Ritalin isnt an amphetamine.
Dexies are = dextroamphetamine.
The reason the poster above said speed=meth=methamphetamine is because almost all "speed" made and sold in australia is probably methylamphetamine (whether it should be called that or not).
The simple reason...the pseudoephedrine route. It is very easy with the right ingredients.
Its true that the same methods can turn PPA into amphetamine, but as amphetamine is less desired than meth and PPA is harder to get than pseudoephedrine, this is almost never done.
Synthesising amphetamine from the other routes is a lot harder (the same would go for meth), and backyard chemists would not be doing it.
People on BL who have bought the E supreme have semi confirmed this. Every bit of "speed" someone has tested so far that i am aware of, has reacted postively to meth.
Now i am not saying there isnt ordinary amphetamine out there; i mean its out there in the form of dexies isnt it.
Personally i doubt dl-amphetamine is greatly more stimulating than just dextro. Maybe it is. But it pales in comparison to meth.
I think the waxy, yellowy looking rock is probably some rather inexperienced cooks meth effort, and "crystal meth" is the same stuff, just in the hands of something who has had the skill and patience to make it well and then purify it even better.
All meth can be smoked i think; meth's crack equivalent is called "snot". A horrible sticky mess, and not really desired.
Ice is another thing which for me still remains a mystery. Very pure crystal meth or 4-methylaminorex; its likely thats it both but should only be the latter.
I'd be curious to know whats coming out of SE Asia in enormous quantities and called ice. Its very well made, unlike backyard jobs, but its true identity at this stage is not definitely known.