Pure black olives from a tree!
The item id for Olives 0 in unturned is 6000. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Useable: Consumeable
Size_X: 1
Size_Y: 1
Size_Z: 0.25
Food: 5
Asset_Bundle_Version: 2