Mendota is the informal name given to a strange rocky material found by a meteorite hunter near Mendota Illinois. The material is strange and appeared to be a meteorite at first. It was dense, attracted to a magnet, it set off a metal detector, and it had veins of metal inside when cut. It also has some odd angular inclusions. When freshly cut, the metal sparkles like the metal seen in meteorites, but it dulls over time as it oxidizes. In total, a couple of kilos of this material was recovered.
Samples of this material were sent to a lab for analysis. The lab confirmed the presence of nickel, but said the material is not meteoritic. So, it's not a meteorite, but nobody knows exactly what it is. Best guess is some sort of weird slag. Pieces are distributed worldwide in collections and it's a good example of a meteorwrong.
Refer to the photos. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown. It is an endcut that weighs 64 grams. Your purchase will include an ID label.