This meteorite is a half-stone. These are some of the most unusually shaped meteorites. They come in wildly twisted, beautiful knucklebone shaped masses.
Many pieces have holes due to eroding away of the large Troilite nodules that they contain.
They are a type of iron meteorite called an anomalous iron, with a meduim to coarse crystalline makeup. Mundrabillas were discovered with their rusty oxide surfaces by a prospector who found the fall on the limestone plateaus of the Nullarbor plain in 1911.