The Yamato 691 (abbreviated Y-691) is a 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] In 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] This meteorite is a stony enstatite chondrite.