Sample No.: ALH84004

Location: Allan Hills

Weight (g): 9000.0

Field No.: 2505

Dimensions (cm): 21 x 16 x 16

Meteorite Type: H4 Chondrite

Macroscopic Description: Carol Schwarz

Slightly weathered fusion crust covers this large specimen. Deep regmaglypts are abundant as are deep crevasses that are filled in with fusion crust. Some salt deposit has formed. The interior is red-brown to dark grayish with some areas of light gray matrix visible.

Thin Section (,4) Description: Glenn MacPherson

This chondrite is heavily stained by iron oxide, indicating that it has experienced a moderate degree of terrestrial weathering. Well-defined chondrules and clasts, up to 3.5 mm in diameter, are very closely packed. No isotropic glass is preserved anywhere, but devitrified glass is common. Olivine is uniformly Fa17-18 in composition. The pyroxene is commonly monoclinic, and is Fs16-19. Coarse kamacite, troilite, and taenite are abundant, with the metal phases considerably in excess of the sulfide. Chromite is accessory. In one portion of the thin section there is abundant black interstitial material that consists of veins, stringers, patches, and tiny globules of metal and sulfide in a microcrystalline intergrowth. These are probably shock veins. The silicates in this region show some evidence of brecciation and, locally, granulation. This is an H4 chondrite.