Stony-iron meteorites form in places where metal and silicate are mixed. Pallasites probably form when the olivine-rich mantle of an asteroid mixes with the metallic core. Mesosiderites are mixtures of iron-nickel metal and basalt and probably formed by the collision of two asteroids. Iron Meteorites Iron meteorites are really composed of iron and nickel and are extremely dense. They are pieces of the cores of asteroids.
Iron meteorites are the samples of the cores of ancient worlds.
One of the most distinguishing features of meteorites is the presence of the Widmanstatten pattern - the distinctive series of bands in geometric patterns. The presence of nickel is a universal feature of iron meteorites. If you think you have a meteorite, the following simple tests will tell if your sample is a candidate for further examination. It is important that you compare the outer surface and interior and this may require removing a small piece of the rock by breaking or sawing with a diamond-impregnated saw blade. These simple tests can be helpful in determining if a rock might be a meteorite.