Less than 0.5% of meteorites are from Mars. Martian meteorites are often referred to in the scientific literature as SNCs (after the type specimens Shergotty, Nakhla and Chassigny — cities in India, Egypt and France, where these meteorites were seen to fall). Among the three principal types of Martian meteorites, chassignites are the least common; less than 1% of all Martian meteorites are chassignites and only three chassignites are known. Chassignites consist mainly of olivine that formed within a magma chamber deep under the Martian surface. As the crystals grew, gravity caused them to settle toward the bottom of the chamber. A tremendously energetic asteroid impact was required to blast these subterranean Martian mantle samples into interplanetary space.

The most challenging chassignite to acquire is a sample of Chassigny itself. Chassigny fell mid-morning on October 3, 1815 and curiously, 147 years later to the day, the Martian shergottite Zagami (see lot 36) fell in Nigeria. They also fell at approximately the same time of day and both events occurred on what is uncannily nearly the same line of longitude. This gave rise to a theory espoused by Dr. Allan Treiman of NASA’s Johnson Space Center of the existence of a stream of Martian meteoroids that periodically intersects Earth’s orbit.

Of the four kilograms of Chassigny documented to have been recovered in 1815, less than one kilogram is preserved. This diminutive cut fragment exhibits a distinctive green hue. The cut and polished face reveals grains of olivine and pyroxene. A cut mark is on the reverse in this offering of one of the Holy Grails in the field of meteoritics — a specimen of Chassigny, an exotic sample of the mantle of the planet Mars. Modern cutting.

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.

5 x 9 x 6mm (0.2 x 0.3 x 0.2 in.) and 0.791g (4 carats)