Resin is the dried sap of fragrant trees and flowers, and is the purest form of incense. Resin is one of the ingredients in stick incense, but with resin there are no fillers or other substances: just the pure essence of the plant.
Usually, resin incense is ground to powder or broken down to be burned on incense charcoal. Resin incense can also be ground and blended with other resins.