Pu-Erh Tea
Formed from compressed green or black tea, Pu-erh is an ancient type of tea known for its earthy flavor and medicinal value. It is slow-aged over many years to bring out a very refined flavor profile. Pu-erh tea is the only form of tea that increases in both flavor and value with age with some Pu-erh tea cakes going for over $2000 at auction.
Read about pu-erh tea on wikipedia >>