Envy vs Jealousy

From Andrew - obviously both are deplorable:

"What I find most annoying is...envy.
Have you ever spent an evening with the envious type? This is the guy or (or woman) who will bend your ear for hours speculating at great length about what a co-worker or neighbor is earning---usually with an undertone of resentment. Generally, the envious mind tends to focus on the material possessions of other people --- the exact amount of Pete's bonus, what Randy paid for his house, the cost of Gretchen's new phone, how Ron was able to afford his vacation to Italy etc. To these people there's no such thing as ability or hard work --- other people simply "gamed the system" or "figured out a wrinkle" that allowed them to get ahead. The envious man is the type that will literally froth at the mouth at the sight of a guy with an attractive woman. He'll get visibly angry and repeatedly point out that "he doesn't deserve her." In some instances, It will make him so upset, if he's had a few, he may even invent a fancied grievance and try and start a fight with a complete stranger.

As a society we've been led to believe that jealousy and envy are interchangeable. They're not. Jealousy actually serves an important social purpose. It typically involves an individual, a cherished relationship, and a fear that the relationship may be in danger. While there is certainly a small minority of "jealous types" who take this emotion to violent extremes and do great harm, by and large, some sociologists believe a certain amount of low-intensity jealousy is good for society as it helps maintain social stability.
Envy, on the other hand, is the irrational resentment of another because he or she possesses something you don't have and it can create all sorts of ugliness."