^^^No you won't see the fentanyl, and you definitely won't see some of the more potent analogs.
The purest heroin I used to get back when I used in mid 00's, was an off white/beige that almost at times looked like swirls of the two colors. It's not the color though but the shape and texture of the rock (if it's powder it's already garbage) that shows good heroin. It should have somewhat jagged edges and when you crush it down it'll break into pieces that are jagged. (Hard to describe...) Also when you finally break it down to a powder it has this lightweight yet dense feel to it. And it should have zero vinegar smell, if any the tiniest bit when you crack a rock open.
I'll say one thing too, erowid is rarely right about their dosages usually aiming on the low side.. They are dead on for their pure heroin dosages though. Even at my worst I was probably only using 150-200mg a day and that had me nodded out almost non-stop. Shit like that can be dangerous though, even after being cut all to hell I watched a dude almost overdose. Sorry reading these threads gets the memory flowing, been almost 10yrs and I'd be lying if I said I still didn't think about it once in awhile.
I'm thankful back then fentanyl wasn't as common but I do remember one time getting a rock that looked grey and felt like fentanyl. I used to smoke fentanyl a lot when I was a kid so I know the feeling (I had 100ug patches, 100mg morphine sulfate, and 160mg oxy's laying around growing up, I still thank god I didn't REALLY like opiates til the end of high school or I'd be dead right now), tiring and relaxing but not that gorgeous euphoria that keeps you coming back.
With fentanyl laced dope, even the current test kits aren't reliable.. Your best bet is to start low and reallly evaluate the effects to see, there's a clear difference in my opinion between the two.
-GC