The extracted oil from cannabis. There are many different forms such as BHO, wax, shatter, etc. It tends to have a much more concentrated level of THC than marijuana flower. To produce the hash oil a solvent must be used. There are many different types of solvents that can be used to produce hash oil. The solvent used will determine what form of hash oil will be created. The process goes something like this: the flower is ground then flushed with the solvent followed by heat or cold and pressurization to release the oil. the consistencies range from slick oil to gummy toothpaste to hard & brittle to a powdery substance.