Hashish, or hash, is a drug made from the resin of the cannabis plant. It is consumed by inhaling from a small piece, typically in a pipe, bong, vaporizer or joint, or via oral ingestion (after decarboxylation). As pure hashish will not burn if rolled alone in a joint, it is typically mixed with herbal cannabis, tobacco or another type of herb for this method of consumption. Depending on region or country, multiple synonyms and alternative names exist.
Hash is a cannabis concentrate product composed of compressed or purified preparations of stalked resin glands, called trichomes, from the plant. It is defined by the 1961 UN Single Convention on Narcotic Drugs (Schedule I and IV) as “the separated resin, whether crude or purified, obtained from the cannabis plant”. The resin contains ingredients such as tetrahydrocannabinol (THC) and other cannabinoids—but often in higher concentrations than the unsifted or unprocessed cannabis flower. Purities of confiscated hashish in Europe (2011) range between 4% and 15%. Between 2000 and 2005 the percentage of hashish in cannabis end product seizures was at 18%.
Hashish may be solid or resinous depending on both preparation and room temperature; pressed hashish is usually solid, whereas water-purified hashish—often called “bubble melt hash”, or simply “bubble hash”—is often a paste-like substance with varying hardness and pliability; its color, most commonly light to dark brown, can vary from transparent to yellow, tan, black, or red. This all depends on the process and amount of leftover plant material (e.g. chlorophyll).
Hashish was the primary form of cannabis used in Europe in 2008. Herbal cannabis is more widely used in Northern America.