Imilac Pallasite 190 g
Imilac (Pallasite main group, stony-iron, angulare olivine shape) || found 1822, Atacam desert, Chile, 920 kilograms total weight.
Numerous masses, with individuals up to 450lb, were found in a valley to the SW of Imilac, T.Allan, Trans. Roy. Soc. Edinburgh, 1831, 11, p.223, L.Fletcher, Min. Mag., 1889, 8, p.243. The specimen found in 1879 at Campo del Puchara, Argentina, was probably carried from Imilac, E.Cohen, Neues Jahrb. Min., 1887, 2, p.45, M.H.Hey, Cat. Met., 1966, p.212. Track study of olivine, L.L.Kashkarov et al, Meteoritika, 1972, 31, p.157. Coordinates, transported masses, strewnfield, craters, metal deformation, V.F.Buchwald, Handbook of Iron Meteorites, Univ. of California, 1975, p.1393.
Pallasites are easily the most beautiful meteorites, especially when cut and polished. The pallasites consist of olivine crystals that may be as large as 1 cm across embedded in a Fe-Ni alloy matrix with minor troilite (FeS). When etched, the metal phase may exhibit a Widmanstatten pattern. Pallasites are considered to be the result of mixing between solid silicate mantle and liquid metal core at the core-mantle boundary of a fully differentiated parent body. This mineralogy is consistent with complete differentiation of a chondritic asteroid, leaving only olivine in the silicate residue at the core-mantle boundary.