^ But you won't know what you're actually getting, and you'll have to rely on your dealer to give you accurate dosing information, you won't be able to google it on your own or ask here, because we're not going to have any more idea as to the identity of your substance than you do. If they tell you that it's "super-potent mescaline" and you only need 20mgs (or even worse, "one line" or "one bump"), then it's definitely not mescaline, whose doses are much higher starting at about 200-300mg. If you twist your dealer's arm they might be able to be more specific about what they're selling and will tell you that they just call it mescaline to make it easier to sell to newbies to psychedelics, but in this case how much can you trust that they're giving you accurate information now when you just caught them bullshitting you? If they're a really low-level dealer, they might not even know what it is they're selling and that it can't possibly be real mescaline, they're just passing on the info they got from their source and didn't bother to question it or do research themselves.
There are much better vendors who state the exact chemical names of their products and aren't afraid that their customers are going to be scared off by their weird alphabet-soup names. Some customers would be, but if they're too impatient to do a google search on an unfamiliar term to find out what it is then maybe they're not mature enough to use psychedelics responsibly, and would be more likely to have a bad trip and probably not be a good repeat customer to have to deal with. Conversely, if a vendor is willing to lie to reach the largest customer base possible, and thus are probably getting a lot of one-off customers they'll never see again, then they're unlikely to conscientious about other details, such as making sure they send you the right product and not get it mixed up with something else, or not mixing up the dosing information for their different types of "mescaline" (this could be harmful or even deadly if they tell you to take a 2C-C-sized dose for what's really DOC or 25C-NBOMe, for example). So if you really want 2C-B, DOx, or another cool phenethylamine you read about in PiHKAL, then go to a vendor who sells it as such and doesn't try to pass off all phens as "mescaline", just to make it easier on themselves.
If it's on a blotter or powder if you're very lucky it will be DOM - DOM is great, could even be the equal of mescaline. More likely just be some shit research chemical.
If it's on blotter then it can't possibly be mescaline, it's gotta be some mystery substance that is active under 5mg or so because any more than that wouldn't fit on the tabs.
I know in some areas and at some times the only way to get 2C-B or DOM from a dealer was to ask for "mescaline" or "synthetic mescaline", but we should really discourage using the name of one chemical as the slang term for a completely different chemical as much as possible, or casually referring to an entire class of chemicals by its most well-known member, there is already enough ignorance and confusion in the psychedelic user community as it is.