Northwest Africa 11197 (NWA 11197)

(Northwest Africa)

Purchased: 2016

Classification: Primitive achondrite (Lodranite)

History: Two stones weighing 186 and 1424 g were found in Morocco and subsequently purchased in 2015. J. Donald Cline and John Sinclair acquired the samples from a meteorite prospector at the Tucson Gem and Mineral Show in February 2016.

Physical characteristics: Sample has an irregular, weakly conical shape. Orange caliche covers 75% of the stone, which may have originally been buried. In small areas, a dark-colored relict fusion crust is visible underneath the caliche. The other side of the stone is crystalline and composed of dark gray and green interlocking crystals.

Petrography: Description and classification (A. Love, App): Sample is a protogranular breccia of up to 4 cm long clasts and related debris composed of 1.5-3.5 mm, finely exsolved Ca-pyroxene and olivine. Accessory minerals are: FeNi metal, chromite and troilite. Olivine occurs as grains and melt inclusions within cpx. Some areas of the sample contain symplectic intergrowths olivine and chromite.

Geochemistry: (A.Love, App) Fa_11.6±0.2, Fe/Mn=46.0 N=8; Ca pyroxene Fs_4.7±0.2Wo_44.0±1.7, N=10.

Classification: Primitive achondrite (lodranite). Texture, grain size and mineral compositions indicate sample is a lodranite breccia.

Specimens: PARI holds the 155.48 g and 1424 g masses. A 20.87 g type specimen composed of 2 slices, several small fragments and one polished thin section are on deposit at App.