Cocoa Beans

Cocoa Beans (also known as the Brown Dye) are a material used for making Cookies and brown wool.

History
Cocoa Beans were initially introduced in the Beta 1.2 update, but were not able to be obtained without an inventory editor.

In Beta 1.4, Cocoa Beans were formally brought into the game as a reward found in dungeon chests (53% chance). Also as of Beta 1.4, brown sheep naturally spawn which made obtaining brown wool easier. Since snapshot 12w16a, cocoa beans are obtainable in bonus chests, and since 12w18a, cocoa beans have a small chance (0.5%) of dropping from destroyed jungle tree leaves in a similar fashion to apples, making cocoa beans a renewable resource for the first time.

Jeb said during his Dreamhack presentation that cocoa trees are pending. In snapshot 12w03a Cocoa Bean Pods can be seen on jungle leaves; Jeb stated he might be adding them as a drop from leaves much like Apples if he couldn't find a way for players to farm them, and in the 12w18a snapshot, Cocoa Beans now drop from jungle trees.

Cocoa Beans are among the rarest obtainable items on old maps (after cookies) as they can only be found in dungeons generated after the Beta 1.4 update. The use of cookies as a 'trophy item' gives cocoa considerable value on unmodified servers, even more so than diamonds. With cocoa beans becoming obtainable from jungle trees since snapshot 12w18a, they are no longer as rare to obtain as before.

On May 8th, 2012, Jeb confirmed on twitter that Cocoa Beans would get their own plant. They appear to be farmable off of the sides of Jungle Trees, and have roughly 2 to 5 stages of growth. http://i.imgur.com/d1yU3.png