Johannsenite from Teragōchi, Okayama Prefecture, Japan

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Kyushu University Institutional Repository

Johannsenite from Teragōchi, Okayama Prefecture, Japan

Momoi, Hitoshi

Faculty of Science, Kyushu University

https://doi.org/10.5109/1543612

出版情報：九州大學理學部紀要 : Series D, Geology. 15 (1), pp.65-72, 1964-06-25. 九州大学理学部バージョン：

権利関係：

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Mem． Fac． Sci．， Kyushu Univ．， Ser． D， Geology， Vol． XV， No．1，

pp．65−72，2text一毎s，5tables， plate 6． May 31，1964

Johannsenite from Terag6chi， okayama Prefecture， Japan

By Hitoshi MoMoI

Abstract

Anew occurence of johannsenite has b㏄n found in manganese ore deposits at Terag6chi， Okayama Prefecture， Japan． The mineral occurs as a chief component of the massive manganess ore． Aggregates of bluish johannsenite crystals look quite similar to those of skam hedenbergite． It has following chemical composition： SiO2 48．02，TiO2 tr．， Al2030．80， Fe2030．30， FeO 3．20， MnO 27．53， MgO O．48， CaO 19．10，

Na200．25， K200．04， H20＋0．23， H20−0．00， total 99．95 wt．％． Silky green variety with following composition was also found： SiO248．18， Al2030．80， Fe2031．00， FeO 4．82，MnO 26．29， MgO O．47， CaO 18．79， Na200．20， K200．04， H20＋0．10， H20−0．00，

total 100．69 wt．％． Optical properties for the blue johannsenite：α＝1．707，β＝1．720，

γ＝1．736，γ一α＝0．029，2V（十）72°． Sp． gr．（blue variety）＝3．54（21°C）二 Unit cell dimensions ol）tained by X−ray powder method are：（blue variety）ao＝9．916A， bo＝9．107

むむむくコむ

A，co＝5．280 A，β＝74°49 ：（green variety）ao＝9．913 A， bo＝9．104 A， co＝5．274 A，βニ 74°49． Powder data and infrared spectra are also presented together with the heat−

ing effect of johannsenite．

Introduction

Occurrences of johannsenite have been recorded from Italy， Mexico， Aus−

tralia （Broken Hill）， New Jersey （Franklin Furnace）， New Mexico， and Oregon． Professor YosHIMuRA adviced me to study a specimen looking like hedenbergite Iabelled as from the Onagusa mine， Okayama Prefecture in the KO collection of Kyushu University（YosHIMuRA，1952， P．103）． In 1959，

Ivisited a manganese mine a七Terag6chi，1km． northwest of七he Nagusa

copper mine， Katsuyama town， Maniwa Country， Okayama Prefecture芥， and found there a mineral looking similar to七he specimen of the KO collection，

in some piles of manganese ores． At that time， the deposits had not been working． The locality is shown in Figure 1． The specimell was identi6ed as johannsenite by chemical analyses， X−ray powder method， optical properties，

and infrared absorption． This paper is a mineralogical description of the johannsenite， found for the 6rst time in Japan．

The manganese ore deposits are developed in siliceous limestone and in green phyllite belonging七〇the Permian limestone beds and the Sangun meta−

morphic rocks（YAMADA，1941：MITSUNO，1963）． It was unable for me to observe the mode of occurrence of johannsenite in situ because of the aban−

doned mine． Only one massive outcrop， bearing johannsenite was recognized，

Manuscript received October 31，1963．

＊岡山県真庭郡勝山町寺河内

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ONIANA

0κ冷γ質〃凶PRεF江πノRE

苓ノ×

TERAGOCHI

o

Fig．1． Location of the manganese ore deposits bearing johannsenite（×）at Teragδchi， Okayama Pre−

f㏄ture， Japan．

being heavily colltaminated with manganese dioxide． This ore body has a strike of N60°W， and a dip of NE 70°， which are near the general trend of the wall rocks， and is composed of johannsenite， manganese oxides， rhodonite，

quartz， calcite， galena， and sphalerite．

The main portion of johannsenite is seen fully al七ered to manganese dioxide，（todorokite with low crystallinity） and to powdery opaline silica．

The oxide ore has fibrous radial texture pseudomorphous after johanllsenite．

Tiny rhodonite crystal are seen around a quartz vein which traverses the johannsenite aggregate． Simultaneous crystallization of calcite and sulphides are observed among rhodonite crystals． Quartz veins are also seen accom−

panied by a small amount of galena and sphalerite． Bustamite and wollasto−

nite were not found in the johannsenite deposits．

Physical properties

Large johannsenite crystals are up to 15 cm． in length， and 5 mm． in width， and show long columner or 6brous texture． Radial or parallel growth

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Johannsenite from Teragδchi， Okayama Prefecture， Japan 67

is common． Color is light cobalt blue， bluish green or dark green with resinous to silky luster． Bluish crystal， surrounded zonally by greenish one， apPears very similar to that of hedenbergite． Specific gravity and optical properties were measured on a bluish crystal． Specific gravity；is 3．54 at 21°C（pycno−

meter method）． Optical proper七ies：α＝1．707，β＝1．720，γ＝1．736，γ一α＝0．029，

2V（十）72°， b＝Y， twinning plane（100）， C〈Z＝55°．

Chemical composition

Chemical analyses of blue and green johannsenites were made on pure ma七erials prepared by hand picking． The fiame photometric method was adopted for alkalies， and the common gravimetric mehtod for the other metal oxides． The results are given in Table 1， together with some other previous data． Atomic ratios were calculated on the basis of six oxygens wi七h the fol−

Iowing results；

BI％e勉αγ e吻（Nao．02Mgo．03Cao．85）o．go（Mno，g6Fe o．11Fe o．01Alo．02）1．10（Alo．02Si1．g8）2．ooO6．oo Gγθθ％勿αがθ垣（Nao．02Mgo．03Cao．83）o．88（Mno．91Fe o．17Fe o．03Alo．02）1．13（Alo．02Si1．98）2．ooO6．oo

80th results are very close to the ideal formula of johannsenite， CaMnSi206．

Differellce of color be七ween the two varieties lnay probably be due to their irOn COntentS．

Table 1． Chemical compositions of johannsenites Broken Hill

Australia

HUTTON

1956

Mt． Civillina Italy

SCHIAVINATO

1953

Teragδchi＊

Japan

Color _Pale green Light blue

Sio2 Tio2 Al203 Fe203

FeO MnO MgO CaO

Na20

K20

H20＋

H20−

CO2

48．39 nn．

0．58 nil？

13．44 14．14 2．19 20．79 0．05 0．09 0．08 0．12

47．90

tr．

0．25 0．98 26．81 0．96 21．62

0．26 0．50 1．11 100．39

48．02 tr．

0．80 0．30 3．20 57．53 0．48 19．10 0．25 0．04 0．23 0．00

Silky green

Total 99．87

48．18

0．80 1．00 4．82 26．29 0．47 18．79 0．20 0．04 0．10 0．00

99．95 100．69

＊Analyst： H． MoMoI

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X ray powder study

X−ray powder patterns were obtained by a Shimadzu X−ray diffractometer with五ltered Fe Kαradiation． The experimental conditions were：30 KV，

10mA， full scale 500 counts per second，七ime constant 2．50r 5．O seconds， scan−

ning speed 20r 4 degrees per minute， slits 3−2−0．4 mm． The readings of diffraction angles were corrected with an internal s七andard of silicon． The unit cell dimensions were determined from the following reflections：（600），

（060），（350），（531），and（750）． The indexing was made in referring to those of clinopyroxene by KuNo and HEss（1953）and by YAMAGucHI（1961）． The results are lis七ed in Tables 2 and 3． The observed and calculated d−values are in good agreement． The unit cell dimensions of七he Thrag6chi johannsenites

Table 2． X−ray powder data for johannsenite（blue）from Teragδchi， Okayama Prefecture， Japan

む（Fe Kα五1tered with Mn，λ＝1．9373 A）

1 2θ

W

00 0 1232 1 111 1 1 11 49530601560817246212262527229 W WB W

B

1

_一1

6512一126

B ⁷⁷1⊥9一9錫3

33444445555555556666677777

^π

b344 7834478123345678124591234 5 2 ⁰

_β一72

撒ユ46撒釜22え撒日2メ6量βεβ三 8102275 097518600224828533041 70453

79 83 85

む

dob8．（A） ^むdcalc．（A）

640040754 52074850 2939055470808687979171207

8 ワ・ 10 0 々bOV4 1⊥

男題︒2器霞㌶泌認翌6︒299額蟹四69肪器竺駆誕竺6

．・．・・・・・・・・・・・・・ ⁝

● ⁝

◆ ．・・ ● ・・ ⁝

．

64433222222222222221111111111 111 11 4119451950421862

045848650

52381907361782870684116209782584011775109859303064943496417339971894531998541153 5752009655332211110009838766666555555544

ロガロロのロコびコヴロコびコココロロコココロのコロのヴロロ

6443332222222222222221111111111111111111

︷︷︷

︷

H

一10 00 20 20 21 10

h一1202233120433133440241354104525603660453

1131．210200 1112一123031212041一〇202323110．2150424031233000235021026042．3152

B： 1）road， w：weak．

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Johannsenite from Teragδchi， Okayama Prefecture， Japan 69

Tal）le 3、 Unit cell dimensions of johannsenites

L㏄ality Reference ^a。（A） ^b。（A） ^c。（A） β

Teragδchi Japan

Ditto．

Civillina Italy Herault California

（Hedenbergite）

This paper

（Blue）

（Green）

SCHIAVINATO 1953 KUNO and HEss

1953

9．916 9．913 9．81

9．854

9．107 9．104 9．02

9．024

5．280 5．279 5．26

5．263

74°49

74°49 75°

75°40

are somewhat larger than those of an Italian specimen（ScHIAvINATo，1953）．

The calculated densi七ies are 3．56g （blue） and 3．57g （green）．

In丘ared abso巧ption spectra

The infrared absorpiton spectra of blue johallnsenite were obtained with aHitachi double beam infrared spectrometer using KBr disks． The results are shown in Table 4 and Figure 2． The absorptions by CO2 and H20 are excluded because they were probably contaminated in air． The spectra of hedenbergite（FeO 18．75 wt．％）from the Mitate mine， Miyazaki Prefecture are also shown in the same table and figure for comparison，s sake． It is clear that both minerals have very close resemblances in absorption． The absorp−

tions of johannseni七e are observed a七七he slightly Ionger sides in wave length than those of hedenbergite owillg to the absorp七ion difEerences between ferrous iron in hedenbergite and divalellt manganese in johannsenite．

Table 4． Infrared absorption spectra of johannsenite， its heating product， and related minerals

Hedenbergite Mitate mine

Johannsenite ］ヨ【eated johann8enite Bustamite

Teragochi Kanoiri mine

1060

955 905 855 660

S

一

S

W

S

W

V

1062

952 910 860

S一SmS

¹⁰⁸⁰₁₀₂₀

945 905

675 S S s S

VW

1085 1025 940 905

685

SSSS一W

（Wave加mber， cn1−1）

Heating Product of johannsen、ite

Johannsenite has a modi丘cation belonging to a high temperature form，

called bustamite． This is a well known faCt since johannsenite was named

（ScHALLER，1938）． The johannsenite from Terag6chi， described here， was also

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9．o

WAVE LENGTH

lo．o

ロOO OO IOOO 900 800

●8 WAVE NUM8ER ㎝ Fig．2． Infrared absorption spectra

A： Hedenbergite from the Mitate mine， Miyazaki Pyefecture．

B： Johannsenite from Teragδchi， Okayama Pref㏄ture．

C： Heated johannsenite， ditto．

D： Bustamite from the Kanoiri mine， Tochigi Prefecture．

easily modified into bustamite by heating a七1000°C for l hour in air． The heating Product with pale grey color was examined by the X−ray powder method and by the infrared absorption spectra in七he same condition to above．

The results for the blue specimen are shown in Tables 4 and 5， and in Fligure 2．

The infrared absorption spec七ra of the heated johannsenite were compared with those of bustamite from the Kanoiri mine， Tochigi Prefecture． They agree closely with each other．

The X−ray powder data for the heated materials from Japan and from Australia（HuTToN，1956）are in good agreement in spite of the difference in iron content （FeO 320 in Japanese and 13．44 wt．％ in Australian）． The contents of calcium in the original johannsenite were， CaO 19．10 in Japanese and 20．79 wt．％in Australian． The structure of the heated products may be

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Johannsenite from Teragδchi， Okayan｝a Prefecture， Japan 71

Table 5． X−ray powder data of heated johannsenite

Johannsenite， heated in air，1000°C，1hr．

Terag㏄hi， Japan

1 d（A）

8

bb ︑O b

123

835125249一〇〇689982092312一8

10 10

−寸⊥（b551⊥OV

7．52

566074 6457379382 638308564239 1356072444 749927

コ

5

且

3 333332 2222222222 111111 2 0一〇コ㊤95549432ユ一〇〇βココ6

Ferroan johannsenite，

heated in air，1070°C，

15．5hrs． Broken］Hill，

Australia 1

1121172一32351101381一4333311一434

d（A）

PO 5 5

549218587619602396

5。

⑳89

霞︒5竺釜肪︒4塁巧豊5︒石釦％U晶％一謬68

7544443 3333222222 2222211 111

ココタおロロコココココココロのコロ

controled more effectively by七he calcium atoms．

Acknowledgm使t

Iexpress my sincere七hanks to Professor Toyofumi YosHIMuRA of Kyushu University for his guidance during七his work and also for his reading the manuscrip七． Thanks are due to Dr． Haruo SHIRozu for his reading the manu−

script and much advice， to Dr． Mayumi YosHINAGA for his discussion and advice， and also to Dr． Kichinosuke HENMI and Dr． Chiharu MITsuNo of Oka−

yama University， to Mr． Ichiro ToMIoKA， the mine−owller at Teragochi for their kind guides and advices in the 6eld work． Fur七her， this work was partly indebted to the Grant in Aid for Scientific Researches from the Department

＜）fEducation of Japan．

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Re允rences

ALLEN， V． T． and FAHEY， J． J．（1953）： Johannsenite and ferroan johannsenite at Vanadium，

New Mexico．．4仇．刀弼πθγ．，38，883−890．

HuTToN， C． O．（1956）： Manganpyrosmalite， bustamite， and ferroan johannsenite from Broken Hill， New South Wales， Australia． A仇．1協％θ㌍．，41，581−591．

KuNo， Hisashi and HEss，正1． H．（1953）： Unit cell dimensions of clinoenstatite and pigionite in relation to the common pyroxenes．∠4糀． Jb耽． Soτ．，251，741−752．

MITsuNo， Chiharu（1963）： Zur Kenntnis des Oberpal50zoikums in Ostlichen Chugoku， SUdwest・

Japan． GθoZ．」￠θp‡．1五γ08んτ？ηα σγ励勿．，γ20．12，419−443．

ScHALLER， W． T．（1938）：Johannsenite， a new manganese pyroxene． A仇．1協％θγ．，23，575−

582．

ScHIAvlNATo， G．（1953）： Johannsenite of the deposit of manganese containing silicates at Mount Civillina， near Recoaro（Vicenza， Italy）．丑θη（1．80￠．勿仇θγ．撹α1．，9，210−218．

YAMADA， Setsuo（1941）：Geologic map of Japan， Kuze，， sheet． Scale 1：75，000． Geol． Surv，

Japan （1951）．

YAMAGucHI， Masaru（1961）：Chrome−diopsides in the Horoman and Higashi−Akaishi Perido−

tites， Japan． 1晩γ7τ． Fαo． S碗．，1ζyμ8んτL σ？zぜ勿．， Sθγ．1）， Gθol．，10，（2），233−245．

YosHIMuRA， Toyofumi（1952）：娩％9αηθ8θdθpos偽げみPαπ． Manganese Investigation As−

s㏄iation． 567 PP（in Japanese）．

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Hitoshi MOMOI

Johannsenite from Terag6chi， Okayama Prefecture

Plate 6

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Fig．1−2．

●

1

2．

Fig．3−4．

3．

4

Polished hand specimens of johannsenites from Teragδchi， Okayama Pre−

f㏄ture．

Spherulitic green johannsenite（J）cutted by quartz vein（Q）with silicified aureoles and by sphalerite vein （S）．

Fibrous green johannsenite（J）being partially replaced by pink rhodonite

（R）． Lower part（Q）consists of rhodonite（grey）， sphalerite（dark spots），

and quartz（white）．

Microphotographs of Johannsenite−rhodonite ore． Crossed nicoles．

Relicts of johannsenites（J）replaced by rhodonite （R）and carbonitization along the columner texture of johannsenite．

Idiomorphic rhodonites（R）and calcites（C）replaced johannsenite（J）．

Photos by H． MoMOI

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Mem． Fac． Sci．， Kyushu Univ．， Ser． D， Geology， Vol． XV

1

シぷ

ーe麟欝難ー

套盤癖癖難曝欝

0

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Plate 6

Johannsenite from Teragōchi, Okayama Prefecture, Japan

Kyushu University Institutional Repository