Actually the routes to LSD are well characterized, and while there may or may not be other methods that are not available in the literature it is doubtful this is the case, and word of mouth is not the primary means of transmitting the information regarding the synthesis. Even a cursory search on the Internet will yield the most common routes, and the chemical abstracts and other literature contain a few more. So it's hardly 'forbidden information', it's actually a pretty well-explored realm of synthetic chemistry precisely because it is illegal so there have been many novel syntheses that have been developed to skirt precursor bans and the like.
I don't think that anyone has established that sub-active doses of certain chemicals can color the experience. If you've got a source for that idea that I don't know about I would happily change my views on the subject but the musings of random Bluelighters or off the cuff comments made to the media by imprisoned synthesists don't really cut it. And furthermore it actually is relevant whether or not whatever impurities are active at <1mg, because even if it were proven true that sub-active doses could color the experience it would matter what the active dose actually is, because that would determine what fraction of a dose could be present, which would then affect the plausibility of the sub-active dose as colorant argument. Meaning that if sub-active doses are shown to be able to color the experience, they're likely to do so at perhaps 50% of the active dose, but not 10%.
Well, the difference between purportedly pure clear crystals and impure, not-clear colored crystal is not crystal polymorphism, it's just purity. Crystalline polymorphism is like getting acid that's 90% pure that is needle-like crystals, and another batch that's also 90% pure but has hexagonal crystals. These are just made up examples, as I don't know what the various polymorphs of acid really are.
There's also the issue of potentially having hydrated polymorphs that would have a different shape and composition and texture, but the shape of the crystal or the level of hydration if present doesn't have anything to do with how pure it is. Crystals are by definition made out of only one chemical, because that is how they form on the molecular level: Brownian motion leads individual molecules of the chemical to bang into eachother. At some point two of them will fuse together, and more and more molecules will then attach themselves in a regular, repeating geometric pattern to that initial crystal seed. The specifics of what that geometric pattern is and how the molecules are oriented relative to one another within the crystal structure determines what the overall shape and physical characteristics of the crystal will be, and these various forms, differentiated based on the nature of the pattern and intermolecular orientation, are what polymorphs are.
Since only molecules of the same chemical can attach themselves to the growing crystal while properly fitting into the pattern, other molecules will not have the right shape and won't fit, so the crystal will be nearly pure. I say nearly because occasionally the crystal will grow in such a fashion as to surround a molecule of a different chemical within a single molecule sized void in the pattern. These inclusions are flaws in the crystal. The slower the crystal grows, the less likely it is to accidentally envelop other molecules of different chemicals, and this the purity of that crystal will be greater.
Hydrated polymorphs are crystals where there are individual molecules of water that are included in the repeating geometrical pattern. Necessarily, the pattern will be altered in order to accommodate the steric bulk of the water molecules, resulting in a different overall shape for the crystal and a different set of physical properties. Typically the more water is included the softer and easier to melt the crystal will be. If there's one water molecule per molecule of whatever the crystal is otherwise made of, that is a monohydrate. And the more water molecules per molecule of the other constituent, the greater the numerical prefix before the word hydrate, the easier it is to melt, and so on.
---
As for why a batch would come out looking like black sludge, I would put my money on impure precursors. You're supposed to purify your precursors before use if they, for example, come from a plant. Otherwise you'll have a whole mess of other compounds that are going to be acted upon by the other reagents in the synthesis. Some of the impurities won't react and will come through unchanged, some will be chemically altered, some may fuse with eachother, some may impede the progress of the synthesis of the intended product, and so on. So we purify our plant-derived or otherwise impure precursors.
The thing is that when you recrystallization or otherwise purify the precursor, inevitably you lose some of the desired, intended precursor. So if you're a greedy, money hungry bastard who doesn't give a shit about the quality of their product, they purify the precursors less, if at all, so that the end product will weigh more. But naturally that increased weight will be mostly made up of impurities that went through the synth with the intended product. Some of the increased weight will be the form of the intended product, because the synthesist didn't lose as much of the intended precursor due to purification so there's more starting material to work with, but it comes at the expense of also including a bunch of nasty junk crap in the final product.
If a given contaminant in the precursor does indeed become chemically altered by the other reagents, then potentially you'll end up with even some of the intended product remaining unreacted because the other crap used up some fraction of the molar weight of that reactant. Yeah, you could just use a large excess of that reagent (one of the two reacting compounds will always be the limiting reagent, and the other will be added in excess, since adding precisely the same molar amount of each is not likely or even practical to attempt), but the reagents or this kind of thing expensive and hard to get, so you don't want to waste them. Furthermore, it is also the case that some reactions require certain ratios of the various reagents, and not only will using to little of one of those reagents fuck up stuff (like LAH, in certain reactions, and now no more will be said), using too much can also throw off the reaction as well.
Redox reactions are the prime example, you can totally over-reduce your whatever into totally useless inactive garbage, etc. case in point: my first synth ever, methcathinone, the first time it went perfectly, which I'm proud of to this day (for getting it right my first time ever!), but the second time I did something or other in the math wrong and ended up oxidizing the shit out of the precursor that shall not be named with the reagent that shall not be named, and ended up with a dish full of disaster.
Aaaaand then the third time... I got busted by my mom halfway through! I was like 15 I think, using reagents and glassware stolen and smuggled home in my backpack from the high school chemistry lab (they need found out but this is an awful idea nonetheless, in case anybody reads that and decides to be clever), she was so pissed off, it is emphatically not fun at all to have your parents catch your methlab red-handed. But my point is that redox reactions are sensitive to improper amounts of the redox-img reagent *in either direction, excess or shortage*. And having crap in your shit that is unpredictably using up a reagent – or not, you'd have no way to know ahead of time – is thus an obviously awful idea even if you're not pulling a redox, and just one of the many reasons that people who don't purify their precursors should they be less than reagent-grade should have no business making acid – or any drug for that matter – in the first place.
Sure you could then purify the end product, as you should be doing anyway, and you'll lose mass there too, both of the intended product and any impurities, but this is the old ounce of prevention pound of cure deal. It's always best to purify BEFORE reacting, because you just plain don't want a bunch of random shit messing with the synth.
Fascinating, I missed that about the doubled dose! No wonder it was not the same, we don't even have to invoke differences in how your body or mind were feeling etc etc at all, the reasoning is right there for all to see!
