Could easily have fent. If it's fake...which it is....it is moreikely to have something nasty.
Test with a fent strip or if you're gonna smoke it anyways...since it's crack (I've smoked plastic knowing it was fake just hoping one hit would be real).
.You're best off remaking cocaine then crack or crushing and homogenizng the best you can to avoid dying from fent hotspots.
If you remake regular coke then rock again and it doesn't work....youndont have cocaine
Also take very small hits (not exactly crack behavior I know)