This is a nice big, FRESH, block of the El Hammami meteorite from Mauritania.
History (Writeup from Meteoritical Bulletin #82): In 1997 January, an unknown mass of material, possibly broken apart from a single large stone, was sold to meteorite collectors by nomads near the town of Mhamid, Morocco. The nomads claimed that this meteorite was found to the south, in Algeria (~29º50'N 5º50'W), in the direction of a fireball seen in 1995 January. In 1997 September, the same nomads shipped a fragment of a meteorite that they claimed was seen to fall on 1997 August 10 to Mr. Edwin Thompson. In 1997 November, Thompson traveled to Mauritania and collected six fresh-looking stones totaling ~200 kg (individual masses of 80, 51, 30, 26, 8, and 4 kg) at the base of the El Hammami Mountains in Mauritania (1000 km southwest of Mhamid, Morocco), probably in the place where they fell.
Classification and mineralogy of El Hammami stones (A. Rubin, UCLA): olivine, Fa18.8; pyroxene Fs16.7Wo1.4; shock stage S2; contains metal veins; petrologic type 5.