Sterley        34.21°N, 101.39°W

Texas, USA

Found: 1950

Classification: Pallasite (Main group)

History: A single mass weighing 1724.8 grams, and displaying regmaglypts and some remnant fusion crust, was found ~1950 by a farmer while plowing. Several months later, the finder took the specimen to Texas Tech University where it was classified by a mineralogist Mr. Dennis as a " stony iron siderolite - variety pallasite".  Decades later, after watching a television show on meteorites, the son of the finder took the specimen to Dr. Laurence Garvie at the Center for Meteorite Studies, ASU for further study. The pallasite was later purchased by Ruben Garcia and Geoff Notkin.

Physical characteristics: Single, fragmental piece with a few patches of remnant fusion crust. Greenish olivine crystals protruding from the surface. Small area of farringtonite visible at the surface. Weathering is minor and restricted primarily to small areas at the edge of the stone.

Petrography: (L. Garvie, ASU). A 12 × 6 cm polished and etched slice shows (areal %): swathing kamacite 39.8, plessite 20.0, olivine 36.2, troilite 1.9, schreibersite 1.1, and farringtonite 0.9. Olivine grains are typically well rounded and <1 cm, though some are angular. Swathing kamacite, to 1-mm thick, well developed, some areas showing prominent Neumann bands. Many of the plessite fields show well-developed kamacite laths.

Geochemistry: (J. Wasson, UCLA; L. Garvie, ASU) Metal composition by INAA (mean of two analyses) Ni 117 mg/g; Co 5.75 mg/g, Cu 316 μg/g, Ga 18.5 μg/g, As 26.5 μg/g, Ir 0.076 μg/g, and Au 2.727 μg/g.  EMPA of 13 separate olivine grains gave Fa_17.5±0.1, FeO/MnO=54.6±4.7, Cr₂O₃=0.03±0.01, n=19.  Based on the elemental composition and the high olivine Fa content the meteorite appears to be unpaired with other known pallasites.

Classification: Main-group pallasite.

Specimens: 141 g at ASU.