Apizaco        19.42°N, 98.13°W

Tlaxcala, Mexico

Find: 1961

Classification: Iron meteorite (IIIAB)

History: The meteorite was found by Louis Giraud in about 1961 at the edge of a maize field in the Tlaxcala province of Mexico. Louis and his father Marcel were quail hunting. The exact location is no longer known; they frequently drove from Mexico City to this field and woods region to hunt quail, but the location varied from trip to trip. Apizaco is a small city within about 10 km of the discovery location. The meteorite has been in the possession of Marcel and Louis Giraud since it was found.

Petrography: The meteorite is a medium octahedrite with a bandwidth of ~1.05 mm. It has no heat altered zone and fresh surfaces rust relatively quickly. It has a 0.2 mm oxide filled crack that crosses 80% of the cut face. A low-resolution microscopic study shows a well-preserved structure with no evidence of cosmic reheating. There are numerous small (typically 0.7-1.5 mm) dark plessite fields. No FeS was observed. Schreibersite is rare, but in one region several elongated grains (the largest 0.6-3 mm) are quasi parallel suggesting that this was a region with some trapped melt. Fine (~0.02 mm) schreibersite lamellae are found in rare kamacite intersections.

Geochemistry: Composition: Co, 5.25 mg/g; Ni, 85.5 mg/g; Ga, 21.4 μg/g; Ge,<60 μg/g; As, 9.35 μg/g Ir, 0.322 μg/g; and Au, 1.174 μg/g.

Classification: The meteorite is a normal member of group IIIAB.

Specimens: The nearest compositional relatives are Seneca Falls (New York) and Sierra Sandon (Chile) which are obviously not part of the same fall event. The Mexican meteorite Asarco Mexicana, for which geographic coordinates are not known, has 15% lower As and Ir contents and 10% lower Au content and is very unlikely to be part of the same fall.