Envy: you have something I want
Jealousy: I have something and I’m afraid someone might take it.
I envy my neighbor. His wife is beautiful.
I am jealous of my beautiful wife, I don’t like how she smiles at my neighbor.
Most native speakers don’t know the difference and use these interchangeably.
I am envious of your students, they have such a good teacher, or,
I envy your students, ...