how you differentiate envy and jealousy? firstly I've heard envy is good but recently i got to know its also not good... -want your clarification?!
if you are envying and thinking why he/she got that, is jealousy.. be thankful to Allah for what you got, may be someone wants what you don't think valuable... well its nature, knowing that both of them is not good but still we do it.. :p