Amphetamine vs Methamphetamine (ice)

Came accross this article about the rise of methamphetamine (ice) compared to the more traditional amphetamine .. http://www.smh.com.au/news/0012/02/review/review4.html
Not being much of a speed user I am not really sure of the difference, how would you tell the two apart in appearance and effect?

from what i know,and i might be wrong,but ICE is amphetamine thats had something added to it(forgot what the additive is)that makes it smokeable,and more pottent.
anybody feel free to correct me!
it looks like white-ish/see through sharp rocks!
havnt had it my self.Not into speedy type subs!
im shore someone will give you a more indepth answer to ya questions!
do a search!

OK
4-methylaminorex or 'ICE' (Erowid link http://www.erowid.org/chemicals/4_methylaminorex/4_methylaminorex.shtml ) is different to (meth)amphetamines (Erowid link http://www.erowid.org/chemicals/meth/meth.shtml )
Crystal Meth (the smokable form of methamphetamine, its what crack is to cocaine) is sometimes confusingly called 'Ice'.
Hope this helps.