armalcolite
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Armalcolite () is a titanium-rich mineral with the chemical formula (Mg,Fe2+)Ti2O5. It was first found at Tranquility Base on the Moon in 1969 during the Apollo 11 mission, and is named for Armstrong, Aldrin and Collins, the three Apollo 11 astronauts. Together with tranquillityite and pyroxferroite, it is one of three new minerals that were discovered on the Moon. Armalcolite was later identified at various locations on Earth and has been synthesized in the laboratory. (Tranquillityite and pyroxferroite were also later found at various locations on Earth). The synthesis requires low pressures
Key facts
- Mineral.name
- Armalcolite
- Mineral.category
- Titanium mineral
- Mineral.image
- Armalcolite - Wat Lu Mine, Mogok, Myanmar.jpg
- Mineral.caption
- Armalcolite from Myanmar (grain size 5 mm)
- Mineral.formula
- (Mg,Fe2+)Ti2O5
- Mineral.IMAsymbol
- Arm
- Mineral.strunz
- 4.CB.15
- Mineral.system
- Orthorhombic
- Mineral.class
- Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
- Mineral.symmetry
- Bbmm
- Mineral.unit cell
- a = 9.743(30) b = 10.023(20) c = 3.738(30) [Å], Z = 5
- Mineral.color
- Gray to tan in reflection, opaque
- Mineral.mohs
- <5
- Mineral.luster
- Metallic
- Mineral.opticalprop
- Biaxial
- Mineral.gravity
- 4.64 g/cm3 (measured)
via Wikipedia infobox
~8 min read
Encyclopedic overview
6 sectionsContents
- Occurrence
- Synthesis
- Properties
- See also
- References
- External links
Armalcolite () is a titanium-rich mineral with the chemical formula (Mg,Fe2+)Ti2O5. It was first found at Tranquility Base on the Moon in 1969 during the Apollo 11 mission, and is named for Armstrong, Aldrin and Collins, the three Apollo 11 astronauts. Together with tranquillityite and pyroxferroite, it is one of three new minerals that were discovered on the Moon. Armalcolite was later identified at various locations on Earth and has been synthesized in the laboratory. (Tranquillityite and pyroxferroite were also later found at various locations on Earth). The synthesis requires low pressures, high temperatures and rapid quenching from about 1,000 °C to the ambient temperature. Armalcolite breaks down to a mixture of magnesium-rich ilmenite and rutile at temperatures below 1,000 °C, but the conversion slows down with cooling. Because of this quenching requirement, armalcolite is relatively rare and is usually found in association with ilmenite and rutile, among other minerals.
==Occurrence== thumb|left|The Apollo 11 crew, after whom Armalcolite is named. Left to right are [[Neil Armstrong, Michael Collins, and Buzz Aldrin.]]
Excerpted from Wikipedia’s “armalcolite” article, available under the CC BY-SA 4.0 licence.