In Japanese, ”chashaku” translates to “tea scoop”. The chashaku was originally a Chinese innovation. They were originally intended as a standard, general dispensing spoon. Early chashakus were made of metal and ivory, or some combination of the two. When the spoon design was introduced to Japan in the Muromachi period (circa the 14th and 15th century), it was utilized specifically as a tea powder spoon. However, the ivory ones were too delicate and the metal spoons were too wide.
Since then, chashakus were developed from other woods. But most standard chashakus are made of bamboo. Design-wise, they are made of one narrow piece carved from bamboo.