American Mineralogist, Volume 69, pages 465471, 19E4

Sadanagaiteand magnesio.sadanagaite,new silica-poor membersof calcic from Japan

Hrppnxo Sntrraezerr Geological Institute, Faculty of Science University of Tolcyo, Hongo, Tolcyo l13, Japan

Mrcnrerr Buuxor Department of Mineralogy, The University Museum University of Tolcyo, Hongo, Tolcyo 113, Japan

nxo Tonnu Ozewe Mineralogical Institute, Faculty of Science University of Tolcyo, Hongo, Tolcyo ll3, Japan

Abstract

Sadanagaite,(K,Na)CazGe2*,Mg,Al,Fe3*,Ti)r[(Si,AlhO22(OH)2] where Fe2* = Mg, Al = Fe3* and Si < 5.5, and its Mg-rich analogue,magnesio-sadanagaite Fe2+ < Mg, are extremely SiO2-poor new amphiboles, which require the compositional extension of the edenite-pargasiteseries, and amending of the classification and nomenclature of amphi- boles (Leake, 1978). Theseare monoclinic,C2, Cm or Cllm; a = 9.922(10),b : 1E.03(2),c : 5.352(9)4,B: 105.30(10f,Z = 2 for sadanagaitewith Si - 5.0, and a : 9.964(2),D : 18.008(3),c : 5.354(2)4,B = 105.55(2)",2= 2 for magnesio-sadanagaitewith Si:5.0. The strongest lines in the X-ray powder pattern for magnesio-sadanagaiteare: 8.48(80)(ll0), 3.39(40Xl3l), 3.28(100X240),3.15(70)(3r0), 2.951(50X22r),2.823(30)(330), 2.766(45)(33r), 2.707(60Xl5l),2.594(35X061),2.162(55)(261),1.654(30X461), thesebeing similar to thoseof X-ray powder patterns of SiO2-poorcalcic , especially . Both specieshave very similar physical properties, and are dark brown to black with a vitreousluster. very light brown. {110}, perfect. H (Mohs) : 6. Density (calc.) 3.30 g/cm3 for sadanagaite and 3.27 g/cm3 for magnesio-sadanagaite.Optically biaxial positive with2V = 80-X)" (meas.), 86" (calc.) for sadanagaite,and with2V close to 90o(meas,), 88'(calc.) for magnesio-sadanagaite.Refractive indices: a = 1.673(2),F = 1.684(2),y-1.697(2);c:Z=28'(sadanagaite),anda=1.674(2),8--1.686(2),y= 1.699(2);c:Z : 26"(magnesio-sadanagaite). Pleochroism strong with X' = pale brown to Z' - greenish brown (sadanagaite)and with X' = colorless to Z' = brownish yellow (magnesio-sadanagaite). The minerals are found in two separate localities, Yuge and Myojin Islands, Japan, where they occur in Al-, Ti- and Fe-rich skarns in recrystallized limestone beds, forming bands with vesuvianite, -hercynite, sphene, ilmenite and apatite in the former locality, and forming small lenses with titaniferous fassaite, vesuvianite, spinel-hercynite, sphene,ilmenite, magnetite,apatite and perovskite in the latter. Among them the peculiar composition of titaniferous fassaite is discussed with special reference to its extremely SiO2-poor, Al2O3- and TiO2-rich composition. The names are for Professor Ryoichi Sadanaga,Mineralogical Institute, University of Tokyo, in recognition of his outstanding contributions to the fields of mineralogy and crystallography.

I Presentaddress: Geological Department, Geological Survey ofJapan, Higashi l-l-3, Yatabe, Ibaraki 305, Japan. 0003-004)uE4l0506-965$02. 00 466 SHIMAZAKI ET AL,: SADANAGAITE AND MAGNESIO-SADANAGAITE

Introduction brown seams intercalated with limestone in the quarry. The classification and nomenclature of amphiboles by Myojin Island, one of islands known as the Shisaka Leake (1978)defines no lower limit of Si content in calcic Islands, consists largely of somewhat gneissosegranitic amphiboles,although a prefix "subsilicic" is recom- rocks and gneisswith some limestonebeds. Sato (1926) mendedwhen the number of Si is less than 5.75 on the first reported the occurrenceofclinopyroxene from skarn basis of 23 oxygens. The occurrence of amphibole with lenses in one limestone bed, and subsequently Kuno Si : 5.27has beenreported by Appleyard (1975)and the (1960) described this as titaniferous pyroxene, and necessity of new end member NaCa2Mg3Al2Si5Al3 Miyahisa et al. (1980)as fassaite.The dark colored lenses O22(OH)2("Al-pargasite") has been suggested(Bunch in the limestone bed include locally amphibolesof parga- and Okrusch, 1973;Doolan, Zen and Bence, 1978). site to magnesio-sadanagaitecomposition in addition to This contribution provides natural examplesof amphi- the above clinopyroxene. boles with lower Si than the above composition from two separate localities, Yuge and Myojin Islands, Ehime Occurrence and associated minerals Prefecture, Japan. The composition of these amphiboles According to the geological map compiled for Ehime is so different from that of pargasite with regard to the Prefecture (1962),Yuge and Myojin Islands are situated number of Si that they are proposed as new Si-poor near the boundary between the Paleozoic-MesozoicChi- members(Si < 5.5) of the pargasite series. The minerals chibu Belt and the Ryoke Metamorphic Bett (Fig. l). and mineral names, sadanagaiteand magnesio-sadana- Yuge Island belongs to the former belt with the intrusion gaite, have been approvedby the Commissionon New of the Mesozoic Hiroshima-type granitic rocks. Myojin Minerals and Mineral Names, IMA (CommissionNos. Island belongsto the latter belt, and weakly gneissose 80-27and 82-102).The names are for Emeritus Professor granitic rocks are associatedwith high temperature-low Ryoichi Sadanaga,Mineralogical Institute, University of pressure-type metamorphic rocks. Both localities are Tokyo, in recognition of his outstanding contributions to only about 15 km from each other, and are thought to the field of mineralogy and crystallography. Type speci- have similar geologic environments, although they are mens have been deposited in the Department of Mineral- located in diferent geologic belts. No tectonic zone ogy, the University Museum, University of Tokyo, Ja- separatesthem, and the boundary between the belts is pan. basedonly on the metamorphic grade. Both Yuge and Myojin are small islands located in the In the Yuge limestone quarry, sadanagaite-bearing Seto Inland Sea, southwesternJapan (Fig. l). In Yuge skarn occurs as seamsin limestone with variable widths Island, where a limestonequarry has been operated,a up to a maximum of 50 cm. The skarn seamsusually have sadanagaite-bearingvesuvianite skarn occurs as dark a symmetrical structure, that is, they consist of a wollas-

rrd t3s. o'+ + HONSHU ..i.,,,$ ------sS "t4 ll$'r'-- -t,' 5 '--.^*g gES

O SOKM 0t€rss0€E OR ilIIE

Fig. l. Location and simplified geology of the Yuge and Myojin Islands, Ehime Prefecture, Japan. SHIMAZAKI ET AL.: SADANAGAITE AND MAGNESIO-SADANAGAITE 467 tonite zone, a -vesuvianite zone, and a vesuvian- ent of the skarn, in contrast with the Yuge occurrence. ite-sadanagaite zone, traversing from limestone to the The skarn includes, besides clinopyroxene, various center of the seam. Sadanagaitemay be lacking in the amounts of spinel, vesuvianite, magnesio-sadanagaiteto central vesuvianitezone of some seams.The sadanagaite- pargasite, phlogopite and minor amounts of sphene, il- bearing zone occurs as a compact, dark brown band, menite, magnetite, pyrrhotite, apatite and perovskite. consisting of vesuvianite and sadanagaitewith minor Both clinopyroxene and magnesio-sadanagaitefrom this amounts of spinel, sphene, ilmenite and apatite. Sadana- locality are short-prismatic to granular in shape with a gaite appears as isolated prismatic crystals with a maxi- maximum diameter of a few hundred microns. mum length of I mm or as polycrystalline aggregatesin The composition of the clinopyroxene has been debat- matrix vesuvianite. The composition of sadanagaitesis ed since the first description by Sato (1926).Kuno (1960) quite variable with respect to SiO2as will be describedin showed that the clinopyroxene is rich in AlzOr (6.89 the following section and shown in Table l. wt.Vo) and TiOz Q.47%) by wet chemical analysis. Preliminary electron microprobe analyses show that Miyahisa et al. (1980)concluded that it is fassaitewith up the vesuvianite is rich in titanium with TiO2 contents of 5 to 5 wt.%oAl2O3 using the electron probe microanalyzer. wt.Vo or more. The spinel is hercynite with variable Most of the skarn lenses contain clinopyroxenes with amountsof the spinel molecule. Amounts of up to 5 wt.Vo compositions similar to those given by Kuno (1960)and Al2O3 are present in the sphene. Ilmenite has a small Miyahisa et al. (1980). The associated amphiboles are amount of the geikielite molecule. (ferroan) pargasite to less commonly magnesio-hasting- In Myojin Island, the magnesio-sadanagaite-bearing site. skarn occurs as a lens or as an irregularly shapednodule The bulk chemical compositions of the lensesare quite in crystalline limestone. Some lenses show a structure variable, and in some rare lensesthe compositionsof the similar to that of boudinage.The size of the lens or nodule clinopyroxene and amphibole become very Si-poor, and although variable rangesup to several tens of centimeters Al- and Ti-rich. Magnesio-sadanagaitegiven in Table l, in width. The occurrenceofthe skarn is reported in detail No. 4, is an example from an extremely Si-poor lens. The as a fassaite-spinelrock by Miyahisa et al. (19E0). As associatedclinopyroxene is also unusually Si-poor, with noted in their paper, clinopyroxene is the main constitu- the number of Si : 1.3 on the basis of 6 oxvsens. An

Table l. Electron microprobe analysesof sadanagaitesfrom the Yuge (Y) and Myojin (M) skarns

No. r (Y) 4 0,r) s (Y)

sio2 30.2 29.9 3I. I 32.L 33.5 29.5 Tio2 4.0 4.3 4.5 3.2 2.L 4.0 A1203 24.8 22.6 22.5 22.0 L9.7 23.2 FeOr L5.2 L7.4 L6.2 L3.7 17.8 15.4 MnO 0.1 0.3 0.4 0.1 0.5 0.3 Mgo 6.6 6.1 6-6 8.0 6.4 CaO L2.3 1r.9 L2,0 L2.5 11.9 1r. 9 Na2O r. u 0,6 0.6 o.7 L.2 K2o 3.7 3.7 3.6 3.8 3.r 3.5 Total 97.9 95.8 t I .5 96.1 96.2 97.2

Nrmbers of cations on the basis of 23 oxygens si 4.6il n.eo) q.ttl 4.e5) s.zl'l l.szl lrrV ,.rrj8'00 ..rnJt'oo ,.rrJt.oo ,.orjt.oo z.tale-oo 3.4sJ8-oo -, vr

Ti -J+ !e Fe2+ Mn M9 Ca 2.01 2.0r 1.99 r.99 I.97 L-97 2.07 2.07 2.00 2.00 1.96 1.96 Na 0.2e1_ -_ o.r7l o.tel o.zzl o.gzl o.2o'l K o.t.Jt'oo o.toJo'tt o.rrJo'tt o.rulo't' o.rrJo''e o..rlo'tt

*Total iron. Nos. l-3, 5: sadanagaite, 4: magnesio-sadanagaite, 63 Si-poor deri- vative of edenite-hastingsite series (Al.vr< Fe3+). 46E SHIMAZAKI ET AL.: SADANAGAITE AND MAGNESIO-SADANAGAITE

Table 2. Electron microprobe analysis of titaniferous fassaite ray intensitiesfor Si, Ti, Al, Fe, Mn, Mg, Ca, Na and K from the Myojin skarn, with cell dimensions and some optical were measured on standards and samples. The ratios propertres were converted into oxide weight percentagesusing the method of Bence and Albee (1968).Detailed descriptions rso of the analytical procedure and the correction factors on the basis of given (1970). Oxide wt. t slx oxygens used have been by Nakamura and Kushiro In the present study, the totals of the corrected weight sio2 34.0 si r.grl rrr > 2.00 percentagesof oxides are usually in the range of 96.0 to T!O2 6.8 Ar^' 0. 69 J 98.0Vo,with the remainder mainly due to H2O. Qualita- Al2o3 19.6 tive checks showed some amount of fluorine but no FeO* 8.4 in these amphiboles. Mgo 6.I appreciableamount of chlorine cao 25.O The compositions of amphiboles from both localities rangefrom sadanagaiteto pargasiteand less commonly to Total 98.9 Ca 1.03 I.03 hastingsite. Common features among these amphiboles are: (1) completeoccupancy of the B site by two calcium (2), a=9.740(21 A, b=8.829 c=5.31r(1) atoms, indicating that they are essentially calcic amphi- (I) based on 4-circle F=LOI.S2' boles, an{ (2) the predominanceof potassium over sodi- diffractometer data. um in the A Although the electron probe analyses 2Y"=go, ctz-35", xrr reddish purple, site. z': colorless to light yellow. lack ferrous and ferric iron determinations, meaningful Dispersion : very strong. estimation of the exact compositions was made by itera- tive calculations to satisfy the following two conditions: * Total iron (l) total numberof oxygensis 23.00,and (2) some Fe is taken as ferric so that AlIv = AlvI + Fe 3+ + 2Ti + Na + electron probe microanalysis of such a clinopyroxene is K. Through such calculations, the number of cations in given in Table 2. The amountsof MnO, Na2O and K2O the C site usually comes close to 5.00, indicating the are below the detectionlimit (<0. I wt.%). Its composi- validity of this procedure. tion is somewhatvariable with Si rangingfrom 1.3 to 1.4 Selected analyses (Table l) demonstratea wide range in one polished thin section. The amount of Fe3* was of Si from 5.5 to 4.5, and establish the definition of estimatedby calculation in order to satisfy the following sadanagaiteas a calcic amphibole ((Ca + Na) > 1.34,Nas 3+ two restrictions:O : 6 and Allv : Alvl + Fe + 2Ti. < 0.67)with Si < 5.5, (Na + K)e = 0.5' AlvI = Fe3* and This unusually Si-poor fassaite is comparable to those Ti < 0.50 per unit cell formula. This requires an extension reportedby Dixon and Kennedy (1933)from a sphene- to the silica-poor side ofthe edenite-pargasiteseries (after rich plagioclase-diopsidehornfels xenolith in a norite, by Leake, 1978) as shown in Figure 2. Sadanagaiteswith Dowty and Clark (1973)from the Allende meteorite, and Fe2* = Mg are common in the Yuge skarns, and those by Gross (1977) from an anofthite-wollastonite-gehlen- with Fe2+ ( Mg, for which the name magnesio-sadana- ite-pyroxene hornfels formed by thermal gaite is given, are typically found in the Myojin occur- of marls. The pyroxene in the Allende meteorite was rence (Table l). formed under an extremely reducing environment, and In someanalyses, such as No. 6 in Table I, the relation includes a large amount of Ti3+. The occurrence of AlvI < Fe3* is obtained after the calculation of the fassaitein this study with about 1.3 Si confirmsthat one estimated amount of ferric iron. According to Leake's third of the Si can be replaced by AlIv in the crystal (1978)nomenclature, such amphiboles with AlvI < Fe3+ structure of Ca-clinopyroxene under terrestrial Si-poor, could be a new speciescorresponding to the Si-poor and Al- and Ti-rich environments. derivative of the edenite-hastingsiteseries. Such amphi- Not only the clinopyroxene but some other minerals boles, in the present study, are rather rare, and the associated with magnesio-sadanagaitein the Myojin calculatedexcess of Fe3* over AlvI is not significantif we skarn have unusually Al- and/or Ti-rich compositions, consider the error included in the estimation of the similarto those of the Yuge occurrence.Spinel from the amount offerric iron. The establishmentof new speciesat Myojin skarn contains small amounts, tp to I wt.Vo the silica-poor side of the edenite-hastingsiteseries must Cr2O3,in solid solution.Ilmenite usually includes several remain for future studies. Although sadanagaitesare mole percent geikielite. Perovskite is associatedwith defined as having Ti < 0.5 in the formula, analysesshow magnesio-sadanagaitein the Myojin skarn. that the numberof Ti may exceed0.5 (e.g.Nos. 2 and 3 in Table 1). According to Leake's (1978) nomenclature, Chemistry such analysesrepresent Si-poor derivatives of kaersutite. Because it was difficult to separate enough sadana- The excessof Ti over 0.5 is very small in thesesamples, gaitesfor conventionalwet-chemical analysis, polished and we will not discussthe statusof Si-poor derivatives of thin sections of sadanagaite-bearingskarns from both kaersutite. localities were prepared for electron probe analyses.X- In sadanagaitesfrom both localities, the amount of K SHIMAZAKI ET AL.: SADANAGAITE AND MAGNESIO-SADANAGAITE 469

Calcic Anphibotesr (Ca + Na)" Z 1.34, NaB< 0.6?

(Na + K)A a 0.50, Ti< 0.50, r.3+ ='etVr

8.00 < a4 6. 50 6.25 5.50 4.00 si 1.00

PARGASITIC PARGASITE IIORNBLANDE SII,ICIC EDENITIC MAGNESIO- 0.70 EDENITE EDENITE SADANAGAITE

FERIOAN FERROAN 0.50 PARGASITIC PARGASITE HORNBLENDE

0.30 SILICIC FERRO- FERRO- FERRO- EDENITIC SADANAGAITE FERRO- EDENITE EDENITE HORNBLENDE FERRO- PARGASITIC PARGASITE HORNBLENDE 0.00 Ie {lag+re2+)

Fig. 2. The position of sadanagaiteand magnesio-sadanagaitein the classificationof calcic amphibolesafter Leake (1978). alwaysexceeds that of Na. According to Leake's (1978) ed with the titaniferous fassaite,the composition of which suggestion, potassium (K = 0.50) or rarely potassian is given in Table 2. The amphiboles from the Myojin (K = 0.25-0.49) (magnesio-)sadanagaiteis the recom- skarn tend to be Mg-rich, and range mainly from magne- mended name for the present amphiboles.In experimen- sio-sadanagaiteto pargasite. tal investigation of the Na-K substitution in some amphi- boles Hinrichsen and Schiirmann (197D failed to Table3. X-raypowder diffraction data for magnesio-sadanagaite synthesizepargasite with Na5eK56to NaaKlgeat tempera- tures between 750-1000"Cand pressuresbetween 1 and 4 ro do i aa i r,tt ro doi d.i hkl kbar. The authors, however, suggestedthat extensive r0 9.00 9.00r o20 10 1.909 1.9091 510 substitution of Na by K in pargasitic amphiboles would 80 8.48 8.47* 1I0 3 r.892 r.893r 4GI not be impossible,as shown in the presentstudy. 5 4.97 4.96r rrl 3 1. 865 I . 857 442 Becauseall sadanagaitesin this study have high IVNa t5 4.80 4,80r 200 1.865 19r ratios, large replacementof Si by Al in the T site may be 10 4.50 4.50r 0,40 5 1.829 1.829i 530 crystallochemically necessaryfor the entry of K into the 3 4.01 4. olt tlt 5 1.801 1.801* 0.10.0 A site. It is uncertain whether high K substitution in the A 40 3.39 3.39r t3r 2 L.778 L.778t 5L2 100 3-28 3.28r 240 2 I.7158 1.713 332 site is an essentialfeature of the Si-poor member of calcic 70 3.15 3.15* 310 I.7II 313 (1975), amphiboles. Appleyard however, gives an exam- 50 2.951 2.949* 22L s r.69s- 1.696 2sz E ple of Na-rich amphibole in the hastingsite series with 30 2.A23 2.823* 330 2 r. Gg5 t. egl* .39I Si = 5.27 from metasomatic alkaline gneissesat Wolfe, 45 2.766 2.7681331 30 1.654 1.654* 45I Ontario. Becausethe significanceof the K./Na ratio in the 60 2.707 2.708* 151 5 1.643 r.642* 480 amphibole structure has not yet been established, the 35 2.594 2-594t O6L 3 r.614 1.614*r.11.0 large KA.{a value should not be included in the definition 15 2.57a z-stat zo2 5 1. 599 r. 600 500 of sadanagaite. 13 2-392 2.392' 350 I. 594 I53 As noted above, amphiboles in the Yuge skarn are t5 2.355 2.355 42L 10 t. 559 I .560 402 chiefly associated with vesuvianite. Their Si content 2. 358 3sI r. s60 602 rangesfrom 4.5 to 6.0, that is, from sadanagaiteto ferroan s 2.3r?B 2.318 3L2 3 L.529 L.529t 263 3 2.23s- 2.237 zt2 6 r .507 t. 507* 551 pargasite.Extremely low Si contents are causedpartly by B 55 2-L62 2-L63. 26L 3 L.4768L.476 153 (e.g. the relatively high Ti contents in the mineral Nos. L2 2.051 2.O54 202 L.476 2.Lo.2 1-3 and 6 in Table l). On the other hand, amphiboles in 2.052 402 5 1.457 1.457*3.11.0 the Myojin skarn are usually associatedwith clinopyrox- 15 2-020 2.O2L* 35L to L.452 r.4521 66I enes, and Ti tends to be concentrated in clinopyroxene 5 2.004 2.005* 3?0 5 1.370 1.370.512 rather than the associatedamphibole. Analysis No. 4 in r Table I is an example of an amphibole poorest in Si Included in the leagt squares refinment of the (:5.0) from the Myojin skarn.This amphiboleis associat- unit cell dinensions 470 SHIMAZAKI ET AL.: SADANAGAITE AND MAGNESIO-SADANAGAITE

X-ray crystallography and physical properties rather reducing environment. On the basis of a bulk X-ray singlecrystal studiesshowed these amphiboles chemical analysis of the skarn lens, they concluded that to be monoclinic, with possible space group A, Cm or the amphibolite facies rock was originally derived from an Al-rich C2lm. An X-ray powder diffraction diagram of magnesio- sediment such as a laterite, intercalated with sadanagaitewas recorded with a powder diffractometer, Iimestone. The similar nature of the Yuge skarn strongly whereas the pattern of sadanagaitewas obtained with a suggests that it was also derived from similar Al-Fe-Ti- rich Gandolfi camera due to the very small quantity of avail- sediments intercalated with limestone. Hydrothermal able material. Least squares refinements of the unit cell solutions may have aided the exchange of material be- dimensionsfrom about 20 measuredreflections for sadan- tween the aluminous sediments and the surrounding limestone. (1978), agaite and from over 30 for magnesio-sadanagaitegave According to Iwao occurrences of Fe- thefollo-wingvalues: a:9.922(10), b = 18.03(2),c= Al-Ti-rich metamorphic rocks are known widely in the late Paleozoic to Triassic formations of Japan. The Yuge 5.352(9)4, B : 105.30(10)'for sadanagaite;and a : and Myojin occurrences are additional examples of later- 9.99(2),D: 18.008(3),c= 5.354(2)4,P= 105.55(2)'for magnesio-sadanagaite.No essential diference in the itic sediments formed during these times. powder pattern is recognizedbetween magnesio-sadana- Acknowledgments gaite (Table 3) and sadanagaite;their patterns are also wish similar to those of Si-poor calcic amphiboles such as We to expressour thanks to late ProfessorM. Miyahisa and to ProfessorH. Momoi, of the Ehime University, who kaersutitegiven in JcpDSCard No. 17-478.The calculated provided us with the opportunity of studying theselocalities and densityis approximately3.30 tg/cm3) for sadanagaiteand continuously encouragedour studies. We are much indebted to 3.27 (gl cm3)for magnesio-sadanagaite. Dr. A. Kato of National Science Museum, Japan, and to Both specieshave very similar physical properties, ProfessorsH. Winchell of Yale University and B. E. Leake of dark brown to black in color with a vitreous luster. The the University of Glasgow, for their critical discussion and color of the streakis very light brown. Cleavage{110} is valuable suggestions. perfect, and characteristic amphibole cleavagesare obvi- ous in thin sections.The Mohs hardnessis approximately References 6. Sadanagaiteas well as magnesio-sadanagaiteis optical- Appleyard, E. C. (1975)Silica-poor hastingsiticamphiboles from ly biaxial;positive with 2V : 80-90' (obs.),86' (calc.)for metasomaticalkaline gneissesat Wolfe, easternOntario. Ca- sadanagaite,and with 2V closeto 90'(obs.), 88'(calc.)for nadian Mineralogist, 13, 342-351. magnesio-sadanagaite.The refractive indices Ne a = Bence, A. E. and Albee, A. L. (1968)Empirical correction and oxides. 1.673(2),F = 1.684(2),y: 1.697(2),c: Z : 28"(sadana- factors for the electron microanalysis of silicates -- Journalof Geology,76,382-403. gaite)and a 1.674(2),B = 1.686(2),y = 1.699(2),c:Z : Buddington,A. F. and Lindsley, D. H. (l%4) Iron-titanium 26" (magnesio-sadanagaite).Both are pleochroic under oxide minerals and synthetic equivalents. Journal of Petrolo- the microscope from : pale : greenish 7' brown to Z' gy,5, 310-357. : brown (sadanagaite) and from X' colorless to Z' Bunch, T. E. and Okrusch, Martin (1973)Al-rich pargasite. brownish yellow (magnesio-sadanagaite).The color un- American Mineralogist, 58, 721J26. der the microscopeand pleochroismbecome paler and Dixon, B. E. and Kennedy, W. Q. (1933)Optically uniaxial weaker,respectively, with increasingSi contentof sadan- titanaugite from Aberdeenshire. Zeitschrift fiir Kristallogra- agaites. These properties for sadanagaitewere obtained phie, (A), 86, ll2-120. using grains with some compositional variations. As Doolan, B. E., Zen, E-An and Bence, A. E. (1978)Highly sadanagaitewith Si close to 5.0 is predominantin the aluminous : Compositions and occurrencesfrom specimen,it is concluded that these properties represent southwestern Massachusetts.American Mineralogist, 63, 1088-1099. those for sadanagaitewith Si : 5.0. The properties for Dowty, Eric and Clark, J. R. (1973) refinement magnesio-sadanagaite are thought to also representthose and optical properties of a Ti3* fassaite from the Allende - for magnesio-sadanagaitewith Si 5.0, sincethey have meteorite. American Mineralogist, 58, 230:242. been measuredusing grains separatedfrom the specimen Ehime Prefecture (1962) Geological map of Ehime Prefecture which has beenfound to be relatively homogeneousand with an explanatory textbook, 182p. (in Japanese). provided the chemical compositionof analysisno. 4 in Gross, S. (1977) The mineralogy of the Hatrurim Formation, Table l. Israel. Bulletin of Geological Survey of Israel, No. 70, l-80. Hinrichsen, Th. and Schiirmann, K. (1977)Experimental investi- Genetic considerations gations on the Na./K-substitutionin edenites and pargasites. NeuesJahrbuch fiir Mineralogie,Abhandlungen, 130, 12-18. Miyahisa et al. (1980) analyzedthe compositionsof Iwao, Shuichi (1978)Re-interpretation of the chloritoid-, stauro- magnetite and ilmenite associatedwith fassaite from the lite- and emery-like rocks in Japan. Chemical composition, Myojin locality. On the basisof Buddingtonand Linds- occurrence and genesis. Journal of Geological Society of ley's (1964)geothermometer, they estimatedthe tempera- Iapan,84, 49-67. ture of formation to have been 600'C, and the oxygen Kuno, Hisashi (1960) Notes on rock-forming minerals. (16) fugacity somewhat greater than 10-20 atm, reflecting a Titaniferous pyroxene, spinel, and magnetitein hornfels from SHIMAZAKI ET AL.: SADANAGAITE AND MAGNESIO.SADANAGAITE 471

Sisaka-zimaIslands, Japan. Journal of Geological Society of Nakamura, Yasuo and Kushiro, Ikuo (1970) Compositional Japan,66, 616-61E. relations of coexisting orthopyroxene, pigeonite and augite in Leake, B. E. (1978) Nomenclature of amphiboles. American a tholeiitic from Hakone Volcano. Contributions to Mineralogist, 63, 1023-1052. Mineralogy and Petrology, 26, 265-275. Miyahisa, Michitoshi, Momoi, Hitoshi, Minagawa, Tetsuo, Sato, Hokoto (1926) On mangan-titanpyroxene from Shisaka- Noto, Shigetoshi and Matsueda, Hiroharu (1980) Fassaite jima. Proceeding of 3rd Pan-Pacific Science Congress, 803- from the Ryoke metamorphic rocks of Shisaka-jima,the Seto E04. Inland Sea,Japan. Journal ofJapaneseAssociation ofMineral- ogists, Petrologistsand Economic Ceologists,75,25-29 (in Manuscript received, March 16, 1981; Japanese). acceptedfor publication, December 27, 1983.