Here is some info on and the make-up of rings,
some giant rings (like the biggest around Saturn) are invisible and mostly consist of dust.
most rings are made up of dust, or dirty ice.
Saturn's rings are held in orbit through gravitational interactions with billions of other particles and Saturn its-self
here are some more relevant facts about asteroids and asteroid fields
sometimes when objects 1/50,000 the size of the asteroid impact the asteroid it can brake into a family of asteroids, or a giant ball of dust and rock
asteroids can have moons/satellites orbiting them(see 243 Ida)
asteroids can have "land"slides that can cover up craters
asteroid fields(contrary to popular belief) are not full to the brim with asteroids and a danger to traverse (but that would be no fun for a game about space travel, and fighting)