Yamato 691

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Yamato 691
ClassEnstatite chondrite
CompositionPl(An32-75), En99.2Wo-0.3, tro., nini., oldh., perr., schr., metal(2.2-2.5%Ni, 0.16-0.22%Co)[1]
RegionQueen Fabiola Mountains (Yamato Mountains)
Coordinates71°50′S 36°15′E / 71.833°S 36.250°E / -71.833; 36.250Coordinates: 71°50′S 36°15′E / 71.833°S 36.250°E / -71.833; 36.250[2]
Observed fallNo
Fall date4.5 billion years ago
Found dateDecember 21, 1969
TKW715 grams (1.576 lb)

The Yamato 691 (abbreviated Y-691) is the 4.5 billion year old chondrite meteorite discovered by members of the Japanese Antarctic Research Expedition[3] on the blue ice field of the Queen Fabiola Mountains (Yamato Mountains) in Antarctica, on December 21, 1969.[2]


Yamato 691 was one among 9 meteorite specimens identified by the Japanese Expedition Team in 1969. It was later studied at the Max Planck Institute for Chemistry, Mainz, Germany.[4]

On April 2011, NASA and co-researchers from the United States, South Korea and Japan have found a new mineral named "Wassonite" in Yamato 691.[5]

Composition and classification[edit]

This meteorite is a stony enstatite chondrite. Minerals reported from the meteorite include:[6]

See also[edit]


  1. ^ "Catalog of Antarctic Meteorites" (PDF). Tokyo: National Institute of Polar Research. 2000. Retrieved 2011-04-07.
  2. ^ a b "Yamato 691". The Meteoritical Society. Retrieved 2011-04-07.
  3. ^ Dwayne C. Brown; William Jeffs (2011-04-05). "Scientists Find New Type Of Mineral In Historic Meteorite". NASA. Retrieved 2011-04-07.
  4. ^ Clarke, R. S. Jr. (1974). "Meteoritical Bulletin, No. 52". Meteoritics. 9: 118. Bibcode:1974Metic...9..101C. Retrieved 2011-04-07.
  5. ^ Bryner, Jeanna (2011-04-06). "4.5-Billion-Year-Old Antarctic Meteorite Yields New Mineral". LiveScience. Retrieved 2011-04-07.
  6. ^ "Yamato 691 Meteorite, Queen Fabiola Mountains (Yamato Mountains), Antarctica". Retrieved 2011-04-07.

External links[edit]