Methamphetamine — its slang terms include ‘crystal,’ ‘crank,’ ‘glass,’ ‘ice,’ ‘speed’ and ‘Tina’ — is a powerful, addictive synthetic stimulant that causes the brain to release a surge of dopamine, creating a high that lasts from six to 24 hours.
Like cocaine, meth comes in two forms: powder or rock. The powder form is usually white, odorless and bitter-tasting and can be snorted, smoked, eaten, dissolved in a drink and ingested, or heated and injected. The purer form of the drug, called “crystal,” “glass” and “ice,” appears as clear, chunky crystals that are usually smoked or injected. Meth can also come in small, colored tablets, but they are less common. http://www.pbs.org/wgbh/pages/frontline/meth/faqs/