Oolongs

Oolong teas are named for the original teas made in the style, called Wū Lóng (乌龙, lit. "Dark Dragon") for the loose leaves that were long, curly, and almost black in color. 

Oolong teas are teas which range in oxidation between 20% and 80% generally. They can be found in bright emerald greens like those popular in Anxi and Taiwan; they can also be quite dark and mineral, like those made in the Wu Yi mountains. All in all, they offer a complex and delicious flavor.