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CategoryNative mineral alloy
(repeating unit)
Strunz classification1.XX.00
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m)
Space groupP63/mmc
Unit cella = 2.7506, c = 4.4318 [Å]
V = 29.04 Å3, Z = 2
Crystal habitInclusions and microscopic crystals
Specific gravity11.90 (calculated)

Hexamolybdenum, is a molybdenum dominant alloy discovered during a nanomineralogy investigation of the Allende meteorite.[3] Hexamolybdenum was discovered in a small ultrarefractory inclusion within the Allende meteorite.[3] This inclusion has been named ACM-1.[3] Hexamolybdenum is hexagonal, with a calculated density of 11.90 g/cm3.[3] The new mineral was found along with allendeite.[3] These minerals, are believed to demonstrate conditions during the early stages of the Solar System, as is the case with many CV3 carbonaceous chondrites such as the Allende meteorite.[3] Hexamolybdenum lies on a continuum of high-temperature alloys that are found in meteorites and allows a link between osmium, ruthenium, and iron rich meteoritic alloys.[3] The name hexamolybdenum refers to the crystal symmetry (primitive hexagonal) and the molybdenum rich composition.[3] The Allende meteorite fell in 1969 near Pueblito de Allende, Chihuahua, Mexico.[3]


Hexamolybdenum was found as nano-crystals in an ultrarefractory inclusion in the Allende meteorite.[3] The Allende meteorite has shown to be full of new minerals, after nearly forty years it has produced one in ten of the now known minerals in meteorites.[3] This CV3 carbonaceous chondrite was the largest ever recovered on earth and is referred to as the best-studied meteorite in history.[3] The inclusion has only been viewed via electron microscopy.[3] The hexamolybdenum specimen was lost during an attempted ion probe analysis of a bordering grain.[3] Other specimens can be found, however, in the Smithsonian Institution's National Museum of Natural History Allende section USNM 3509HC12 and in section USNM 7590 of NWA 1934, another VC3 chondrite.[3]

It has also been reported from the NWA 1934 CV3 carbonaceous chondrite meteorite from the Erfoud region of Morocco and in the Danubian placer of Straubing, Bavaria.[1]

Chemical composition[edit]

Hexamolybdenum is an (molybdenum, ruthenium, iron, iridium, osmium) alloy.[3]


Color, streak, luster, hardness, tenacity, cleavage, fracture, density, and refractive index could not be observed because the grain size was too small and the section bearing the mineral was optically thick.[3]

See also[edit]


  1. ^ a b Mindat.org
  2. ^ Webmineral data
  3. ^ a b c d e f g h i j k l m n o p q r Beckett, John R.; Rossman, George R. (2014). "Allendeite (Sc3Zr4O12 and hexamolybdenum (Mo, Ru, Fe), two new minerals from an ultrarefractory inclusion from the Allende meteorite". American Mineralogist. 99: 654–666. Bibcode:2014AmMin..99..654M. doi:10.2138/am.2014.4667.