Alright, seeing as how no one has had a chance yet to do this, looks like the duty has fallen upon me to familiarize you with the normal bluelight mescaline line...heres the scoop, in brief.
Mescaline is the single most commmonly faked drug out there. Simply put, mesc ain't sold on the street, period. I doesn't matter if its your longtime hookup whose been getting you bomb shit for 10 years, or the sketchpad junkie you just met in some dark ally, whoever they are, they absolutely, positively DO NOT have mescaline. Why you ask? Pure economics. There is no inncentive to make the shit b/c its basically requires the same amount of time/effort/resources as producing mdma (another phenylethamine sp?). Average dose required for mdma is about 100 mg (thats even a bit high). Average mesc dose is about 400 to 450 mg. Thus, it makes much much more sense to produce mdma or one of a number of other drugs. Chemists just ain't going to all the trouble and risk of making these highly illicit substances for shits and giggles, its a cash game.
Sorry to break it to you, but unless you have a hookup with a chemist that truly works for the love of psychadelics...or if you are paying like $150 for a gram, you are getting ripped off. To repeat, its not impossible that you can find mescaline, just as its not impossible you will pay $20 for a cap of mdma filled with 500 mg of pure mollie, but its just not likely AT ALL.