I also observed 2 types of crystals from ISO rex, but only at freezing temperatures ... that is what I called the rock chunks that form at the bottom and which are easy to decant from IPA and the very fine snow that will be too fine for decanting and requires filtering. But both only came in freezer :surprised Anyways if you only got
Mescaline Citrate / CA / Water then any crystals can only be the true
Mescaline Citrate, so hopefully it's just fine?
About Sodium Sulfate I would really say no. In general you can say it being like this:
REX vom NPS: used for Freebase-Alkaloid, Salts from Alkaloids + low-polarity organic acids (boiling Heptane even dissolves a very small amount of DMT-Benzoate) but no Alkaloids + mineral acids (*HCl, *H2SO4, ...)
REX vom Alcohols (MeOH, EtOH, IPrOH, Butanol): used for Salts from Alkaloids + organic acids, Salts from Alkaloids + mineral acids (*HCl, *H2SO4, ...) but no Freebase-Alkaloids (will not precipitate)
So you see when using a solvent which is very non polar (Toluene to Heptane) you can rex at maximum a salt which has 2 components that are organic molecules.
When using a solvent which has 1x R-OH (even lower polarity like Butanol) you can rex at maximum a salt which has 1 component that is inorganic (like anion = Cl-). But in order to dissolve and precipitate a salt which has 2 components that are inorganic (like Na+ OH-) it is still not enough. Only a few examples still dissolve in alcohols, like KOH partially.
Therefore 2Na+ SO4(2-) would probably not even dissolve in hot IPA. But in any way, a simple rule how you can start with REX if you dont know much about polarity:
Freebase = NPS like Heptane
Salt from Freebase + low-polarity acid = NPS like Toluene
Salt from Freebase + high-polarity acid = (any aliphatic) Alcohol
Citric acid is super polar, so only IPA will work, as solubility in EA (already very polar) is still pretty much 0.