Description
On offer: a 2.776g part slice.
Dimensions: ~36 x 25 mm
What you get: this 2.776g part slice, a plastic box with label at the back, a signed Certificate of Authenticity.
Type: Acapulcoite
Country: Western Sahara
Date of find: 2022
Total mass: 550 g
Northwest Africa 16397 (NWA 16397)
(Northwest Africa)
Purchased: 2022 Oct
Classification: Primitive achondrite (Acapulcoite)
History: Reportedly this stone was found in Western Sahara
Petrography: (K. Metzler, IfP) Recrystallized rock with abundant 120° triple junctions, consisting of olivine, low-Ca pyroxene, Ca-rich pyroxene, plagioclase, and Fe-Ni metal. Accessory phases are troilite, Cr-spinel and merrillite. Silicate grain sizes are mostly between 100 and 200 µm.
Geochemistry: Mineral compositions and geochemistry: Mean olivine composition: Fa8.3±0.2 (Fa7.9-8.5); Fe/Mn (at.): 15.5; n=10. Mean low-Ca pyroxene composition: Fs8.4±0.2 Wo1.8±0.6 (Fs8.0-8.8 Wo0.8-2.6); Fe/Mn (at.): 10.7; n=11. Mean composition of Ca-rich pyroxene: Fs3.5±0.3 Wo44.0±0.7 (Fs3.1-4.3 Wo42.0-44.6); Fe/Mn (at.): 11.2; n=11. Mean feldspar composition: An14.2±1.2 Or2.4±0.4 (An12.4-15.8 Or1.7-3.0); n=11.
Classification: Acapulcoite, based on mineralogy, mineral chemistry and mean grain size of silicates.
