What The Hell Is This White Shit I Been Getting

i been getting this white "dope" up here that def. does not feel the same as some nice dark brown shit, it keeps me fron getting sicks and kinda speeds me out dosent slow me down.... smells kinda like dope, the vinegar acetyl anhy. smell but anyone could add that. I really think its fentanyl cut heavily into whatever this white shit is.... when I marquis test it, it goes purple, but marquis isint for testing dope..... at least it can identify it as an opiate though..... my dude suppsedly got the shit from detroit I saw a huge chunk of it like 4 inches by 4 inches straight white....... is there ANY real white dope coming from anywhere? I think the mexican realize that they can produce fentanyl cheaper from precursors rather than have to grow out poppies and do all that processing to make it into real dope they are just synthing fentanyl and rockin it up, could even be deso :/ is there a test kit that will differentiate between different types of opiates eg fentanyl, deso, dia, etc???? is there a lab where I can send this shit??? i really wanna know wtf it is....it does not make me itchy like my nose like real dope i dunno thanks