Chergach, Whole Crusted Impact Melt Breccia Meteorite, 8.7g

Chergach is a witnessed fall from Mali in 2007. Many stones from this shower struck a village, causing panic and a sensation across the countryside as black stones rained from the sky following a series of detonations. Analysis revealed the meteorite to be a shocked H5 chondrite.

The specimen being offered here is a whole, uncut stone. It is an IMB type (impact melt breccia) which one of the two known lithologies for this meteorite. It has fresh black crust over most of the surface with a few patches of grey matrix showing through breaks in the crust. It weighs 8.7 grams

Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown. Your purchase will include an ID label and padded storage box.

From the Meteoritical Bulletin Entry on Chergach -

Chergach 23° 4147’’N, 5° 0053W

SW El Mokhtar, Erg Chech, Timbuktu district, Mali

Fall: 2 or 3 July 2007, daytime

Ordinary chondrite (H5)

History: In fall and winter, 2007 ~100 kg of meteorites were collected in the Erg Chech, north of Taoudenni. Nomads reported the stones fell after a smoke cloud was seen and several detonations were heard over a wide area during daytime in July 2007. The finder of the first meteorites was Mr Ouled Bleila, who died in a car accident on his way back from the trip to the Chergach strewn field in October 2007. According to the Tuareg people from Algeria who visited the fall site in September 2007, the elliptical strewn field stretches for more than 20 km in a northeasterly direction. No fireball was reported.

Physical characteristics: A large number of fusion-crusted stones have been recovered, the largest ones are 17.8 and 13.9 kg, the smallest ones about 1.5 g. Total known weight ~100 kg.

Petrography: (E. Gnos, MHNGE; B. Hofmann, NMBE, M. Eggimann, UBE/NMBE) Mean chondrule size is 0.38 mm (n = 61). Mean size of plagioclase grains is ~20 μm. Troilite is polycrystalline, rich in silicate inclusions, and shows diffuse boundaries to metal. Some metal is rich in silicate- and troilite inclusions. No Cu metal observed. Shock stage is S3, some shock veins are visible, no weathering (W0). In addition to this dominant lithology, a significant number of stones consist of chondritic clasts (H5 S3-4 W0, identical to the homogeneous lithology) set in a fine-grained, black, silicate impact melt matrix with abundant droplets of metal and metal-troilite. Shock stage of small clasts is up to S4.

Classification: Ordinary chondrite (H5), some stones suggest an H impact melt breccia. S3, W0.

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