It's a fire? No, it's a stone What is it?

I can be a children's toy or an instrument in the professional league, Either way, both can cause auditory fatigue.

I am a tiny slice, so thin and slight, a narrow shard that catches light. Not whole, not much, just barely there, a little piece of something rare.

I am a word made up of two words, yet they are unrelated to my meaning A world where you have freedom to explore and interact I am a game with no defined goal, and the decision is yours to decide

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?