If you are jealous, you feel unhappy because someone has something that you want and cannot have or you feel angry and bitter because you think that someone is trying to take a lover or friend, or a possession away from you. Jealousy always involves a general feeling of resentment towards a perceived rival. The emotion is truly negative.
My girlfriend gets very jealous if I even look at another girl.
ENVIOUS:
If you are envious of someone, you wish that you had something nice or special that someone else has. You may not feel angry and bitter. For example, you are envious of your colleague. She has just got a promotion ~ better salary and more responsibility. You won't blame your colleague. You are only angry at yourself for not having a better education or necessary skills.
Judy knew she was beautiful and enjoyed the envious looks of other women.
I’m envious of your new coat ~ it’s lovely.
參考: Longman Dictionary and Oxford English Dictionary