NWA 8417 (LL7) SOLD OUT

A 221.5g stone with partial crust was purchased out of Morocco in April of 2014. Initially thought to be a diogenite, the stone was sent to Dr. Anthony Irving who surprisingly determined the stone to be a very fresh LL7 (metachondrite). While hard to capture on camera, it is FILLED with green orthopyroxene giving the slices an all around green color. To me… the matrix of this stone is Katol on steroids!!! While there is some staining on most slices, each features tons of these green inclusions. It is by far the greenest chondrite I have ever seen! Slices were prepared both by myself and Montana Meteorite Laboratory. Each will come with a labeled meteorite box.

Writeup as follows:
Physical characteristics: Single stone (221.5 g) partly coated by brownish-black fusion crust. The interior is pale green with sparse black grains and visible specks of metal plus brown stained areas.

Petrography: (A. Irving and S. Kuehner, UWS) Very fresh, metal-poor specimen with a complex texture. Large (up to 5 mm across) oikocrysts of orthopyroxene enclose numerous small chadacrysts of olivine, but there also are regions of about equal size composed mostly of olivine and orthopyroxene exhibiting triple grain junctions. Chondrules are absent. Olivine and orthopyroxene of all textural types are highly equilibrated. Accessory minerals are clinopyroxene, Ti-free chromite, sodic plagioclase, K-feldspar, albite, stained kamacite (<1 vol.%), troilite and taenite. Geochemistry: Olivine (Fa26.5-26.6; FeO/MnO = 54-63), orthopyroxene (Fs21.6-21.7Wo2.8-3.2; FeO/MnO = 31-32), clinopyroxene (Fs10.5-10.7Wo40.4-39.6). Oxygen isotopes (K. Ziegler, UNM): acid-washed subsamples analyzed by laser fluorination gave the following results, respectively: δ17O 3.789, 3.862, 3.729; δ18O 4.937, 5.020, 4.890; Δ17O 1.182, 1.211, 1.147 (all per mil). Classification: Ordinary chondrite (LL7). The very low metal content, the large size of the oikocrysts (presumably representing former chondrules), and the FeO/MnO ratios in olivine are features consistent with LL parentage (prior to thermal metamorphism). Oxygen isotope compositions plot within the overlapping fields for LL and L chondrites, and the olivine and pyroxene compositions fall within the gaps between the accepted ranges for L and LL chondrites, but if all the characteristics are considered together then this specimen is best classified as an LL7 chondrite.

Showing all 14 results