Sundiusite, a New Lead Sulfate Oxychloride from Lingban, Sweden

American Mineralogist, Volume 65, pages 506-508, 1980

Sundiusite,a new lead sulfate oxychloridefrom Lingban, Sweden

Pnrp J. DUNN

Department of Mineral Sciences, Smithsonian Institution llashington, D. C. 20560

AND ROLAND C. ROUSE Department of Geology and Mineralogy, University of Michigan Ann Arbor, Michigan 48109

Abstract

Sundiusite,Pbro(SO4)Cl2Or, is a new mineral from Ldngban, Sweden.It is monoclinic, C2, Cm,orA/m,witha:24.67(l),6:3.781(l),c: ll.S8l(5)A,B:100.07(4)",andZ:2. The strongestlines in the X-ray powderpattern are (Al, hk|)2.981I0 510;2.7378113;3.101 6 602,603;3.W 6 800,403;6.10 3 400;3.74 3 I 10.Sundiusite occurs as plumoseaggregates of white to colorlesscrystals with an adamantineluster. The Mohs hardnessis about 3, and there is a perfect {100} cleavage.Optically, it appearsto be biaxial (+) with all indices greater than 2.10;lath-shaped fragments are length-slow.The observedand calculatedden- sitiesare 7.0 and 7.20g/an3, respectively.The mineral doesnot fluorescein ultraviolet radiation. The composition,as determinedby electronmicroprobe, is PbO 93.1,FeO 0.5, SO33.5, Cl 3.0,less O = Cl 0.7, total 99.4weight percent,which yields the ideal formula Pbro(SO4)Cl2Ot. The composition and cell geometry suggesta structural relationship to the nadorite group. Sundiusite is known only from Ldngban and is identical with Flink unknown #284. The name is for the late Nils Sundius.

Introduction not recognized by the Subcommitteeon Amphiboles, This new mineral specieswas found severalyears IMA, in its recent systemizationof amphibole no- ago on a specimen in the collections of the Smithso- menclature (Leake, 1968) and indeed "sundiusite" nian Institution. The new specieswas later identified was not even included in its list of amphibole names as one of those minerals of unknown identity noted which should be abandoned.Since this compound is from Lingban by the mineralogist and collector, unknown as a natural mineral and since the name justified Gustav Flink (1849-1931).Flink published many has not gained popular acceptance,we feel lists of Lingban minerals which he consideredwor- in using sundiusite for the new speciesfrom Ling- thy of further investigation.The referencesto these ban. The mineral and name have been approved by lists are given in a report on the statusof the "Flink the IMA Commissionon New Minerals and Mineral unknowns" by Moore et al. (1971'5. Names.The type spccimenis preservedin the Smith- We take pleasurein naming this new mineral sun- sonian lnstitution collection under catalog#NMNH diusite after the late Swedishmineralogist Nils Sun- 134984. dius (1886-1976)n recognitionof his numerouscon- tributions to the study of Ldngban mineralogy Physicaland optical properties including his classicstudy of the manganiferouspy- Sundiusite occurs exclusively as plumose aggre- roxenoids (Sundius, l93l). The pronounciation of gates of white to colorlesscrystals up to 8 mm in the name is sDri-d-e-us-ite.The name sundiusitehas length. The aggregatesare composedof overlapping been previously used to denote the hypothetical plates, which are slightly offset from one another in a sodic-calcic amphibole, NaCaNaMg3AlrSLOrr(OH), diverging manner. The streak is white and the luster (Phillips and Layton, 1964).However, this name was adamantine.There is one perfect cleavageparallel to 0003-004x/80/0506-0506$02.00 506 DUNN AND ROUSE: SUNDIUSITE s07

{100}. The mineral is quite brittle, breaking easily Table l. Electron microprobeanalysis of sundiusite into lath-shapedfragments, whose longest dimension SUNDIUSITE Theoreti ca1 is parallel to the b crystallographic axis. A possible Pblo(s04)cr2o8 second cleavagemay exist parallel to {001} but is very poorly developed.The Mohs hardnessis ap- Pb0 93.1 94.30 proximately 3. The density, determinedusing a Ber- Fe0 0.5 man balance and temperaturecorrection, 7.0+0.2 s0. 3.5 3.38 is J g/cm', in good agreementwith the calculatedvalue cl 3.0 3.00 '7.20 '1 of E/cm'. Optically, sundiusite appears to be Total 100I 00.68 biaxial (+) with refractiveindices all>2.1. The maxi- Less0 = Cl 0.7 0.68 mum birefringence,determined with a tilting com- Total 99.4 100.00 pensator, is 0.070. Cleavage laths are length-slow. There is no responseto ultraviolet radiation. Sun- Accuracyof data: t3% of the amountpresent. Quantities given diusite, along with blixite, occurson fracture surfaces are in weight percent. of an ore consistingof braunite,hausmannite, calcite, and manganoanbiotite. It is the last mineral of this assemblageto form. There is also a prominent subcell with A : 24.67,B Sundiusiteis similar in appearanceto severalother : 3.?81,C : c/3 : 3.960A,and B: 100.07o.Cell minerals, the most notable of which are hydro- parameters were refined by least-squares from cerussiteand mendipite. The resemblanceto mend- Debye-Scherrerdata utilizing NBS silicon (a : ipite, PbrOrClr, from the Mendip Hills, England is 5.4309A)as an internal standard.The X-ray powder particularly striking. Although neither mineral fluo- diffraction data are given in Table 2. rescesunder ultraviolet radiation, the calcite associ- ated with each has a similar fluorescence.which ac- powder difraction data for sundiusite centuatesthe resemblancebetween mendipite and Table 2. X-ray sundiusite.This has led to someconfusion. a matter dobs oca hkl Iobs ocal hkl lobs I "obs which will be discussedin a subsequentsection.

The subcell dimensions of sundiusite suggest a two minerals are identical (Flink #285 is blixite). relationship betweenthe new mineral and members However, we note that Moore et al. (1971) attribute of the nadorite group. As shown in Table 3, the lat- #284 ro mendipite on the basisof density and single- tice parametersof orthorhombic nadorite,perite, and crystal X-ray photographs.Subsequent to our char- blixite are related to those of synthetic tetragonal a;clerizationof sundiusite, a number of specimensof nadorite (SN) such that a = c = asNJ2 and b = cr* Flink #284 were located in the Flink collection at or 2csN.In other words the basic geometrical unit Harvard University. Both sundiusiteand mendipite common to all of them is either tetragonalor pseudo- were identified by powder X-ray photography on tetragonalwith parametersA = 4 andc = l2A. This these specirnens,but the two minerals do not occur correspondsto the sundiusitesubcell with its A pa- togetheron any one specimen.Hence, Flink number rameter halved. It may also be noted that nadorite 284 was probably assignedto two separateminerals, and its congenerspossess a single perfect cleavage which would have been difficult for Flink to distin- perpendicular to their 12 (or 25) A translation, re- guish by sight or density measurements,the densities flecting the layered character of their crystal struc- of sundiusiteand mendipite being 7.20 and 7.22 e/ tures (Giuseppettiand Tadini, 1973).Sundiusite also cm', respectively.Mendipite has also been reported possessesa single perfect cleavagenearly per- from Lingban by Gofli and Guillemin (1953). pendicular to its 25 A translation. From the fore- going similarities we infer that sundiusite is a lead Acknowledgments oxychloride with a layered structurerelated to those The authors are indebted to Mr. B. Darko Sturman of the Royal of the nadorite group. Ontario Museum for his help with this study. We also thank Dr. Francis of the Harvard Mineralogical Museurn for If sundiusiteis indeed related to nadorite as pro- Carl University assistance in finding additional specimens of sundiusite in the posed,the presenceof the sulfateion is somewhatin- Harvard collection of Lingban minerals. We are grateful to Mr. congruous,as the nadorite structure containsno tet- Charles Obermeyer, Mr. Richard Johnson, and Mr. Frank rahedral anions. An explanation may be that the Walkup for technical assistance. This work was supported, in part, nadorite minerals are a part of a larger family of bis- by a grant from Mrs. E. Hadley Stuart, Jr. muth, lead, and antimony oxyhalides(Structure Re- References ports,1947-1948,p. 305-320),some of which contain (1924) pA complex Flink, G. F

Formula Space Group Unit Cell (A) 289-30l. ab Phillips, R. and W. Layton (1964) The calciferous and alkali am- Nadoritea Pb5b02ct Crncn 5.60 12 24 5 45 phiboles. Mineral. Mag., 33, 1097-1109. h Sillen, L. G. and L. Melander (1941) X-ray studies on the oxyha- Peri te" PbBi02cr Cnm 5.63 12-42 5.58 lide minerals nadorite (ochrolite) PbSbOrCl and ekdemite. Z. Bl ixitec Pbl6(0,0H)16_xct 0rthorhombic B 5 83 25.47 5 69 Kristallogr-, I 03, 420430. Nadorited Pbsb02c1 I4/m a=3.90,c=12.29 Structure Reports (1947-1948) Vol. ll. Oosthoek, Utrecht. ( syntheti c ) Sundius, N. (1931) On the triclinic manganiferous pyroxenes. lz. Mineral., 16,4ll-429 and 488-518. aGiuseppetti beitto""g ccabrielson andTadini (tsz:), (1961), et al dsilte'n (1960), andt4elander (1941 ). Manuscript receiyed, September 19, 1979; acceptedfor publication, November 26, 1979.