Mesosiderites

The mesosiderites are named for the Greek words mesos for "middle" or "half", and sideros for "iron", meaning "half iron". In fact, they are typical stony-iron meteorites, consisting of approximately equal portions of nickel-iron metal and silicates. Excluding all probable pairings, the mesosiderite group comprises about 50 distinct members, while seven members represent witnessed falls.
Texturally, mesosiderites are a complex mixture of a nickel-iron metal portion and a heavily brecciated silicate portion, consisting of mostly pyroxene and plagioclase. Strangely, the silicates are obviously evolved igneous rocks, representing the crust of an achondritic parent body. They are quite similar to eucrites, diogenites, and other members of the HED group, even plotting on the same oxygen isotope fractionation line. However, the metal in mesosiderites is similar to group IIIAB irons, obviously representing the core of a distinct, differentiated asteroid, genetically unrelated to the precursor of the eucritic and diogenitic portion. This suggests a complex formation history for the mesosiderites and their parent body.

Estherville Location:Emmet County, Iowa, USA, 43°25'N 94°50'W Fell:1879, May 10 17:00 hrs. Type: Mesosiderite-A3/4 Description: Several large masses, of weight of over 700 lb. (317.5kg), the two largest weighing about 437 lb. (198.1kg) and 151 lb. (68.5 kg) respectively, and hundreds of small fragments of nickel iron, fell, after detonations and the appearance of a brilliant fireball. . . . analysis of metal, 9.0% Ni, 9.0 ppm Ga, 52.3 ppm Ge, 2.7 ppm Ir. (From Catalogue of Meteorites (2000)).
				Estherville Huge large specimen showing many vacuoles and large orthopyroxene crystals. A Must !! 1755 gr SOLD
Close Up of the 1755 gr specimen