Pallasite, PMG (main-group)
standby for mount vernon photo
Found ~1868, recognized 1902
36° 56' N., 87° 24' W.

A mass of 351 pounds was found on the farm of Capt. S. Fruit, about 7 miles northeast of Hopkinsville, Kentucky, but it was not recognized as a meteorite until 1902. During the intervening years, the owner had used the meteorite as a boot scraper, and had finally sent a sample to E. Ulrich, of the U.S. Geological Survey, but only when the increasing price of zinc and lead made him curious about its true nature. Mr. Ulrich subsequently acquired the specimen for the U.S. National Museum. The Catalogue of Meteorites fourth edition lists Mount Vernon as a fall during the year 1868, but this claim is in question. Only Marjalahti, Omolon, and Zaisho are undisputed pallasite falls.

An extended terrestrial exposure has led to significant oxidation of the exterior of the mass, which measured 33 × 36 × 55 cm when acquired by the museum. Mount Vernon is composed of unusually large and compact blebs of olivine ranging from 5 mm to 25 mm in diameter with only a minimal network of FeNi-metal containing thin veinlets of phosphide. It was estimated by E. R. D. Scott (1977) that the size of the largest olivine grains in Mount Vernon reached a size of at least 30 cm.

This pallasite is much less stable to terrestrial oxidation than many others. The specimen pictured above is a 24.5 g partial slice, which unfortunately has experienced further deterioration during its residence in humid Florida. The photo below shows a 1,507 g partial slice, which was acquired by the owner from the Robert Haag Collection, previously obtained from the United States National Museum, Smithsonian Institution. Synopses of several different proposed formation histories of the main-group pallasites can be found on the Imilac page.

standby for mount vernon photo
Photo courtesy of the Dr. J. Piatek Collection