Hmmm. So I was interested and was able to track down a little bit of info on the etymology and use of prefix cyan in chemistry. FYI sodium cyanoborohydride is typically a white crystal and has no relationship to the blue/purple whatsoever.
Stolen from another website:
"The immediate source of its use in science is French cyanogène, the name given to the compound radical by Gay-Lussac. He called it that because it first had been obtained by heating the dye pigment powder known as Prussian blue."
Here is the chemical formula for it,
Feᴵᴵᴵ₄[Feᴵᴵ(CN)₆]₃
Prussian blue while it does have a carbon nitrogen bond, the blue is not related to that particular bond.
"The intense blue color of Prussian blue is associated with the energy of the transfer of
electrons from Fe(II) to Fe(III). Many such
mixed-valence compounds absorb certain wavelengths of visible light resulting from
intervalence charge transfer. In this case, orange-red light around 680
nanometers in wavelength is absorbed, and the reflected light appears blue as a result."
Anyway, this is not confirmed, but I did just hear from a friend that all of this super dark purple MDMA that's going around the USA right now was supposedly smuggled into the country in wine, which I do know, has been done. I was thinking it was intentionally dyed, but I really don't know. Also from another friend, the super dark purple MDMA was lab tested and found to be only 84% MDMA HCL, so yeah, its not very pure.