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Armalcolite

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Formula:
(Mg,Fe
2+
 
)Ti
 
2
O
 
5
System:OrthorhombicColour:Grey
Hardness:5
Name:
Named in 1970 by A. T. Andersen, T. E. Bunch, Eugene N. Cameron, S. E. Haggery, F. R. Boyd, O. B. James, K. Keil, Marun Prinz, Paul Ramdohr, and A. El Goresy. This name is in honor of the first three astronauts who traveled to Earth's Moon. The name is an acronym derived from the last names of Neil Alden ARMstrong (b. 1930), Edwin Eugene ALdrin (b. 1930) and Michael COLlins (b. 1930), the Apollo 11 astronauts who collected the type samples.

Classification of Armalcolite

IMA status:Approved
Strunz 8th edition ID:4/C.24-10
Nickel-Strunz 10th (pending) edition ID:4.CB.15

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
B : With medium-sized cations
Dana 8th edition ID:7.7.1.2

7 : MULTIPLE OXIDES
7 : AB2X5
Hey's CIM Ref.:7.9.21

7 : Oxides and Hydroxides
9 : Oxides of Ti
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Type Occurrence of Armalcolite

Type Locality:Tranquillity Base (Apollo 11 landing site), Mare Tranquillitatis (Sea of Tranquility), The Moon
General Appearance of Type Material:subhedral to anhedral grains to 300 µm across
Place of Conservation of Type Material:Lunar Science Institute, Houston, Texas, USA
Year of Discovery:1970
Geological Setting of type material:in Ti-rich basalt and microbreccias of lunar samples, formed at low pressures and high temperatures

Occurrences of Armalcolite

Geological Setting:in salic volcanics; in ultramafic rocks, lamproites and kimberlites; in terrestrial impact craters; in inclusions in carbonaceous chondrites; rarely in granite pegmatites

Physical Properties of Armalcolite

Lustre:Metallic
Diaphaneity (Transparency):Opaque
Colour:Grey
Hardness (Mohs):5
Density (measured):4.94 g/cm3
Density (calculated):4.64 g/cm3

Crystallography of Armalcolite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:a = 9.743Å, b = 10.023Å, c = 3.738Å
Ratio:a:b:c = 0.972 : 1 : 0.373
Unit Cell Volume:V 365.03 ų (Calculated from Unit Cell)
Z:2
X-Ray Powder Diffraction:
d-spacingIntensity
3.468 (100)
1.958 (80)
2.763 (25)
2.454 (25)
2.235 (15)
2.199 (15)
2.414 (10)
Comments:Recorded on type material

Optical Data of Armalcolite

Type:Biaxial
Type:Anisotropic
Anisotropism:Strong, pale grey to dark bluish gray
Reflectivity:
450 nmR1=14.1%R2= 15.2%
470 nmR1=14.0%R2= 15.0%
500 nmR1=13.8%R2= 14.7%
520 nmR1=13.7%R2= 14.5%
546 nmR1=13.4%R2= 14.4%
586 nmR1=13.3%R2= 14.3%
620 nmR1=13.2%R2= 14.2%
640 nmR1=13.0%R2= 14.1%


Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 15.2%.
R1 shown in black, R2 shown in red
Colour in reflected light:Grey to tan
Pleochroism:Visible

Chemical Properties of Armalcolite

Formula:
(Mg,Fe
2+
 
)Ti
 
2
O
 
5
Simplified for copy/paste:(Mg,Fe2+)Ti2O5
Essential elements:Mg, O, Ti
All elements listed in formula:Fe, Mg, O, Ti
Analytical Data:Electron microprobe analysis of type material; total iron calculated as FeO
TiO2 (72.0)
Al2O3 (1.48)
V2O5 (0.07)
Cr2O3 (1.94)
FeO (14.7)
MnO (0.07)
MgO (8.7)
CaO (0.32)

sum 99.28 wt.-%
Empirical Formula:
(Mg
 
0.46
Fe
2+
0.44
Al
 
0.06
Cr
 
0.06
Ca
 
0.01
)
 
=1.03
Ti
 
1.92
O
 
5

Relationship of Armalcolite to other Species

Series:Forms a series with Pseudobrookite (see here)
Related Minerals - Nickel-Strunz Grouping):

- +
4.CB.05Brizziite
NaSb
5+
 
O
 
3
4.CB.05Corundum
Al
 
2
O
 
3
4.CB.05Ecandrewsite
(Zn,Fe
2+
 
,Mn
2+
 
)TiO
 
3
4.CB.05Eskolaite
Cr
 
2
O
 
3
4.CB.05Geikielite
MgTiO
 
3
4.CB.05Hematite
Fe
 
2
O
 
3
4.CB.05Ilmenite
Fe
2+
 
TiO
 
3
4.CB.05Karelianite
V
3+
2
O
 
3
4.CB.05Melanostibite
Mn
2+
 
(Sb
5+
 
,Fe
3+
 
)O
 
3
4.CB.05Pyrophanite
Mn
2+
 
TiO
 
3
4.CB.05Akimotoite
(Mg,Fe
2+
 
)SiO
 
3
4.CB.05Auroantimonate
AuSbO
 
3
4.CB.05Romanite
(◻,Pb,Ca)UFe
2+
2
(Ti,Fe
3+
 
)
 
6
Ti
 
12
O
 
38
4.CB.05UM1998-11-O-AuHSb
Au
+
2
Sb
3+
 
O
 
2
(OH)
4.CB.05Tistarite
Ti
3+
2
O
 
3
4.CB.10Avicennite
Tl
 
2
O
 
3
4.CB.10Bixbyite
Mn
3+
2
O
 
3
4.CB.15Pseudobrookite
Fe
 
2
TiO
 
5
4.CB.20Zincohögbomite-2N2S
[(Zn,Al,Fe
2+
 
)
 
3
(Al,Fe
3+
 
,Ti)
 
8
O
 
15
(OH)]
 
2
4.CB.20Zincohögbomite-2N6S
[(Zn,Mg)
 
7
(Al,Fe
3+
 
,Ti)
 
16
O
 
31
(OH)]
 
2
4.CB.20Magnesiohögbomite-6N6S
[(Mg,Fe
2+
 
)
 
3
(Al,Ti,Fe
3+
 
)
 
8
O
 
15
(OH)]
 
6
4.CB.20Magnesiohögbomite-2N3S
[(Mg,Fe
2+
 
,Zn)
 
4
(Al,Ti,Fe
3+
 
)
 
10
O
 
19
(OH)]
 
2
4.CB.20Magnesiohögbomite-2N2S
[(Mg,Fe
2+
 
)
 
3
[Al
 
7
(Ti,Fe
3+
 
)]O
 
15
(OH)]
 
2
4.CB.20Ferrohögbomite-6N12S
[(Fe
2+
 
,Mg,Zn)
 
5
(Al,Ti,Fe
3+
 
)
 
12
O
 
23
(OH)]
 
6
4.CB.25Pseudorutile
Fe
 
2
Ti
 
3
O
 
9
4.CB.25Kleberite
FeTi
 
6
O
 
11
(OH)
 
5
4.CB.30Berdesinskiite
V
3+
2
TiO
 
5
4.CB.30Oxyvanite
V
3+
2
V
4+
 
O
 
5
4.CB.35Olkhonskite
(Cr,V)
 
2
Ti
 
3
O
 
9
4.CB.35Schreyerite
V
3+
2
Ti
 
3
O
 
9
4.CB.40Kamiokite
Fe
 
2
Mo
 
3
O
 
8
4.CB.40Nolanite
(V
3+
 
,Fe
3+
 
,Fe
2+
 
,Ti)
 
10
O
 
14
(OH)
 
2
4.CB.40Rinmanite
Zn
 
2
Sb
 
2
Mg
 
2
Fe
 
4
O
 
14
(OH)
 
2
4.CB.40Iseite
Mn
 
2
Mo
 
3
O
 
8
4.CB.40Majindeite
Mg
 
2
Mo
 
3
O
 
8
4.CB.45Claudetite
As
 
2
O
 
3
4.CB.45Stibioclaudetite
AsSbO
 
3
4.CB.50Arsenolite
As
 
2
O
 
3
4.CB.50Sénarmontite
Sb
 
2
O
 
3
4.CB.55Valentinite
Sb
 
2
O
 
3
4.CB.60Bismite
Bi
 
2
O
 
3
4.CB.65Sphaerobismoite
Bi
 
2
O
 
3
4.CB.70Sillénite
Bi
 
12
SiO
 
20
4.CB.75Kyzylkumite
Ti
 
2
V
3+
 
O
 
5
(OH)
4.CB.80Tietaiyangite
Fe
3+
4
Fe
2+
 
TiO
 
9
Related Minerals - Hey's Index Grouping:

- +
7.9.1Hongquiite
TiO
7.9.2Rutile
TiO
 
2
7.9.3Anatase
TiO
 
2
7.9.4Brookite
TiO
 
2
7.9.5Geikielite
MgTiO
 
3
7.9.6Perovskite
CaTiO
 
3
7.9.7Kassite
CaTi
 
2
O
 
4
(OH)
 
2
7.9.8Tausonite
SrTiO
 
3
7.9.9Crichtonite
(Sr,La,Ce,Y)(Ti,Fe
3+
 
,Mn)
 
21
O
 
38
7.9.10Lucasite-(Ce)
CeTi
 
2
(O,OH)
 
6
7.9.11Hibonite
(Ca,Ce)Al
 
12
O
 
19
7.9.12Yttrocrasite-(Y)
(Y,Th,Ca,U)(Ti,Fe)
 
2
(O,OH)
 
6
7.9.13Pyrophanite
Mn
2+
 
TiO
 
3
7.9.14Iwakiite
Mn(Fe,Mn)
 
2
O
 
4
7.9.15Ilmenite
Fe
2+
 
TiO
 
3
7.9.16Pseudobrookite
Fe
 
2
TiO
 
5
7.9.17Ulvöspinel
Fe
 
2
TiO
 
4
7.9.18Pseudorutile
Fe
 
2
Ti
 
3
O
 
9
7.9.19Freudenbergite
Na
 
2
(Ti,Fe)
 
8
O
 
16
7.9.20Kennedyite
MgFe
3+
2
Ti
 
3
O
 
10
7.9.22Högbomite
(Mg,Fe)
 
2
(Al,Ti)
 
5
O
 
10
7.9.23Qandilite
(Mg,Fe)
 
2
(Ti,Fe,Al)O
 
4
7.9.24Cafetite
(Ca,Mg)(Fe,Al)
 
2
Ti
 
4
O
 
12
· 4H
 
2
O
7.9.25Loveringite
(Ca,Ce,La)(Zr,Fe)(Mg,Fe)
 
2
(Ti,Fe,Cr,Al)
 
18
O
 
38
7.9.26Lindsleyite
(Ba,Sr)(Zr,Ca)(Fe,Mg)
 
2
(Ti,Cr,Fe)
 
18
O
 
38
7.9.27Priderite
K(Ti
4+
7
Fe
3+
 
)O
 
16
7.9.28Jeppeite
(K,Ba)
 
2
(Ti,Fe)
 
6
O
 
13
7.9.29Ankangite
Ba(Ti,V
3+
 
,Cr)
 
8
O
 
16
7.9.30Ecandrewsite
(Zn,Fe
2+
 
,Mn
2+
 
)TiO
 
3
7.9.31Landauite
NaMnZn
 
2
(Ti,Fe)
 
6
Ti
 
12
O
 
38

Other Names for Armalcolite

Other Languages:
German:Armalcolit
Russian:Армолколит
Simplified Chinese:低铁假板钛矿
镁铁钛矿
阿尔马科月球石
Spanish:Armalcolita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Armalcolite

Reference List:

- +
Anderson A.T., Bunch T.E, Cameron E.N, Haggerty S.E., Boyd F.R., Finger L.W., James O.B., Keil K., Prinz M., Ramdohr P. and El Goresy A. (1970) Armalcolite, a new mineral from the Apollo 11 samples. Geochimica et Cosmochimica Acta 34, Supplement 1, 55-63.

Lind, M. D. and Houseley, R. M. (1972): Crystallization studies of lunar igneous rocks: Crystal structure of synthetic armalcolite. Science 175, 521-523.

Haggerty, S. E. (1973): Ortho and para-armalcolite samples in Apollo 17. Nature 242, 123-125.

Lindsley, D. H., Kesson, S. E., Hartzman, M. J., and Cushman, M. K. (1974): The stability of armalcolite: Experimental studies in the system MgO-Fe-Ti-O. Proceedings of the 5th. Lunar Science Conference, Geochimica et Cosmochimica Acta 61, Supplement 1, 521-534.

Smyth, J. R. (1974): The crystal chemistry of armalcolite from Apollo 17. Earth and Planetary Science Letters 24, 262-270.

Wechsler, B. A. (1977): Cation distribution and high-temperature crystal chemistry of armalcolite. American Mineralogist 62, 913-920.

Pedersen, A. K. (1981): Armalcolite-bearing Fe-Ti oxide assemblages in graphite-equilibrated salic volcanic rocks with native iron from Disko, central west Greenland. Contributions to Mineralogy and Petrology 77, 307-324.

Bowles, J. F. W. (1988): Definition and range of composition of naturally occurring minerals with the pseudobrookite structure. American Mineralogist 73, 1377-1383.

Hayob, J. L. and Essene, E. J. (1995): Armalcolite in crustal paragneiss xenoliths, central Mexico. American Mineralogist 80, 810-822.

Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 22.

Internet Links for Armalcolite

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  • Localities for Armalcolite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Antarctica
     
    • Eastern Antarctica
      • Victoria Land
        • Allan Hills
    Makoto Kimura & Ahmed El Goresy (1989). Discovery of E-Chondrite Assemblages and Silica-Bearing Objects in ALH85085:- Link Between E- and C-Chondrites (Abstract). Abstracts and Program for the 52nd Annual Meeting of the Meteoritical Society. LPI Contribution 712, p. 112.
    Austria
     
    • Styria
      • Bad Radkersburg
        • Klöch
    Taucher, J. & Hollerer, C. E. (1998): Minerale eines Si- und Al-reichen Xenoliths aus dem Basaltsteinbruch von Klöch, Nördlicher Bruch, (Steiermark, Österreich). Mitt. naturwiss. Ver. Steiermark 128, 21-42.
    China
     
    • Shaanxi Province
      • Hanzhong Prefecture
        • Ningqiang Co.
    Lin, Y. T. & Kimura, M. (1996). Discovery of Complex Titanium Oxide Associations in a Plagioclase-Olivine Inclusion (POI) in the Ningqiang Carbonaceous Chondrite. Lunar and Planetary Science, vol. 27, pages 755-756. (1996).
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Liberec Region
    Kühn, P., Scharmová, M.: Manganový armalcolit a pseudorutil z uranonosných sedimentů severočeské křídové pánve u Stráže pod Ralskem. Bulletin mineralogicko-petrografického oddělení Národního muzea v Praze, 1999, roč. 7, s. 173-176.
    French Southern and Antarctic Lands
     
    Contrib. Mineral. Petrol., 122, 174-190 (1995)
    Germany
     
    • Bavaria
      • Swabia
        • Nördlingen
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    Greenland
     
    • Qaasuitsup
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    Pedersen, A.K. (1979) A shale buchite xenolith with Al-armalcolite and native iron in a lava from Asuk, Disko, central West Greenland. Contributions to Mineralogy and Petrology, 69, No. 1, 83-94
    Mexico
     
    • Chihuahua
      • Pueblito de Allende
    Brearley, A. J. & Jones, R. H. (1998). Chondritic Meteorites. In: Planetary Materials (Papike, J. J., Editor): Chapter 3, 398 pages. Mineralogical Society of America: Washington, DC, USA. (1998)
    • San Luis Potosí
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    Mongolia
     
    • Hovd Aimag (Khovd Aimag)
      • Altai Mts
    P.M. Kartashov data
    Oman
     
    • Dhofar Province (Al Janubiyah Province)
    Meteoritical Bulletin No. 86
    www.meteoriticalsociety.org/bulletin/mb87.pdf.
    The Meteoritical Bulletin, No. 88, 2004 JULY, Meteoritics & Planetary Science 39, Axxx–Axxx (2004)
    Romania
     
    • Caraş-Severin Co.
      • Banat Mts
        • Gătaia
    Seghedi I., Ntaflos T. 2006: G˘ataia lamproite (SW Romania). Mineralogia Polonica, vol. 29, 188-191
    Russia
     
    • Eastern-Siberian Region
      • Sakha Republic (Saha Republic; Yakutia)
    [World of Stones 12:49]
      • Taymyrskiy Autonomous Okrug
        • Taimyr Peninsula
          • Khatanga
            • Malaya Romanikha River
    P.M. Kartashov data
    • Urals Region
      • Southern Urals
        • Chelyabinsk Oblast'
          • Chelyabinsk coal basin
    Cesnokov, B., M. Kotrly, and T. Nisanbajev (1998): Brennende Abraumhalden und Aufschlüsse im Tscheljabinsker Kohlenbecken - eine reiche Mineralienküche. Mineralien-Welt, 9 (3), 54-63 (in German).
    Slovakia
     
    • Banská Bystrica Region
      • Banská Bystrica Co.
        • Brusno
    Uher, P. ,Černý, P., 1998 : Vzácnoprvková mineralizácia v granitových pegmatitoch Nízkych Tatier. Mineralia Slovaca, 30, 2,93 – 94
    South Africa
     
    • Free State Province
      • Xhariep District
        • Jagersfontein
    Minerals of South Africa
    • Northern Cape Province
      • Francis Baard District
        • Kimberley
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    Spain
     
    • Castile-La Mancha
      • Albacete
        • Hellín
          • Cancarix
    E. Salvioli-mariani et al. , Eur. J. Mineral. , 1996, 8, pp. 1027-1039.
    • Murcia
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
    The Moon
     
    • Descartes Highlands
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22; Dowty, E., Keil, K., & Prinz, M. (1974) Igneous rocks from Apollo 16 rake samples. In: Lunar Science Conference, 5th, Houston, Tex., March 18-22, 1974, Proceedings. Volume 2. (A75-39540 19-91) New York, Pergamon Press, Inc., 1974, p. 431-445.
    • Mare Tranquillitatis (Sea of Tranquility)
    Proc. Apollo 11 Lunar Sci.Conf.(1970) 1, 55-63
    • Taurus-Littrow Valley
    www.union.edu/PUBLIC/GEODEPT/COURSES/petrology/moon_rocks/70017.htm ; Longhi, J., Walker, D., Grove, T. L., Stolper, E. M., & Hays, J. F. (1974) The petrology of the Apollo 17 mare basalts. In: Lunar Science Conference, 5th, Houston, Tex., March 18-22, 1974, Proceedings. Volume 1. (A75-39540 19-91) New York, Pergamon Press, Inc., 1974, p. 447-469.
    USA
     
    • Montana
      • Garfield Co.
    AmMin 60:566; Journal of Petrology Volume 33 :3 Pages 505-520 1992
    • Texas
      • Uvalde Co.
        • Knippa
    R&M 66:3 pp 196-224
    • Utah
      • Piute Co.
    Mineralogical Magazine 1998 62 : 265-269
    • Wyoming
      • Sweetwater Co.
    http://gsa.confex.com/gsa/2002RM/finalprogram/abstract_33540.htm
    Zimbabwe
     
    • Masvingo
    J. W. Anthony et al.: Handbook of Mineralogy, Vol. 3 (1997), 22
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