The First Type: This type is very little and does not lead the (envier) to harm (others)-either by way of (hatred in) his heart, (speech of the) tongue or (deeds of the) hand; rather the person has some envy in his heart but he only deals with his Muslim brother through what Allaah loves.
The Second Type: The envier desires that the blessing (bestowed on the one he envies) should cease. He hates that Allaah should give blessings to His slaves; rather he (desires) that the envied person should remain in that state (of deprivation)…
The Third Type is Al-Ghibtahl: It is when a person wishes to be like another person without desiring that the blessing possessed by that person should cease. The person who has this type of envy is not blamed; rather this is very similar to praiseworthy competition to excel another in good deeds.
[Source: Badaa’i al-Fawaa-id’ 2/237’ by Imaam Ibnul Qayyim (rahimahullaah); slightly paraphrased and abridged]