What Am I Riddles

Question: I am duplicate of you, but only lighter. What am I?

Question: You wait for it. It cracks, stays for a moment, and then vanishes before your eyes. What is it?

Question: Upon your lonely journey I accompany you, whether you travel through endless mountains or seas of blue. Wherever you go, I keep your place. Lost you're not, when I'm embraced. What am I?

Question: Remembered are the days when I was used, bloodied and beaten... I was abused. Death surrounded me, and it mattered not, as no matter the pain I inflicted, I'd never rot. What am I?

Question: I know all, have seen all, yet I am not conscious. Looking back upon me shows mistakes and also good things. Looking in the middle of me shows opportunities to be exploited. Looking forward upon me shows the effects of decision. What am I?