ecstasydata.org is the site where you can match the design/name of your pill with the same type of pills that have been tested.
by the way, i've tried purple apples before (doublestacks), and they're very good. it feltt like nothing but mdma =D

also: once you know the taste of pure x (it helps if you chew up your pills once in a while to familiarize yourself with the VERY pungeont taste), you don't forget. it has a very displeasing, bitter, distinct taste that is unique to mdma. if you have a pill and it doesn't taste like the chemically unique flavor of x, it's not pure. you can almost always tell.