The hollow rock that is called a meteorite. Is actually a geode. Geodes start life as an air bubble in lava, or as an abandoned animal burrow, or space created by long rotted away root. However, the space is created. Sometimes these spaces have a flow of ground water passing through them. And in a lot of cases that ground water is carrying elements and crystals suspended in the water. Over tens of thousands, even hundreds of thousands of years. The crystals and or elements build up and the end result is a geode. Most a very beautiful. But they are not meteorites.