Hashish consists of the THC-rich resinous material of the cannabis plant, which is collected, dried, and then compressed into a variety of forms, such as balls, cakes, or cookie-like sheets. Pieces are then broken off, placed in pipes, and smoked. The Middle East, North Africa, Pakistan, and Afghanistan are the main sources of hashish. The THC content of hashish that reached the United States, where demand is limited, averaged about 5 percent in the 1990s.
Source: DEA - Hashish has an average of 2 to 8 percent THC and can contain as much as 20 percent THC.