Resins are aromatic saps from trees and bushes which we burn on incense charcoal disks for their pleasant fragrance. Powders are simply powdered resins and herbs blended together for burning on charcoal disks. Resins and powders will not burn without the charcoal. They need a special burner to contain the intense heat of the charcoal disk: one made of stone or metal.
So many great memories!
I was cleaning out my storage shed a few summers back and found glass bottles filled with incense I must have bought back around 1998.
They both still burned clean and smelled great-- and it wasn't exactly climate controlled in that puppy! I still use the bottles with refills.