Adrar 017        27°7.41' N, 0°47.15' E

Adrar, Algeria

Purchased: 2025 Apr

Classification: Lunar meteorite (troctolitic anorthosite)

Physical characteristics: The meteorite is a large 18.2 kg gray stone.

Petrography: The meteorite exhibits a brecciated texture dominated by cm-size grayish-greenish clasts in a dark gray matrix. Melt pockets within anothositic matrix can also be found. Two analysed fragments chosen from the most common lithologies, one grey-greenish coloured and one dark grey corresponding to the ground-mass, have both a troctolitic anorthosite composition based on modal mineralogy (through SEM-BSE images on the grey-greenish fragment) and calculated normative composition (through SEM-EDS elemental maps on the darker fragment), with the following mineral abundances: plagioclase 86.9 vol%, olivine 8.0 vol%, pyroxene 5.2 vol% (for the darker clast) and plagioclase 82.0 vol%, olivine 11.0 vol%, pyroxene 7.0 vol% (for the grey-greenish fragment). Minor phases detected are oxides with variable composition, Fe-sulfide. FeNi metallic alloy, Ca-carbonate and Ba-sulphate thin veins are also found.

Geochemistry: Olivine Fa_23.7±7.9 (Fa_13.2-41.6, FeO/MnO= 85.0±8.2, n=35); low-Ca pyroxene Fs_18.7±6.2Wo_3.4±1.1 (En_68.7-85.7Fs_12.2-27.1Wo_2.1-4.3, n=4), pigeonite Fs_18.3±6.0Wo_7.3±3.9 (En_60.8-83.6Fs_10.8-24.9Wo_5.1-14.3, n=5); high-Ca pyroxene Fs_20.3±4.9Wo_28.6±12.1 (En_39.4-58.9Fs_13.9-24.7Wo_16.3-41.5, n=4); calcic plagioclase An_96.8±0.6 (An_95.1-97.9Ab_2.1-4.8Or_0.0-0.1, n=31); oxides with intermediate spinel-hercynite composition (atomic ratio Mg# = 60.3-61.3) and intermediate magnesiochromite- hercynite composition (atomic ratio Cr# = 23.4-66.3 and Fe# = 30.8-52.7), FeNi metallic is kamacite with Ni=2.0 wt% (n=1).

Classification: Lunar (troctolitic anorthosite, breccia) based on Stoeffler et al. (1980)

Specimens: Mark Lyon holds the main mass.