Among the rarest substances on Earth, every single bit of the Moon on Earth could fit in the back of a small pick-up. This includes the nearly 400 kilograms of Moon rocks returned by the Apollo astronauts as well as all lunar meteorites — pieces of the Moon ejected off the lunar surface following asteroid impacts. (Nearly all of the craters on the Moon are the result of such impacts.) Making the Moon all the more rare still is that a significant fraction of this material is held by museums, research centers and governments.

Moon rocks are identified by a variety of parameters including their textural, mineralogical, chemical, and isotopic signatures. The classic character of a feldspathic lunar breccia is seen in this example: white anorthite suspended in a charcoal lunar regolith “cemented’ together as part of a melt that solidified. The primary minerals in this sample are anorthite, olivine, pigeonite, augite, fayalite, silica, ilmenite and kamacite. The brecciation is the result of the ongoing bombardment of the Moon’s surface by asteroid impacts prior to the collision responsible for launching this Moon rock to Earth. Some lunar samples brought to Earth by the Apollo missions are extremely similar to suspected lunar meteorites and NWA 12691 — the 12,691^st distinct numbered specimen to be recovered, classified and considered for publication in the Meteorite Bulletin, the catalogue raisonnée of meteorites — is one such example. This specimen is cut and polished on two sides; its natural exterior surface was wrought due to exposure to the elements during its centuries-long residency in the Sahara Desert. Modern cutting.

The analysis of NWA 12691was led by Dr. Anthony Irving, whose findings underwent peer review by the Nomenclature Committee of the Meteoritical Society. The analysis and classification were published in the 108th edition of the Meteoritical Bulletin, the official registry of meteorites.

Christie's would like to thank Dr. Alan E. Rubin at the Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles for his assistance in preparing this catalogue.
57 x 55 x 29mm (2.25 x 2 x 1 in.) and 136 grams (0.3 lbs)