Willow Wash                         35°22’24.88’’N, 115°20’’37.95’’W

San Bernardino County, CA, USA

Find: 14 September 2006

Ordinary chondrite (H3.5, breccia)

History: The stone was found by Steve Humeston in an area covered with sand, scattered rocks and sparse native vegetation.

Physical characteristics: A single stone of 552 g was recovered. It was completely covered with fusion crust.

Petrography: (A. Rubin, UCLA) Chondrule outlines are well defined; there has been little integration between chondrules and matrix. Some chondrules contain glassy mesostases. The rock has been shocked; olivine grains exhibit undulose extinction under crossed polarizers in the petrographic microscope; the olivine grains contain planar fractures in their crystal structure caused by shock. The rock is moderately weathered; between 20% and 60% of the metal grains have been at least somewhat oxidized. The rock is also a breccia. It contains a clast that has experienced more significant shock than the host; much of the metal and sulfide in the clast was melted and mobilized by shock. The boundary between the clast and the host is sharp.

Mineral compositions and geochemistry: The rock is unequilibrated with a large range in olivine composition (Fa 12.8–30.9 mol%, n = 13). The mean Fa content is 20.9 ± 4.7 mol% and it has a percent mean deviation (PMD for Fa) of 17.2.

Classification: Ordinary chondrite (H3.5 breccia), S3, W2.

Type specimens: A total sample mass of 30 g is on deposit at UCLA. The remaining mass of 472 g is in the possession of the finder.