Papagoite, a New Copper-Bearing Mineral from Ajo, Artzona*

THE AMERICAN MINERA]-OGIST, VOL. 45, MAY-JUNE, 1960

PAPAGOITE, A NEW COPPER-BEARING MINERAL FROM AJO, ARTZONA*

C. OssonNn llutrow, StanJord'(Iniaersi'ty, Stanford', California, .qNpANcBr-rN.q, C. Vr-rsrors, U. S. Geologi'colSuroey, Washington,D. C. AssrRAcr

thereof. to (100) was noted in thin sections but it was not evident in crystals or fragments Papagoiteismonoclinicprismatic,spacegroup Cm,C2,otC2fm,witha:12'9lA'b:ll'48' pattern is re- ,:+.05, all values +0.01 A; g:100'38'; aibic:1.124;l:0.408. A powder of the five corded and it has been indexed up to 2A-65o; the d-spacings and intensities (8)' strongest lines are: 2.874 i\ G0), 4.29 (9),2.204 (9),2.795 (8), and 3 '44 The mineral has a cerulean biue color in hand specimen and is distinctly pleochroic. : -a : 2Y : 78" dispersion faint' Biaxial, negative; a : 1.607, B : l'641, t l'67 2, 7 0'065; ; r)v;X:very pale glaucousgreen to colorless,Y: cendreblue, Z:Venice gteen;ZlYlK; to the Xnr:++" both in the acute angle,and Z:b'Y is very nearly normal "iXnd:35',

4 { CaCuAl[SiOr],(OH) ' I . in which The mineral has been named for the Indian tribe that once inhabited the region the mining center of Ajo, Arizona, is situated'

Occunnoncr The papagoite-bearingspecimens were found at Ajo, Arizona, in an isolatedpocket 150ft. below ground-levelat the 1750level in an areathat has now been entirely removed. The nearest high-grade sulfide ore now lies 50 ft. below and 1000ft. eastof the papagoitelocality'

and calcite, and minor quantities of apatite that is weakly dichroic,

* Publication authorized by the Director, U. S. Geological Survey' 599 C. O, IIUTTON AND A. C. VLISIDIS

I mm.

Frc. 1. veinlets of papagoite in an assemblageof clear quartz and dusty albite; the black areas are manganese and iron oxides and hydroxides. The small patch of fibrous material near the center of the drawing is ajoite. Ajo, Arizona. stumpy crystals of rutile, sphene, slightly metamict zircon, tiny well- formed, sharply pyramidal crystals of anatase,alunite, and patches of brown manganeseand iron hydroxides;rare tenorite may alsobe present in thesebrown areas.Sulfides were not detectedin the material examined. clearly the specimensare the product of metasomatismbut, sinceno rel- icts of the original unalteredmaterial remain, one is unable to say if the specimenshave beenderived from the monzonitelitself. The mineral describedherein has been named papagoite2after the rndian tribe that inhabited the areain which the active minins centerof Ajo is situated. Puysrcar- PnopBnrrBs In hand specimen, the color of papagoite is very close to Ridgway,s ceruleanblue (Ridgway's Plate 8,45. BG-B), and in thin section,or in crushed particles with a thickness of about 0.03-0.04 mm., a strong pleochroismis evident.The following optical data have beendetermined: a:1.607, +0.001,0:I.641, t:1.672,7-a:0.065; X:colorless to very 1 For comprehensive studies of the geology of Ajo, Arizona, in particular, and the region in general, the reader is referred to the work of J. Gilluly (1931 A, lg37 B, 1946). ' PAPAGOAIT (Royal Geographic Society (R.G.S. II) System); pepagoite (American usage). PAPAGOITE,A NEW COPPERMINERAL 601 pale greenish-blue(pale glaucousgreen, Ridgway's Plate 33, 39". B-G, f), Y:blue (cendreblue, Ridgway's Plate 8,43. G-8, b),Z:deep greenish blue (Venicegreen, Ridgway's Plate 7, 41. BB-G, b). Z>Y>X. 2V:78" *1o, and negative optic sign. Dispersion is exceedinglyfaint with r)v. The extinctionangie Xr\6:44o, or X/\a:35o, both in the acuteangle, whereas YAc:46o. Y to the perpendicularto (001) is ap- proximately36". Z:b (Fig. 2). If crystalsthat exhibit prominent developmentof the form [201] are orientedin mounting media with (201)parallel to the microslide,slightly

Frc. 2. Optical orientation of papagoite from Ajo, Arizona. The plane of the drawing is perpendicular to the b-crystallographic axis [:7]. off-centered optic normal interference figures are observed. The refractive index 7 and a value very closeto d. may be measuredwhen a crystal is oriented in this fashion, whereasfor crystals lying on the dominant face in the zone [0101,aiz., (001), the appropriate vibration directions havethe refractiveindices a':I.615 and'y: l.672.Thisis the mostusual aspectassumed by crystal fragments in immersion media if the appropriate face in the zone [010] has not been destroyedduring removal of crystals from matrix. If crystal fragments should lie on (401), then the refractive indices are equivalent to ? and a value almost equal to a. The mineral has a hardnessof about 5-5|, that is, it may be scratched by adularia but not by apatite, and the specificgravity at 19oC. of the analyzed material was determined to be 3.25 by centrifuging the powder in bromoform-diiodomethane mixtures.During separationof papagoite from the matrix the specific gravity of any one fraction did not vary from 3.25 by more than 0.005. A distinct cleavageparallel to (100) is evident, but this is to be seenonly in sectionsof papagoite that have 602 C. O. HUTTON AND A. C. VLISIDIS been carefully oriented and cut parallel to a plane perpendicular, or nearly so, to the vertical crystallographicaxis.

Cnvsrerr,ocRApHy Only partially complete crystals were available to the writers and these were found in occasional vugs in qvartz veinlets; none exceeded 0.75 mm. in length. Although they were detachedfrom the walls of the host with care no completeeuhedra were found. Crystals tend to be slightly elongatedparallel to the b-axis,the dominant zoneaxis, and somewhatflattened parallel to {001}. AII facesin the

Frc. 3. Typical crystals of papagoite from Ajo, Arizona. zone [010] are strongly striated parallel to the zone axis. Goniometric measurementsyielded data that lacked desirablepreciseness on account of oscillatory combination of faces,but more so becauseof the presence of satellites and accessoriesthat may depart as much as 4o from the orientationof the planeswhich support them (Fig. 3A, C). Only one general habit was found, and in most of the crystals observed c[001], g{a01}, and mt110} are dominant (Fig. 3C). Other facesin the zone [010]are dll}2l, elt}ll,f{201}, htt60ll,and a1100}.The dominanceof c{001} and d{1021, or sometimesfl2}ll, and a marked suppressionof o[100] Ieadsto crystals that are tabular in form (cf. Fig. 38). Facesof the form mlI10\ are, for the most part, devoid of satellitesand striations and consequentlythey yield good reflections.The satellitesare clearly PAPAGOITE, A NEW COPPER MINDRAL 603

Tnst,e 1. Irqrnnrecrnr. ANcr,rs ron Pep,l^corrn

Meas. angles No. of meas' made Calc. angles*

100n110 47"30', 47"50', 001n102 10' A 9050' 102n101 A 8'40', 101n201 13'30', 13044', 201n401 160 A 16'10' 401n601 8'30', 8"25', 601n100 22"30', 2 22"35', 110A110 84" 84"15', 110n001 83' q 82'55',

* Since the unit cell dimensions from e-ray data are considered to have an accuracy of This one part in 1,000, the calculated angles in this column are given to the nearest 5'- argument applies to the angles listed in Table 2 also. the result of crystal growth, sinceno indicationsof etch phenomenaare apparent. Pyramidal faces appear to be absent from the nine crystals that were availablefor study. Goniometric measurements,which are consideredto have an accuracy that is no better than *30', are given in Table 1, where thesedata may be comparedto the interfacial anglesthat have been derived by caicula- tion from cell dimensionsyielded by single-crystal n-ray work' The values listed for the measuredangles are, in eachcase, averages of severalmeas- urements. The data securedby goniometric measurementlead to an interaxial ratio of aib:c:1.109: 1:0.415with B: 100o30',compared to the data derived from fr-ray measurements' ai,z', a:b: c: l'124521:0'4085'

Tnnle 2. Sre.Nl.tnnANcr,n Tesre ton P'tpacotrr Monoclinicprismatic. a:bic:1.12+5i 1:0.4085;g:100'38'; poiQoiro:o.3632:0.4015:1; : rzipz: qz: 2.4906:0.9046 : | ; p : 79" 20' ; ps' : 0.3695, q6': 0.4085,ro' 0'1877'

6z Pz:B A

c 001 90"00' 10'40' 79"20', 90'00' 0"00' 79"20', o 100 90"00' 90"00' 000 90 00 7920 000 m l1O 42 l0 90 00 000 42 r0 825s 47 50 e l0l 90 00 29 lO 60 50 90 00 1830 60 50 47 ro J 2o1 90 00 42 50 47 r0 90 00 32 r0 g 401 90 00 59 00 3100 90 00 48 25 31 00 h 601 90 00 6725 2235 90 00 56 50 2235 d toz 90 00 2025 69 35 90 00 950 6935 604 C. O, HUTTON AND A. C. VLISIDIS

0:100'38'. On the basisof the latter, the standard angles,Iinear, axial, and polar ratios,etc., have beencalculated and presentedin Tabie 2.

X-n,c.y sruDy- considerable difficulty arose when attempts were made to orient crystal fragmentsfor single-crystalstudy becauseof the developmentof satellitesor accessorieson each crystal. Even fragments that measured about 0.1 mm. in diameter yielded r-ray difiraction patterns that one would expectto find for polycrystallinematerial. rn the simplestcase, it was possibleto orient the fragment so that straight, parailel layer Iines yielded by the host were dominant, but, at the same time, were con- siderably obscured by reflectionsdue to satellites whose orientations differedfrom that of the host by as much as 4o in some instances.This situation was most seriousfor rotations about the a and.baxes, since the reciprocalspacings perpendicular to thesedirections are relatively small, with the result that layer lines are crowded. After considerableexperi- mentation it was found that crystal fragments with diametersconsider- ably less than 0.1 mm. were necessaryif clean, single-crystalpatterns were to be secured,and this situation made handling and orientation difficult. Using Ni-filtered copper radiation, and a camera of 57.29mm. diameter, single-crystal rotation photographs were obtained for rotation about three axes,and weissenbergfilms for eachlayer were also obtained. Zero-layer photographs, calibrated with quartz, gave the following cell dimensions:a:12.91 A, a: 11.48, c:4.69, all values f 0.01 A; 0: 100o38'*6/.This leadsto the ratio a;b:c:1.1245:1 :0.40g5.A study of the weissenbergfilms indicates the following extinctions: hkr with hj-k odd; hencea C lattice. With the morphology of the crystals taken into account,this leads to three possiblespace-groups Cm, C2/m, or C2. No tests for centrosymmetryhave been made. The powder pattern for papagoite (Table 3) has been indexed up to approximately 20:65", on the basisof the cell dimensionsobtained by single-crystalstudy. Reflectionsat anglesgreater than20:65o tend to be weak and oflen are quite diffuse;furthermore, owing to numerouscoin- cidences,indexing of the high-angle reflectionsis unsatisfactory.

Cnpurcal CouposrrroN Crystal fragments of papagoite must be heated in a closedtube to a dull red heat before any indication of decompositionis observedlwhen this doesoccur the mineral breaksdown without decrepitationand water is evolved.A drab brown powder remains and since the temperatureof decompositionis high, fusion with the glassof the tube results. PAPAGOITD,, A NDIV COPPER MINERAL 605

Taslr 3. X-nev Pomnn Drlln,qcrroN Dara lon Pereconr, A;o, AnzoN,t Analyzed material; film No. 717. Cr*o (Ni filter), K.:1.5118 A. Cu-".a diameter:114.59 mm, cut-off at ca. 18.5 A. Spacingscorrected for film shrinkage. Simplified formula: 4{Ca, Cu, Al [SiOs]r(OH)3]. a:1291A, b:tt.+8, c:4.69,0:100'38'; Cm, C2fm, or C2.

d (meas.) il (ca1c.)2 d (calc.)z

7 6.33 6.36 200 <1 r.934 422 5.74 020 t.9295 222 7 4.61 4.61 001 6 t.9r3 060 9 4.29 4.28 T11 1.908 3s2 4.255 220 1.905 132 1 4.t2 4.11 20r 5 t.864 1.864 5r2 1 3.95 3.96 310 <1 I .846 1.848 tt1 7 3 .85 3.85 111 1.819 531 1 J.O/ J.O/ 130 1.800 601 3.59 02l 1.798 ,4) 8 3.44 3.M 201 1.797 o42 1 3.34 3.34 22I r.791 7r0 061 o 3 .30 3.30 3-11 r.767 -602 <1D J.l/ 3.17 400 |.726 2 2.95 2.95 221 1.720 402 2.945 T31 1.719 1.719 621 10 2.874 2.872 401 r.702 1.703 550 2.870 040 r.693 532 I 2.833 2.836 330 1.690 332 8 2.795 2.796 131 <1 1.680 641 2.780 311 1.669 442 2.777 420 7 l.oo/ 242 2 z.olo 2.616 240 1.652 622 L 2.565 2.570 42r 1.648 422 2.563 331 l2 1.638 730 2 2.477 2.479 510 \2 1.632 73r 3 z.+31 2.436 041 3B 1.587 800 1 2.409 2.413 401 ir.sor 203 I 4 2.368 2.367 511 1 I 2 352 241 [1.sse 712 2.307 202 1.554 512 2 .305 o02 1 I .545 1.546 I lJ Izn 2.299 2 297 112 1..)J/ 003 \se 2.292 2.293 331 <1 1.535 821 2.225 421 1.529 820 9 2.204 2.204 241 1.525 641 2.159 It2 1.524 1.524 313

1 Intensities were estimated visually. 2 dr,*rcalculated for all reflections observed on Weissenbere films down to 1.428 A. B: Broad line. D: Difiuse line. 606 C O. IIUTTON AND A. C. VLISIDIS

Tasr-n 3 (Continued)

I d(meas)ld(calc.)2 Ir I 2.140 2.141 222 <1 |.498 1.496 403 2.139 o22 1 1.483 1.484 o23 2.130 2.130 MO r.479 642 2.116 530,600 1.4/J 1.475 442 2.073 2.073 601 |.472 o62 2.052 2.O53 402 1.468 73r 2.048 202 1.455 732 2.045 DJI 1.451 532 2.034 2.O35 511 1.4+7 42s 2.030 441 1.445 IJJ r.999 r.999 732 1.437 802 1 983 1.984 620 1.435 080,203 I .950 62r (r.+ss ffi2 ) I 1r.428 DJJ

d (meas.)

<1 1.416 1.162 <1 1.403 1.146 z 1.393 I.IJJ {r 1.376 1.1195 \2 1.372 1.102 2 1.356 1.084 1D | 323 1.063 1 1.293 I .0495 2 1.284 1.o23 1 |.275 1.013 <1 1.240 .972 z 1.229 .959 2D 1.219 .9525

Fineiy crushedpapagoite dissolves very slowly in boiling concentrated HCl, and alter 24 hours treatment with a hot constant-boiling mixture of HCl, only partial solutionhas occurredwith concomitantseparation of a flocculent form of silica. Severalcrystals were immersedin ammonium hydroxide (sp. gr. ap- prox. 0.89 at 21" C.) in a tube, and the appearanceof the mineral par- PAPAGOITE,A NEW COPPERMINERAL 607 ticles was observedfrom time to time. Absolutely no change was ob- servedat the end of 72 hours. The same crystals were then placed in a tube and about 20 ml. of liquid ammonia added; the tube was then immersedin a mixture of acetoneand dry ice in a Dewar flask. After 24 hours someliquid ammonia was stili presentbut the tube was cakedwith ammonium carbonatecrystals. On recovery, the color of the papagoite crystals was found to be completelyunchanged. Accordingly, in neither experimenthad a significantamount of ammonia-exchangetaken place L0.42-gm. sampleof pure papagoitewas heatedto temperaturesup to 800oC., and at intervalsof approximately50'-75o C., the weight of water evolved was recorded. Virtually no water was given ofi until a tempera- ture of 500oC. was attained. Between that temperatureand 750" C. al- mosl all of the water was freed from the mineral. No indication of any discontinuity wasf ound in the dehydration curve (Fig' 4). For the determination of the extent of physical changesin papagoite during heat-treatment, x-ray powder patterns were obtained for samples

UJ F 4, =

F- z U o E4 U o-

300 400 500 600

OEGREES CENTIGRADE

Frc.4. Dehydration curve for papagoite' Temperatures of 700'and 800' C' are +50" C' 608 C. O. HUTTON AND A. C. VLISIDIS

Tesrr 4. ANlrvsrs ol Pepaconn altl Calcur,arrn Cnrr, CoNrBNrs Analyst: Angelina C. Vlisidis

Wt. per cent Ionic radii Cations

SiOz 33.60 7.48 I .+6 (Ht .30 8.00 .22 AlzOs 15.78 0.50 A1 4.14 a oeJ Mgo 0.09 0.65 Mg .03 .03| 4.00 TiOz 0.26 0.68 Ti .05 .Osl FeO 0.27 0.7s Fe .05 .0sI MnO 0.10 0.80 Mn .02 .o2l4.02 CuO 23.53 0.83 Cu 3.95 3.esl CaO r7.02 0.99 Ca 4.06 4.06 4.06 ilro s1 1.20 HrO+ 9.01 13.381 I 12.r812.18 HrO- 0.04

99.70

Si: 7.48 ) Al, Mg, Ti, Fe, Mn, Cu, Ca: 12.30 Oxygen: 36.07 Hydrogen: 13.38 Cell weight: 2220.25x10_24gms. Factor: 1337.26

heatedin air at temperaturesof 460o and.720oc. The material heatedat the lower temperatureyielded a pattern that is identicarwith that of the untreated mineral. On the other hand, papagoiteheated at 720" C. for 2| hours yields a complexpowder pattern in which lines due to tenorite are dominant, but many additional, but lessintense lines, not due to the copper oxide' are present. The strongestlines of these correspondin a general way to those reported for the artificial orthorhombic silicate of

present entirely as hydroxyl and not as molecular water. A completechemical analysis of papagoiteis reported in Table 4. A 2- gm. sample for the analytical work was obtained by first handpicking a crude concentrateof papagoitefrom a specimenthat had beencrushed to passthrough a 16-meshscreen (Tyler series).This concentratewas then PAPAGOITE,A NEW COPPERMINERAL 609 hand-crushedto pass through bolting silk of approximately 0.06 mm. mesh, and the resulting material was repeatedly centrifuged until a pure fraction wassecured. The cell contentshave beencalculated from the weight per cent of each oxide on the basisof the relationshipP*/l00MXW/1.6603, where the oxide is expressedas P^O,, M:molecular weight of the oxide, and W : cellweight. It will be noted that the numbersof Al, Cu, and Ca ions are extremely close to the figure of 4 in each case,oxygen to 36, but the figures for Si and H are irrational. In attempting to write a formula it should be remembered that dehydration data and failure to prepare ammonia-exchangeproducts suggestvery strongly that water molecules are absent, and instead, hydrogen is present as hydroxyl. One of the difficulties that arises,however, is the means of accommodating all of the hydrogen ions. If all of the hydrogen is present as (OH) ions, the Si-O ratio that appearsto be most probableis 1:3, that is, [SiO3]".The Si-O arrangementfound in the phyllosilicates,uiz., [SiaOro],appears to be a possiblelinkage if large amounts of the Al are consideredto be in four- coordinated positions. Under these circumstances,a rather unsatisfactory formula may be developedbut it should be noted that the physical properties of the mineral do not seemto support the belief that papagoite has a sheetstructure; caution must be observed,however, in this re- spect,since datolite containsinfinite sheets(Ito and Mori, 1953,p.30; Christ, 1959, p. 176), even though the external physical propertiesof that mineral do not suggestit. On the basisof an Si-O ratio of 1:3 one may write a simple formula, except that one finds a deficiency of Si and an overabundance of H ions. This leads one to envisagethe different ways in which hydrogen' unac- companiedby extra oxygen, may be accommodatedin silicates.These possibilitiesmay be summarizedas follows:

1. Replacement of oxygens in the Si-O tetrahedra bV (OH) so that (SiOrOH) groups are formed as in the mineral afwillite, Car(SiOsOH)z'2H:O (Megaw, 1952,p.477- 49r). 2. [OH]4 may replace [SiOr] as in hydrogrossular (Hutton, 1943), zircon, thorogummite (Frondel, 1953), vis6ite (McConnell, 1952), etc., and it may partially replace [SiOa] groups that link together to form the SimOararrangement in amphiboles (Zussman, 1955, p. 301-308; Nicholls and Zussman, 1955, p. 717-722; Hutton' 1956, p- 231- 232).

Now, so far as papagoite is concerned,replacement of some of the oxygensof the Si-O tetrahedrain the [SiOa]groups by [OH]' in a manner similar to that which has been shown to be the casefor afwillite, is unsatisfactory since there are insufficient cations of suitable ionic radius to bring the Z group to the supposedfigure of 8, and, at the same time, pro- 610 C. O. HUTTON AND A. C. VLISIDIS

vide a suitableelectrostatic balance elsewhere in the arrangement.With the secondalternative arrangement,however, a good measureof agree- ment is obtained if 1.20hydrogens and0.22 aluminum are consideredto replace silicon in order to bring the Z group to the figure of 8; at the same time this leaves approximately 12 hydrogens to form hydroxyl and 24 oxygensfor the ISiOB]"groups. Upon this understanding,the suggested distribution of ions is given in Table 4. On the basisof the figuresin the last two columnsin Table 4 the em- pirical cell contentsmay be expressedas follows: Caas6(CuB. ss,Mno. o:, F." or)(AL*, MgoqflAlga,ag, sAlo.rt Ozr(OH)rz. rs " 4.02 4.00 8.00 The formula may be expressedmore generallyas follows:

CarCuEAlr{ [Si, A1]8-"Or4-4"(OH)* ] (OH) tr, or under the assumptionthat the silicon positionsmay be, under other circumstances,fully occupiedby silicon, the formula for papagoitemay be written as follows: 4 {CaCuAlISiOr]r(OrD, ]. AcrNowr,BoGMENTS

The authors wish to thank Mr. Scott J. Williams of Scottsdale, Arizona, for the material that formed the basis of this study, and to acknowledge his perspicacity in recognizing that the mineral was of an unusualcharacter. Furthermore, we are indebtedfor helpful discussionof severalpoints, to Dr. Waldemar T. Schaller,Dr. Michael Fleischer,and ProfessorAdolf Pabst, and to Dr. Frederick G. Tickell for assistancein the laboratory. Rprnnrxcns Cnnrsr, C. L. (1959), Garrelsite and the datolite structure group: Am. Mineratr.,44, 176-

Davrs, G. L., axo Turrr,n, O. F. (1952), Two new crystalline phasesof the anorthite composition, CaO-ALOr2SiO2: Am. Jour. Sci., Bowen Volume, 107-114. FnoNror,, C. (1953), Hydroxyl substitution in thorite and zircon: Am. Mineral.,38, 1007- 1018. Grtr.ur.v, J. (1937A), Geology and ore deposits of the Ajo Quadrangle, Lrizona: Ariz. Bw. Mi.nes, Geol.Ser. No.9, Bull. No. l4l, 1-83. -- (19378), Physiography of the Ajo region, Arizona: Geol,. Soc. America Bull.., 48, 323-348. --- (1946), The Ajo mining district, Arizona: Lt. S. GeoL Suraey, ProJ. Paper 209, l- 1121'and, supplement. Huttow, C. O. (1943), Hydrogrossular, a new mineral of the garnet-hydrogarnet series: Royal Soc Neu Zealand., Trans., 73, 3, 17+ 180. -- (1956), The composition of an actinolite: Acta Cryst.,9, 231-232. PAPAGOITE, A NEW COPPER MINERAL 6II

Iro, T., ero Monr, H. (1953),The crystalstructure of datolite:Acta Cryst.,6,24-32' McColwnr,r,, D. (1952), Vis6ite, a zeolite with the analcime structure and containing linked SiOr,POr, and H*Oagroups: Am- Mineral., 37, 609417. Mncaw, HBr.amD. (1952),The structureof afwillite,Cas(SiOaOH)z'2HzO: Acta Crysl',5, 477491.. Nrcuor-rs, G. D., .Lr.roZussMax, J. (1955),The structural formula of a hydrous amphibole: M i.neratr. M ag., 30, 23O,7 17 -7 22. Rrocwev, R. (1912),Color standardsand color nomenclature,R' Ridgway, Washington, D.C. Scnnlr-nn, W. T., eNo Vrrsrnrs, ANcrr,rl{e C. (1958),Ajoite, a new hydrous alurninum coppersilicate: Am. Minerd.,43, 1107-ltll. Zussur.N,J. (1955),The crystalstructure of actinolite:Acta Cryst'.,8'301-308. Monuscri,ptreceioeil August 10, 1959.