Armalcolite
A valid IMA mineral species
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About Armalcolite
Formula:
(Mg,Fe2+)Ti2O5
Colour:
Grey
Lustre:
Metallic
Hardness:
5
Specific Gravity:
4.94
Crystal System:
Orthorhombic
Member of:
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, d. 2012), Edwin Eugene ALdrin (b. 1930) and Michael COLlins (b. 1930), the Apollo 11 astronauts who collected the type samples.
Unique Identifiers
Mindat ID:
341
Long-form identifier:
mindat:1:1:341:0
GUID
(UUID V4):
(UUID V4):
b4349252-d46f-4b44-a7ef-ea886651fb02
IMA Classification of Armalcolite
Approved
First published:
1970
Classification of Armalcolite
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
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
7.7.1.2
7 : MULTIPLE OXIDES
7 : AB2X5
7 : MULTIPLE OXIDES
7 : AB2X5
7.9.21
7 : Oxides and Hydroxides
9 : Oxides of Ti
7 : Oxides and Hydroxides
9 : Oxides of Ti
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Symbol | Source | Reference |
---|---|---|
Arm | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Arm | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
Physical Properties of Armalcolite
Metallic
Transparency:
Opaque
Colour:
Grey
Hardness:
5 on Mohs scale
Density:
4.94 g/cm3 (Measured) 4.64 g/cm3 (Calculated)
Optical Data of Armalcolite
Type:
Biaxial
Anisotropism:
Strong, pale grey to dark bluish gray
Reflectivity:
Wavelength | R1 | R2 |
---|---|---|
450 nm | 14.1% | 15.2% |
470 nm | 14.0% | 15.0% |
500 nm | 13.8% | 14.7% |
520 nm | 13.7% | 14.5% |
546 nm | 13.4% | 14.4% |
586 nm | 13.3% | 14.3% |
620 nm | 13.2% | 14.2% |
640 nm | 13.0% | 14.1% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 15.2%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Grey to tan
Pleochroism:
Visible
Chemistry of Armalcolite
Mindat Formula:
(Mg,Fe2+)Ti2O5
Elements listed:
Crystallography of Armalcolite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 9.743 Å, b = 10.023 Å, c = 3.738 Å
Ratio:
a:b:c = 0.972 : 1 : 0.373
Unit Cell V:
365.03 ų (Calculated from Unit Cell)
Z:
2
Comment:
Space Group: Bbmm
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
---|---|---|---|---|---|---|---|
0000590 | Armalcolite | Wechsler B A (1977) Cation distribution and high-temperature crystal chemistry of armalcolite American Mineralogist 62 913-920 | 1977 | 0 | 297 | ||
0000591 | Armalcolite | Wechsler B A (1977) Cation distribution and high-temperature crystal chemistry of armalcolite American Mineralogist 62 913-920 | 1977 | 0 | 297 | ||
0000592 | Armalcolite | Wechsler B A (1977) Cation distribution and high-temperature crystal chemistry of armalcolite American Mineralogist 62 913-920 | 1977 | 0 | 1373 | ||
0000593 | Armalcolite | Wechsler B A (1977) Cation distribution and high-temperature crystal chemistry of armalcolite American Mineralogist 62 913-920 | 1977 | 0 | 297 | ||
0000594 | Armalcolite | Wechsler B A (1977) Cation distribution and high-temperature crystal chemistry of armalcolite American Mineralogist 62 913-920 | 1977 | 0 | 673 | ||
0009835 | Armalcolite | Wechsler B A, Von Dreele R B (1989) Structure refinements of Mg2TiO4, MgTiO3 and MgTi2O5 by time-of-flight neutron powder diffraction Acta Crystallographica B45 542-549 | 1989 | synthetic | 0 | 293 | |
0009836 | Armalcolite | Wechsler B A, Von Dreele R B (1989) Structure refinements of Mg2TiO4, MgTiO3 and MgTi2O5 by time-of-flight neutron powder diffraction Acta Crystallographica B45 542-549 | 1989 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
3.468 Å | (100) |
1.958 Å | (80) |
2.763 Å | (25) |
2.454 Å | (25) |
2.235 Å | (15) |
2.199 Å | (15) |
2.414 Å | (10) |
Comments:
Recorded on type material
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 1: Primary nebular phases | 4.567-4.561 |
4 : Primary chondrule phases | 4.566–4.561 |
Stage 3a: Earth’s earliest Hadean crust | >4.50 |
7 : Ultramafic igneous rocks | |
Near-surface Processes | |
30 : Terrestrial impact minerals | |
High-𝑇 alteration and/or metamorphism | |
31 : Thermally altered carbonate, phosphate, and iron formations | |
Stage 4b: Highly evolved igneous rocks | >3.0 |
35 : Ultra-alkali and agpaitic igneous rocks | |
Stage 5: Initiation of plate tectonics | <3.5-2.5 |
41 : Mantle metasomatism |
Geological Setting:
in salic volcanics; in ultramafic rocks, lamproites and kimberlites; in terrestrial impact craters; in inclusions in carbonaceous chondrites; rarely in granite pegmatites
Type Occurrence of Armalcolite
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
Geological Setting of Type Material:
in Ti-rich basalt and microbreccias of lunar samples, formed at low pressures and high temperatures
Reference:
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., El Goresy, A. (1970) Armalcolite, a new mineral from the Apollo 11 samples. Geochimica et Cosmochimica Acta: 34: Supplement 1: 55-63.
Other Language Names for Armalcolite
Relationship of Armalcolite to other Species
Member of:
Other Members of this group:
Ferropseudobrookite | Fe2+Ti2O5 | Orth. mmm (2/m 2/m 2/m) : Cmcm |
Griffinite | Al2TiO5 | Orth. mmm (2/m 2/m 2/m) : Cmcm |
Pseudobrookite | Fe2TiO5 | Orth. mmm (2/m 2/m 2/m) |
Sassite | Ti3+2Ti4+O5 | Orth. mmm (2/m 2/m 2/m) : Cmcm |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
2 photos of Armalcolite associated with Tetraferriphlogopite | KMg3(Fe3+Si3O10)(OH,F)2 |
2 photos of Armalcolite associated with Sanidine | K(AlSi3O8) |
1 photo of Armalcolite associated with Pseudobrookite | Fe2TiO5 |
Related Minerals - Strunz-mindat Grouping
4.CB. | Ferrohögbomite-2N2S | [(Fe2+,Mg,Zn,Al)3(Al,Ti,Fe3+)8O15(OH)]2 |
4.CB. | Magnesiohögbomite-6N12S | Mg5Al11TiO23(OH) |
4.CB. | Zhenruite | (MoO3)2 · H2O |
4.CB. | Pengite | (Pb8Sb3+3)Σ11Sb5+9O35 |
4.CB. | Virgilluethite | MoO3 · H2O |
4.CB.05 | Brizziite | NaSb5+O3 |
4.CB.05 | Corundum | Al2O3 |
4.CB.05 | Ecandrewsite | (Zn,Fe2+,Mn2+)TiO3 |
4.CB.05 | Eskolaite | Cr2O3 |
4.CB.05 | Geikielite | MgTiO3 |
4.CB.05 | Hematite | Fe2O3 |
4.CB.05 | Ilmenite | Fe2+TiO3 |
4.CB.05 | Karelianite | V3+2O3 |
4.CB.05 | Melanostibite | Mn2+2Fe3+Sb5+O6 |
4.CB.05 | Pyrophanite | Mn2+TiO3 |
4.CB.05 | Akimotoite | (Mg,Fe2+)SiO3 |
4.CB.05 | Auroantimonate | AuSbO3 |
4.CB.05 | UM1998-11-O-AuHSb | Au+2Sb3+O2(OH) |
4.CB.05 | Tistarite | Ti3+2O3 |
4.CB.05 | Unnamed (Fe-Cr Oxide) | FeCrO3 |
4.CB.05 | Hemleyite | (Fe2+0.48Mg0.37Ca0.04Na0.04Mn2+0.03Al0.03Cr3+0.01)sum=1.00Si1.00O3 |
4.CB.10 | Avicennite | Tl2O3 |
4.CB.10 | Bixbyite-(Mn) | Mn3+2O3 |
4.CB.10 | Bixbyite-(Fe) | (Fe,Mn)2O3 |
4.CB.15 | Sassite | Ti3+2Ti4+O5 |
4.CB.15 | Pseudobrookite | Fe2TiO5 |
4.CB.15 | Ferropseudobrookite | Fe2+Ti2O5 |
4.CB.15 | Griffinite | Al2TiO5 |
4.CB.15 | Pseudobrookite Group | |
4.CB.20 | Zincohögbomite-2N2S | [(Zn,Al,Fe2+)3(Al,Fe3+,Ti)8O15(OH)]2 |
4.CB.20 | Zincohögbomite-2N6S | [(Zn,Mg)7(Al,Fe3+,Ti)16O31(OH)]2 |
4.CB.20 | Magnesiohögbomite-6N6S | [(Mg,Fe2+)3(Al,Ti,Fe3+)8O15(OH)]6 |
4.CB.20 | Magnesiohögbomite-2N3S | [(Mg,Fe2+,Zn)4(Al,Ti,Fe3+)10O19(OH)]2 |
4.CB.20 | Magnesiohögbomite-2N2S | [(Mg,Fe2+)3[Al7(Ti,Fe3+)]O15(OH)]2 |
4.CB.20 | Ferrohögbomite-6N12S | [(Fe2+,Mg,Zn)5(Al,Ti,Fe3+)12O23(OH)]6 |
4.CB.20 | Magnesiohögbomite-2N4S | (Mg8.43Fe2+1.57)sum=10Al22Ti4+2O46(OH)2 |
4.CB.20 | Magnesiobeltrandoite-2N3S | (Mg6Al2)(Al18Fe3+2)O38(OH)2 |
4.CB.20 | Zincovelesite-6N6S | Zn3(Fe3+,Mn3+,Al,Ti)8O15(OH) |
4.CB.25 | Pseudorutile | Fe2Ti3O9 |
4.CB.25 | Kleberite | FeTi6O11(OH)5 |
4.CB.30 | Berdesinskiite | V3+2TiO5 |
4.CB.30 | Oxyvanite | V3+2V4+O5 |
4.CB.30 | Kaitianite | Ti3+2Ti4+O5 |
4.CB.35 | Olkhonskite | (Cr,V)2Ti3O9 |
4.CB.35 | Schreyerite | V3+2Ti3O9 |
4.CB.35 | Machiite | Al2Ti3O9 |
4.CB.35 | Vestaite | (Ti4+Fe2+)Ti4+3O9 |
4.CB.40 | Kamiokite | Fe2Mo3O8 |
4.CB.40 | Nolanite | V3+8Fe3+2O14(OH)2 |
4.CB.40 | Rinmanite | Zn2Sb2Mg2Fe4O14(OH)2 |
4.CB.40 | Iseite | Mn2Mo3O8 |
4.CB.40 | Majindeite | Mg2Mo3O8 |
4.CB.45 | Claudetite | As2O3 |
4.CB.45 | Stibioclaudetite | AsSbO3 |
4.CB.50 | Arsenolite | As2O3 |
4.CB.50 | Senarmontite | Sb2O3 |
4.CB.55 | Valentinite | Sb2O3 |
4.CB.60 | Bismite | Bi2O3 |
4.CB.65 | Sphaerobismoite | Bi2O3 |
4.CB.70 | Sillénite | Bi12SiO20 |
4.CB.75 | Kyzylkumite | V3+Ti2O5(OH) |
4.CB.80 | Tietaiyangite | Fe3+4Fe2+TiO9 |
4.CB.85 | Liuite | FeTiO3 |
4.CB.90 | Luogufengite | Fe2O3 |
4.CB.95 | Wangdaodeite | FeTiO3 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Armalcolite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Armalcolite
mindat.org URL:
https://www.mindat.org/min-341.html
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References for Armalcolite
Reference List:
Localities for Armalcolite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Antarctica | |
| Makoto Kimura & Ahmed El Goresy (1989) |
Argentina | |
| Tassara et al. (2017) |
Australia | |
| Ikeda et al. (1996) +1 other reference |
Austria | |
| Taucher et al. (1998) |
Brazil | |
| Kogarko et al. (2001) |
Canada | |
| Roach et al. (1998) |
China | |
| Lin et al. (1996) |
Czech Republic | |
| Kühn +5 other references |
France | |
| Contrib. Mineral. Petrol. et al. (1995) +1 other reference |
Germany | |
| Neumair et al. (2016) |
J. W. Anthony et al.: Handbook of Mineralogy (1997) | |
| Schäfer (2021) |
Greenland | |
| J. W. Anthony et al.: Handbook of Mineralogy (1997) |
Pedersen (1979) | |
Mexico | |
| Brearley et al. (1998) |
| J. W. Anthony et al.: Handbook of Mineralogy (1997) |
Mongolia | |
| Pavel.M. Kartashov (n.d.) |
Oman | |
| Meteoritical Bulletin No. 86 |
Russell et al. (2003) | |
The Meteoritical Bulletin et al. (2004) | |
Romania | |
| Seghedi I. (SW Romania) |
Russia | |
| Cesnokov et al. (1998) |
| Sharygin et al. (2010) |
| Pavel.M. Kartashov (n.d.) |
[World of Stones 12:49] | |
| Litasov et al. (2017) +1 other reference |
6th orogenic lherzolite conference 2014 ... | |
Serbia | |
| Kostić +3 other references |
Slovakia | |
| Uher |
South Africa | |
| Cairncross et al. (1995) |
| MCDONALD I. (2005) |
| J. W. Anthony et al.: Handbook of Mineralogy (1997) |
J. W. Anthony et al.: Handbook of Mineralogy (1997) | |
Spain | |
| Prinz et al. (1983, March) |
| Venturelli et al. (1984) +2 other references |
E. Salvioli-mariani et al. | |
| Joan Rosell |
Joan Rosell SEM-EDS analysis | |
| J. W. Anthony et al.: Handbook of Mineralogy (1997) |
USA | |
| Velde (1975) +1 other reference |
| Smith (1991) |
| Mineralogical Magazine 1998 62 : 265-269 |
| Zach Capel |
| gsa.confex.com (n.d.) |
Zimbabwe | |
| J. W. Anthony et al.: Handbook of Mineralogy (1997) |
The Moon | |
| Dowty et al. (1974) +1 other reference |
| Anderson et al. (1970) |
| ... +1 other reference |
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Ophite outcrop, Casterner de les Olles, Tremp, El Pallars Jussà, Lleida, Catalonia, Spain