One major unfortunate downside of dealing with street ecstasy is that there is no way to tell the quality or the substances contained by color, shape, imprint/stamp, etc. There are simply too many types and a lot of copycats. Many times the only difference between adulterated garbage and the real deal comes down to one small detail. This is a problem with copycats. Everything will be the same except perhaps that the imprint might be facing the opposite direction. There is no way to know the chemical makeup of an "ecstasy" pill without putting it through chromatography/spectrometry. Most of us, not having access the necessary machines or the know to use them, must either resort to sending a pill to a testing facility and paying for the process (such as with EcstasyData.org), or using a reagent testing kit to get a general idea of the classes of substances contained. Even the reagent tests cannot tell you exact substances or quantities/ratios, but at least can give you a better idea of what you're dealing with, by turning different colors, which indicate the presence of certain classes of psychoactives.My advice, if you regularly encounter different types of E, would be to get a reagent test. This will at least let you know if a pill is adulterated, and with what type of substance.Be safe