Ice is a potent, smokable form of methamphetamine, while crack is a potent form of freebase cocaine. The substances are smoked in a similar fashion and both provide the user with an immediate, intense high and increased alertness. Unlike the 15-minute high produced from using crack, the high from smoking ice can last from 8 to 24 hours. In contrast to cocaine, which is derived from the refined leaves of the South American coca plant and then imported, ice is synthesized in a chemical laboratory. Crack is usually packaged in glass or plastic vials and sold in small quantities of 300-500 mg.
Ice is used by placing the substance in a glass pipe, heating it, and inhaling the resulting vapors.
The vapors enter the bloodstream directly through the lungs and are rapidly transported to the brain. When ice is heated, its solid crystals turn to liquid. When it cools, ice reverts to its solid state and is therefore reusable. Since ice is odorless, it can easily be used in public without being detected. In addition to its use for recreational purposes, ice is often used in the workplace to increase alertness.