+). The optical data are presentedin Table 2. Determinations were DUNN AND STURMAN: RETZIAN4Nd) 843 Table 2. Crystallographic and optical data for retzian-(Nd) and cateanalyses for Mn and As, usingother standards, retzran confirmed the analysesfor these elements.Water was determinedby DTA-TGA on 3.2 mg of a non- Retzian - (Nd) Retzlan Ster'ling Hill Sweden type sample of Swedish retzian; this resulted in a loss of 8.3 percentH2O between230 and 570"C, in ldeal fomula: l4n2Ndl(0H)4As04l tlnZCet(0H)44s04l good agreementwith Mauzelius' determinationof Unit ce'll parareters: a s.ogo(s)I s.ozo1slff * 8.4 percent and the theoretical value of 7.88 per- D 12.r2(r) r2.03(1) cent. The resultantanalyses are presentedin Table c 4.874( 3) 4.863(4) 4. Space grcup: Pban Pban Retzian Refractive indices: d | .774(2) 1.777(5) ** (in B 1.782(2) r .788(5) The original analysis of retzian by Mauzelius The System of I r.798(2) r.8oo(s) Sjcigren,1894) is readily available in Mineralogy (Palacheet al., 1954)and is thus not = opti c axi al angle: (meas.) 2v, 69(l)o large, positive reprinted here. Although it was incomplete and = (calc. ) zuz 7f -'z contained misidentified and unknown components Dispersion: r < v, weak r < v, weak (10.3 percent unidentified, 19.2 percent CaO, 4.3 percentinsoluble residue), it was remarkablyaccu- orientation and pleochrcisn c ll x,yellw 9ll x' colorless to yel low rate for AszOs, H2O and trP* cations, especially that it was performed on only 0.0795g b ll Y, reddish- b ll Y, yeilw to considering bMn brcwn g ll z' brown a ll Z, red-brown to crimson Table 3. X-ray powder diffraction data for retzian-(Nd) Absorption: z>Y>>x z>Y>x l/ lo d (obs.) gL( cal c) hk'l * --Crysta'llographic data for retzian from l,,loore(1967). **--0ptical data from Larsenand Beman(1934) and Sjdgren (1897). ?0 6.05 6.060 020 30 4.89 4.874 001 5 3. 809 3.798 021 madewith the spindle stageon crystals previously 60 3.534 3.540 ill 't5 oriented with the precessioncamera. Principal re- 3.296 3.294 130 fractive indices were measured in Na light by the l5 3.028 3.030 040 't5 immersion method and oils were immediately 2.849 2.845 200 checked using an Abbe refractometer. The optical 100 2,726 2.729 l3l previous- 5 2.574 2,575 220 data are in excellent agreementwith those 2 2.455 2.457 201 ly obtained for retzian from Sweden (Table 2). 5 2.344 2,345 l4l Chemistry 2 2,259 2.261 022 l5 2.078 2.074 240 Analytical techniques 2 2.029 2,028 I 5',1 2 2.020 2.020 060 Crystals of retzian-(Nd) from Sterling Hill and 'L959 retzian from the Moss Mine, Sweden, were chemi- t9 I .963 132 cally analyzed using an ARL-sEMeelectron micro- r .905 I qoo 042 30 1.857 I .851 202 probe utilizing an operating voltage of 15 kV and a 5 1,779 1,770 222 beamcurrent of 0.15 pA. The standardsused were 5 1,754 1,749 3l'l manganitefor Mn; synthetic olivenite for As; syn- Fe, Mg and 2 1.723 thetic ZnO for Zn; and hornblende for 2 1.646 Ca. The rare-earth synthetic glass standards of 20 1,625 Drake and Weill (1972) were utilized as standards 2 I .583 in l5 I .570 for the rare earth elements.La lines were used l5 I .556 the analyses and special attention was given to 20 1.463 (plus -20 lines to 1.108) possible interferences and background effects.