Armageddon Riders

Rare artifacts are similar to how pick ups looks. But they look slightly different. They are star shaped, looking similar to a starfish and are purple. There are 25 to be collected and once collecting everyone of them the trophy will pop. Here is a picture of what they look like:

I have also included a video for the location of all 25 rare artifacts. Which my youtube pal, FrankNStein has kindly let me use.