253 Mathilde
253 Mathilde is very dark. The asteroid has a number of very big craters, with the individual craters being named for coal fields and basins around the world. The two biggest craters, Ishikari (29.3 km) and Karoo (33.4 km), are as wide as the asteroid's average radius. The impacts appear to have blown big volumes off the asteroid, as suggested by the angular edges of the craters.