.I'IIE AMERICAN MINERALOGIST, VOL. 45, NOVEMBER_DECEMBER, 1960 STUDIES OF THE MANGANESE OXIDES. IV. TODOROKITE* J. A. Srnlczrr,t Anrnun HonnN,{ M,c.rcorMRoss,$ aNl Cuenrorrn M. Wansuaw, Il t/. S. GeologicalSurz:ey, Washington,D. C. ABsrRAcr Todorokite is a very _ abundant manganese oxide minerar in many deposits in cuba and has been noted from other localities. Six new analyses are givenl they lead to the approxi- mate formula (Na, Ca, K, Mn+2)(Mn+4, Mn+2, Mg)oOrg.3HeO. Blectron diffraction data show the mineral to be orthorhombic, or monoclinic with B near 90". The r-ray powder pattern is indexed on a cell with o:0.75A, b:2.g4sA, c:9.59A, 0:90". A difierential thermal analysis curve is given. INtnoouctrou From 1940to 1945,the u. s. Georogicalsurvey made a study of the manganesedeposits of cuba and especially those in oriente province. Severalpreliminary reports were published and the results were sum- The present paper deals with a manganeseoxide mineral, whose *-ray pattern was recognizedas being distinctive in r94r and which was desig- nated for someyears as,,Mineral T.,, X-ray studiesby J.M.Axelrod from 1946to 1948showed that this mineral was an abundant constituent of the oresat many localitiesin oriente province, but that it was so inter- grown with other mineralsthat the preparation of samplespure enough to warrant chemical analysis was extremery difficult. The best five sam- ples were finally selectedand their analysiswas completedin 1952.At that time, it was learned that Arthur rroren, who had made a field study of the manganeseores of the charco Redondo-T aratana district in 1951- 1952, had also identified the same material by *-ray study at Harvard * Publication authorized by the Director, U. S. GeologicalSurvey. t Present address-Union Carbide Ore Company, 30 East 42nd Street, New york 17, New York. Present { address-Universal Atlas Cement, 100 park Avenue, New york 17, New York. $ U. S. Geol Survey, Washington, D. C. ll Present address-Pennsylvania state university, university park, pennsylvania. 1174 TODOROKITE 1175 now. OccunnBNcB auo OnrcrN PnovtNce' Cula Tasr,B 1' OccuRRENcEs or Tononorttn rN OmnNrn - Reference Simons and Straczek' Mine Name of workings, shafts, or pits 1958 (Pages) 158-161 Boston mine 167-170 Quinto mine K-6, Charco Redondo Socias,Marinez, Unitoria, K-l, Gutierrez BateY, No. 1, KX 185-191 t92-194 Lucia mine 195-198 Taratana mine Canada, Lego 202-204 Guanaba mine 213 Sorpresa mine 213-215 Manacas District 220 Fortuna mine 226-227 New York mine 235-237 Yeya mine 238-240 Abundancia mine No' 3, Ponupo mine W., Center, and E. Sultana, 2431256 Juanita 26+-268 Ponupo de Manacal 1176 T. A. STRACZEK,A. HOREN,M. ROSSAND C. 1,[. WARSHAW rn addition, todorokite has beenidentified by *-ray study in the labo- ratories of the u. S. GeologicalSurvey as a constituent of oresfrom the Embreeville mine, Embreeville,Tennesseel the Lucifer mine, Baja Cali_ fornia, Mexico; the Nsuta mine, Ghana, Africa; and the Taxud area, Philippines, also as a constitutent of incrustarionsfrom Bikini Atoil and of a deep-sea pacific, nodule from the from near CadizDry Lake, Cali_ fornia, and as a coatingon colemanitefrom Furnacecreek, Death vailey, California. The manganese oresat the cuban localitiesare interbeddedwith vol- canic tuff, now largely altered to montmorillonite clays, and with jasper (bayate), and limestone.At charco Redondo the "delatorreite,,is com- monly the matrix for limestoneand tufi and in part replacesthem. rt has commonly crystallizedaround kernelsof tuff. The bayate occursin lenses ranging in thicknessfrom an inch or two to as much as a foot. rt consists of rounded quartz spheruritesin a ferruginous matrix; the spherulites range in sizefrom a micron to severaltenths of a millimeter and com- monly show growth banding with silica alternating with layers of hy_ drous (?) iron oxides.The contact betweenthe bayate u.rd ihe massive todorokite is usually, but not arways sharp, and there was no definite evi- dence of either replacingthe other. Both were, however,cut by crystar- Iine quartz, commonly amethystine, which lines vugs and contains shreds of bayate and inclusions of manganite or pyrolusite. The last mineral formed was rhombohedral calcite, which occurs in veins and perched on the vuggy quafiz. The todorokite has been arterednear the surfaceand along faurts or fissuresto pyrolusite,and perhapsto mangantte. The origin of thesedeposits is discussedat somelength by simons and straczek (1958, p. 103-110), r,vhoconclude that the.orr... of th. -u.rgu- nese was probably hot springs. Horen believesthe deposits to be of marine sedimentary origin. rn contrast, the type todorokite from the Todoroki mine in Hokkaido, Japan,was believedby yoshimura (1934)to have beenformed by late-stagehydrothermar solutions artering inesite. Pnvsrcnr PnopBnrrps Todorokite from Cuba commonly occursas columnar aggregates,but is also found as fine fibers and as irregular masses.The cororand streak are brownish-black to dark brown; comparison by J. J. Fahey with Ridgway's color Standards of the anaryzed,samplesnos. 1-4 showed two matching dusky purplish gray and two matching sooty black. The ap_ parent hardnessis low, the materiar breaking into fibers; the true hard- nessis not known. Specificgravity measurementsby Horen of six sam- pleson the Berman balancegave an averageof 3.49;iorr. py.rro*eter de_ TODOROKITE II77 Ttrln 2. Axatvsns or "DrLATonRErrE" r'RoMCuse eNo Tooonortte lnou Tepar.l MnOz 72.37 72.t5 68.46 71.61 67.86 67.19 65.59 MnO 10.04 8.87 10.70 10.16 11.24 14.56 1237 CaO 2.57 1.52 2.13 2.66 5.51 2.03 3.28 SrO 0.60 0.24 0.13 0.53 0.92 BaO I . (r.) 0 20 0.40 0.18 0.54 0.14 2.05 NazO I .30 1.23 1.44 0.85 1.45 1.34 0.21 KrO 0.24 0.48 0.75 1.48 0.06 0.43 0.54 Mgo 1.04 3.51 3.22 1.58 0.88 3.13 1.01 CoO 0 .02 0. 18 0.23 CUO tr tr 0.44 tr 0.02 Alzo3 0.46 0.14 0.19 0.12 0.25 0.28 FezOs 0.06 0.06 0.07 0.06 0.18 o.20 SiOz 0.95 o.24 0.41 0.64 0.64 0.14 1.73" (rc.sg H:O- 1s.so ((Ito.at I o.os I s.+t lrso HrO+ t It rl {ro.oo | 9.72 Others 0: 7Cb 99.48 99.27 99.51 98.90 99.02 99.88 99.24 Active O 13.31" 13.25" 72.60" 73.12c 12.49" 12.o7 G 3.82 3.66 3.68 3.78 J. O/ a Includes SiOr 0.45, insol. 1.28/6. b Inciudes P2AbO.42,SO3 0.28, COz tr., TiO: tr. c Average of 2 determinations. Analyses 1-5 by C. M. Warshaw; SrO in CaO by W. W. Brannock and E. A. Nygaard with flame photometerl SrO in BaO by K. J. Murata and R. S. Harner spectrographically; alkalies by W. W. Brannock with flame photometer; FezO:colorimetricaily by S. M. Berth- old; cobalt by L. E. Reichen polarographically. Ana'lysis 6 by F A. Gonyer, Harvard Uni- versity;analysis No. 7 from Yoshimura (1934) Sample d.escr'iptions Nos. 1-5. Collectedby J. A. Straczek; No 1 from Quinto, shown by x-ray study to con- tain a trace of pyrolusite; No. 2 from Tarantana; No. 3 from Charco Redondo, contains a trace of calcite; No. 4 from Guanaba, contains a small amount of cryptomelane; No. 5 from Ponupol the :r-ray pattern shows some weak unidentified lines; No. 6 collected by Arthur Horen from Charco Redondo, Batey No 1 shaft. terminationsby Fahey and one by Yoshimura (Table 2) gave3.66-3.82; the higher vaiuesby pycnometerare to be expectedfor such fibrous ma- terial. CuBlrrsrnv Analyses of six samplesfrom Cuba are given in Table 2 along with the analysis of todorokite from Japan (no. 7). Spectrographicanalysis of Nos. 1-5 by K.J. Murata showedthe following: IT78 J. A. STRACZDK, A. HOREN,.41. ROSSAND C. M. WARSHAW Mo-.0X in samples1,2, and4, 0.00X in 3 and 5 V and B-.OX in samplesI and 5, .00X in 2 and 3 Ni-.OX in samples2,3, and 5, .00X in 4, .000Xin 1 Cu -{.X in samples3, .0X in 5, .00X in 4, .000Xin I and 2 Co--{.X in samples3, .0X in 2, .00X in 1, 4, and 5 Ti-.00X in samplesl, 2, and 5' .000X in 3 and 4 Not found-Ag, As, Au, Be, Bi, Cd, Cr, Ga, Ge,In, La, Li, Nb, P, Pb, Pt, Re, Sb,Sc, Sn, T1,W, Y, ZN. Analyses 1-7 (Table 2) were recalculated' neglecting SiOz, AlzOs, Fe2O3,P2O5, and SOe;it is possible that these are not actually impurities. For analysis 7,HrO+ was taken' for the others total HzO' From the unit cell dimensions obtained by Ross, formulas with O:11 or O:12 (not in- cluding H2O) seemed possible. The results are given in Tables 3 and 4. Tesl-n 3. Ax,q,r,vsns ol Tolono<rtr Rrce'lcur,alro ForO:11.0 >X Mol. Mgo >Y +Y HzO wt. 1 0.33 0.24 003 0.60 4.78 0.81 015 534 5.94 2.81 563 2 o17 0.23 005 0.4s 4.74 0.71 0.50 5.9s 6.40 3.36 564 3 o.25 o.27 009 0.61 4.59 0.88 051 5.98 6.59 356 576 4 0.31 0.16 0.18 0.65 4.74 0.82 0.23 q70 6.44 2.88 564 0.64 0.27 0 .07 098 4.s6 0.93 013 562 6.60 3.00 J/O o 0.22 o.25 0.05 0.52 4.49 r.t9 0.47 615 6.67 3.44 s79 7 0.44 0.04 0.08 0.55 4.64 r.o7 0.15 5.86 6.+7 3.32 583 ForO: 12.0 1 o.37 026 0.03 0.66 5.22 0.89 0.16 6.27 693 3.06 6t4 2 0.19 0 2.5 006 050 5.17 0.78 0.54 6.49 699 .t o/ 615 3 0.27 030 0.10 0.67 5.01 0.96 0.57 6.54 721 388 629 i 0.34 0.17 o20 071 J.I/ 0.90 0.25 o.