There are major 3 types of meteors. 1) Rocky meteor 2) Metallic meteor 3) a combination of both 1 and 3.
As the name suggests - asteroids.
Pieces of rocks made of minerals similar to those that are formed the rocky planets and moons.
The asterod belt is made up of rocks and gases.
It is believed that the asteroid belt is a region where there would have been a planet, but the planet either failed to coalesce, or was destroyed by some very high energy collision.