The cannabis plant is covered in resinous glands called trichomes, which contain THC, CBD, terpenes, and other compounds. When these trichomes dry and break off of the plant, they become kief.
Kief is usually darker than trichomes, ranging from gold to brown. It’s a powdery substance that is somewhat sticky, though less so than trichomes on a bud.
The powder is commonly collected in grinders, which are used to break down cannabis into small, even pieces for rolling or to pack bowls. Grinders usually have a separate chamber at the bottom called a kief catcher for this purpose.
Kief can be added to bowls or joints for an added kick. It can also be pressed into hash.