It's pretty damn hard to tell without gauging based on how it makes you feel (even then it's not so reliable, as I'm sure you know). How long your product stays clear/white, and how little residue is left when the puddle's all gone is a decent indicator -- but it's possible the stuff was as pure as snow and not actually cut, just had something left over from the cook is all. So it's not always a good indicator.Needle-like patterns when it recrystallizes are from one cut or another, or so I've gotten the impression. Little pinwheels or spiderwebs seem to be associated with purer stuff -- some of the best I've seen recrystallized into almost nothing more than a trail of pinwheels laid right next to eachother. I've also seen at least one person say they think this is misinformation and that the pattern is a result of the amount & duration of heat, and nothing more. I don't see how that can be when the patterns I see from one sack are generally the same, but switching to another product (a moment later I mean) produces a different pattern. Unless I subconsciously heat different bags differently or something...Supposedly you can get a good idea by examining the shards -- apparently a lot of cuts produce slightly different formations, but I've never been able to tell, honestly. Things like a raised ridge on a shard are supposed to indicate a sizable cut or something, but again, I've never really been able to see much of a pattern in the shards themselves. It does seem reasonable though.The more bitter it tastes, the purer it likely is. That's a pretty reliable one, but I can never seem to decide if one batch is more bitter than the last one I had -- I can just never remember the exact taste to judge by.You can be more accurate about it and do something like take 50mg, crush it to a powder, do an acetone wash and then once it's dry as a bone weigh the result. Allow for a small amount of loss because of stray H2O in the acetone, and the rest of the weight that vanished was pure cut. Note that what you're left with isn't necessarily pure meth, though, either. You can be sure what you took out was cut though (plus that small amount of meth loss).Part of my problem, personally, is that sometimes the same exact sack will feel differently for me at different times or on different days. I rather doubt the purity varies based on the phase of the moon, though, so taking into account that a given day's physiology has a lot to do with how good meth seems to be, it's really difficult to isolate specific traits that indicate purity, ya know.I've read MSM causes a cloudy layer to build up on whatever the smoke touches, but... that kind of seems to happen at least a little with all meth I've bothered paying attention to. Can't comment on it, myself.There's also something or other about dropping a shard in bleach and seeing if it fizzes or some such thing... I never really felt like dropping my meth into bleach or just didn't have any around, so I've never tried that one. Anyway, that's about all I can think of. Corrections and contrary opinions are welcome, as always.