Sacramento Wash 005                   34°44'48''N, 114°12'36''W

Mohave County, Arizona, United States

Find: 18 May, 2004

Iron (ungrouped, troilite-rich)

History: These samples were found in the vicinity of the Franconia H5 strewn field. Reportedly hundreds of pieces from this fall, the majority of which are under 1 g, have been found by a number of meteorite hunters as well.

Physical characteristics: The total mass of the two pieces is 52.3 g. A mass of 8.60 g was found by Pete Meyers on May 18, 2004 (UA2006), and a mass of 43.7 g was found by Jim Smaller on October 29, 2005 (UA2026). The surfaces of both samples are indistinguishable. No fusion crust is present, although bluish fusion crust with flow lines was observed on other samples that were studied. Both meteorites are reddish-brown, have rounded edges, mildly weathered surfaces, fresh interiors, and pits on the surface that are due to inclusions that were plucked out during atmospheric entry or weathering.

Petrography: (D. Schrader and D. Lauretta, UAz) The meteorites consist predominantly of Fe,Ni metal. Kamacite is the dominant phase, with taenite present as exsolution in the kamacite. Troilite (~19% of surface area) is present as elongate inclusions in the Fe,Ni metal, up to 2 mm long. Iron oxide surrounds portions of the troilite inclusions. Other minor phases include Ca phosphates, chromite, and rare metallic copper. A 2 mm silicate inclusion in UA2006 contains Fe,Ni metal, troilite, olivine, pyroxene, plagioclase, Ca phosphate, and chondrules (predominantly POP, but also CC) with apparent diameters of 0.13 mm to 0.35 mm.

Mineral compositions: (D. Schrader, D. Lauretta, K. Domanik, and D. Hill, UAz) (EMP at UAz) Kamacite, Ni = 6.9 ± 0.7, Co = 0.41 ± 0.03 [averages, wt%]). Taenite, Ni = 25.0 ± 4.8, Co = 0.14 ± 0.08 [averages, wt%]). Silicate inclusion: olivine, Fa_16.8-20.6 (average = Fa_17.5±0.9); low-Ca pyroxene Fs_14.4-19.9 (average = Fs_15.5±1.05); Wo_0.38-3.82 (average = Wo_1.22±0.71).

Classification: Iron (ungrouped, troilite-rich). Yucca’s [sic] metal and silicate inclusion share affinities to H-type material. Specimens: A total of 11.35 g is on deposit at UAz. Smaller holds the main mass.

Submitted by: D. Schrader, UAz.