Green/Pink was the original 7.62NATO Dim Tracer tip color code, later it became Green/White. Green/white was the original tip color code for frangible, but they haven't made that version of frangible in decades, so I guess they felt they could get away with reusing the tip color. When the XM276 dim tracer was standardized about Desert Storm, they decided all the dim tracer series would be violet. There's a 5.56 version, a .50 BMG version, etc.
Besides Green/Pink, Green/White, and, now Violet, there were other tip color codes used, White/Pink comes to mind as well.