I'm not sure where you're from but the street level cocaine in the US is on average only about 10-20% pure... or even LESS.
It's mostly non-cocaine that you're ingesting. Pure cocaine on a street level is essentially a myth. Most street cocaine is maybe 10-15% cocaine has amphetamines and other crap added.
I can't really tell you what is in that cocaine or why it tastes weird, only that if your cocaine tastes weird it's because some low/mid level dealer doesn't know how to cut their drugs properly. If it tastes weird I would avoid it.
The fact that cocaine is "rocked up" or hard/chunky ultimately has ZERO impact on how pure it is. Anybody can rock up some cocaine by mixing it with liquid/X/and heating it....
Just because your dealer has "rocked" cocaine means SHIT when it comes to how pure it is. If it tastes weird - avoid it.
There is a similar fallacy among meth users, that large clear crystals = good meth - they couldn't be further from the truth.