From Soshitsu Sen's Chado: The Japanese Way of Tea (1979):
The charcoal is arranged in a set pattern in the container. The long, white sticks are charcoal made from azalea branches and painted with gesso. The black charcoal is made from any of a variety of woods (20).
The artisan who crafts the scoops will usually give a specific poetic name to each, such as "Outgoing Boat," "Incoming Boat," "Spring Wind," "Firefly," "Demon's Arm," and so on (26).