Anzerican Mineralogist, Volume 59, pages 1157-1159,1974 Yedlinite,a NewMineral from the MammothMine, Tiger,Arizona W. JoHNMcLnaN. Departmentof Geosciences,Uniuersity ol Arizona, Tucson,Arizona85721 Rrcnl,no A. BroeRux, 1242 WestPelaar, Tucson, Arizona 85705 aNoRrcnlno W. TnorrlssrN 2I 38 CaminoEl Ganado.Tucson. Arizona I 57I I Abstract Yedlinite is a new hydrated oxychloride of lead and chromium found associated with diaboleite, quartz, wulfenite, dioptase, phosgenite, and wherryite on specimens from the Mammoth Mine, Tiger, Arizona. Yedlinite occurs as prismatic crystals up to one millimeter long which are red-violet, transparent to translucent and somewhat sectile, with white streak, Mohs'hardness of about 2 l/2, and observeddensity of 5.85 g/cc. Crystals show rhombohedral symmetry with forms {11t0}, {1i01}, {0001}, {1010} and {2021} in order of decreasing prominence.Crystals are occasionallydoubly terminated and exhibit distinct {1120} cleavage. The morphological axial ratio is c/a - 0.763(2). Yedlinite is optically uniaxial negative and dichroicwitho = 2.125 (pale cobaltblue) and e = 2.059 (lavender): X-ray diffraction shows space group R3 or R3 (R3 is indicated by morphology and confirmed by structure determina- tion), a - 12.868(2) A, c - 9.821(2) (hexagonal axes), cfa - 0.7632(3). The most intense powder difiraction lines in order d (I) (hexagonal hkil) are: 2.952 ]0O 3141,2.622 6E 3142 and,1342.4.506 65 01i2. 6.44 32 1120 and,2.473 27 32-51and 0333. Electron probe analysis combined with structural information yields the chemical formula PbuCLCr&Y, with X - O or (OH) and Y - H,O or (O,OH). The hexagonalunit cell content,Z - 3, and the calculated density is 5.80 g/cc. The name honors Mr. Neal Yedlin. fntroduction Occurrence The mineral herein described was first noted in Yedlinite is known only from the Tiger locality 1967 by Mr. Neal Yedlin of New Haven, Con- and is found sparinglyon a few specimens;perhaps necticut, a well-known amateur mineralogist, col- the most notableis NMNH R-8171. It is associated lertor, lecturer, and writer on micromounting in with the most complex paragenesisyet observedin mineralogy, in whose honor it has been named. Mr. MammothMine material.Minute, doubly-terminated Yedlin first observed the specieson material obtained qvartz crystals, which replaced primary galena, from Schortmann's Minerals, Easthampton, Massa- formed a framework for depositionof diaboleite. chusetts, and deposited several fragments in the This was later relaced by phosgeniteand rarely National Museum of Natural History. Other speci- matlockite, and altered to wherryite. Yedlinite crys- mens were later noted in the NMNH collection and tals are commonly found growing upon and partly were included in an ongoing study by one of us surroundedby diaboleiteor in intimatecontact with (RAB) of the Mammoth Mine suite. All specimens phosgenite.Wulfenite, dioptase, cerussite, mimetite, seem to date from collections made at the mine in willemite, hemimorphite,fluorite, and quartz were 1940-41 (Palache, l94I). About 150 crystals are later superimposed.The latter assemblageis usually presently known. The name and specieshave been observedseparately on other specimensfrom the approved by the IMA Commission on New Minerals mine. Yedlinite is rarely observedperched on diop- and Mineral Names. taseand amongthe fluorite and drusy quartz.Crys- tt57 I 158 MCLEAN, BIDEAUX, AND THOMSSEN streakis white. The Mohs' scalehardness is about two and one half, and the mineral is generally not brittle and somewhatsectile. The densities,deter- mined by weighing two single crystals and calculat- ing their volumesfrom microscopicmeasurements, were 5.88 g/cc for a 2l p,gcrystal and 5.81 for a 45 y,gcrystal;the observeddensity is thus about5.85 g/cc. Crystal morphology suggestspoint group 3 2/m andis dominatedby the secondorder hexagonalprism { I 120}'andthe relativelyflat rhombohedron{ 1101 }. Usually also presentare the basalpinacoid {0001}, the first order prism {1010}, and sometimesthe 2to izo rhombohedron{2021}. The crystalsare occasionally doubly terminated.The goniometricaxial ratio using hexagonalaxes is c/a = 0.763 r-_0.002 basedon measurementof.1.7 faces of the {1101} form ( p = 41.4') and sevenfaces of the {202L} form (p = 60.6") on four crystals.An idealizedcrystal draw- ing is shownin Figure 1. Distinctprismatic cleavage, U,l20j, is detectable. Optically, yedlinite is rrniaxial negativewith , = 2.125 and e = 2.059 (r: 570 nm). Crystalsare Tesre l. lndexed Powder Pattern for Yedlinite* Frc, l. Axonometric projection of an idealized crystal of rrel. dobs. d"tL". hkL lr"t. dob". d".1". hk] yedlinite. The c axis is vertical, and ae is to the right. Faces 7,315 7.368 tol 4 1.530 r.527 62r of the two most important forms are indexed with the 5. tr40 5.\3u il.o r.5oa r".!98 305,036 superfluous i index omitted. l_I !. 861 b.815 o2r 1,!?5 1.lr?! 622,262 !.505 l+.L9l+ 012 ].161 r.u59 226,226 R71 111 lr1 I 1.!39 1.!36 z\S 3.879 " 1I 3.719 3.715 3oo t. !02 15, 1I 3.287 3.27\ 003 6 1.399 1.39? 15!,61E 3,217 220 r.392 tals of other mineralsare never observedto be im- 12 3.2A6 3.19? r22 t.3rr0 \oa planted yedlinite. 1.00 2,912 2.9\8 :r1 r.3br l.:ig :l: on A little earthy hematite is 6 2.683 2.68a lol f, JJO >54 r.290 633 occasionallypresent. 68 2.622 2.616 :rz, r32 b L'ze> 2.\7)1 32r r,28r- 169, 6v Chromium, essentialto yedlinite, is apparently 27 2,473 2.\16 033 r..238 7,237 53' 11 2,\32 1110,1110 t,2r5 372 2.\16 I r'zL) an extremelyminor elementin the Mammoth Mine 2.297 2,295 223,223 1,,215 25j 11 2.126 2,r2r zLu I 1.207 r.206 526, 526 ores. Exceptionalfornacite crystals are rarely locally , r.913 r.gj2 \r3, r\3 r.160 191, 551 r.936 dt-a, \22 r.r59 1.r58 093 abundant.Crocoite has been reported,but cannot t2 L,y5) 1.934 0r5 r.v6 7!0 r.922 3rl r,136 1ez, V2 confirmed 5 r!r)r be by our observations.Sparsely occurring 1. 8t7 600 1'131+!51 1,Lo? 326 yellow-greencerussite and wherryite, yellow lead- I 2 r r^r 1.8!2 1104 1.103 832 ll !31 1. o9o trf3 hillite. and brilliant red wulfenite mav owe their r. 80\ I. 801+ v>L 1 L' 1. o8z J-67 10 r.?BL 2ro 1.030 color to this element. l-.?80 zt9 r ' urr 930 ll r.?r5 3\2, \32 L. o3o 8\e 1,.6r, 5rI,16r .988 9a6 i..605 162 ^ar .983 933 6 ''eL Physical,Crystal and Optical Properties r.509 1.505 045 ,980 835 .978 1.0.10 Crystals yedlinite t\ 1.5?o 1 .6a <t? ,<? ,q? a^L .891 l-88 of are transparentto translucent 'u'r .892 L.10.o hexagonalprisms up to about one millimeter in . Taken Ln a 714.6 M Debge-schettet careta with CuKq radiatlon' length and are generallyabout 0.4 as thick as they A pseudo-Epwdet pattert taken with a GandoLfi-tgPe devlce con' tained an addltlohal, 33 lines' lndlcating extensl've structure are long. The color is red-violet,and may vary both danaEe in ptoducing a Powder. in hue and intensity within a single crystal. The The su:perfl,uous i jndex ls onitted fton all hkll teffectlan ln'lices' YEDLINITE, A NEW MINERAL I 159 moderately dichroic with , pale cobalt blue and e Trtr-B 2. Chemical Analvsis of Yedlinite lavenderand more strongly colored.' Element Probe Pb 2H2o Pb.ct.cr (0H) (o, oH) 6CISCro 6. 6 2 X-Ray Diffraction Study Mn Yedlinite Pb 79.4 75,8 wt, "A 75.7vt,7. single crystals were examined by the Cr 3.8 3,2 3.2 oscillation and Weissenbergtechniques using CuKa c1 7.5 13.0 13.0 o 8,6* 7.8 7.8 (I = 1.5418A) radiation.Systematic absences on tt .2 I Weissenbergfilms coupledwith diffraction symmetry L00.0 100.0 100.0 3 showedthe spacegroup to be either R3 or R3. x By dlfference. The morphological3 axis indicated the spacegroup to be R3 and this was verified by the crystal struc- ture determination(Wood, Mclean, and Laughon, volatile elernentswould be erroneously high. The 1974). Measurementsof 20 for 29 Weissenbergre- chemicalformula derived from the microprobe anal- flections were used to refine the unit cell dimen- ysis was therefore treated only as an approximation. sions by the least squaresmethod yielding c : As there is insufficient material to use other com- 12.868(2)A and c : 9.82I(2) for the hexagonal mon analyticalmethods, it was necessaryto deter- cell (a = 8.119A anda = 104.84ofor the rhombo- mine the detailsof the compositionby determining hedral cell). The X-ray axial ratio is c/a : the crystal structure.The crystal structureanalysis 0.7632(3). (Wood et al, 1.974)shows the hexagonalunit cell A powder diffraction pattern was prepared using to contain 3[PboCloCrOoOz]with hydrogen unde- CuKc radiation and a 1L4.6 mm Debye-Scherrer termined.Depending on the valenceof Cr, 4 or 7 camera.Relative intensities were visuallyestimated, hydrogens are required for neutrality. Many com- and the lines were indexed (Table 1) using the positions are possible, but the most likely are hexagonalunit cell parametersand intensitiescal- PboCloCrOe'zH2O, PboCloCr(O,OH)6(O,OH)2,and culatedfrom thecry/stal structure. PboCleCr(OH)6(O,OH)2.These compositionsre- sult in a calculziteddensity of 5.80 which compares ChemicalComposition well with the measureddensity of 5.85 g/cc.