Crystalline methamphetamine

Ice, also called shabu, crystal, or crystal meth, is a very pure, smokeable form of methamphetamine that is more addictive than other forms of the substance. Ice, which is primarily manufactured in Asia, can be described as large translucent to white crystals, or crystallized coarse powder. In a method of smoking sometimes referred to as 'chasing the dragon,' a term commonly associated with smoking opium or heroin, users heat ice on a piece of aluminum foil and inhale the released vapors -- usually through a straw or similar device. It can also be administered via snorting, swallowing, or injection. The snorting of ice is associated with nasal damage due to its crystalline form.
According to the Dangerous Drugs Board (DDB) of the Philippines, shabu has consistently ranked first among the most abused drugs in the Philippines since it gained popularity in 1994. Crystal is also the predominant form of methamphetamine in Japan, Brunei, Singapore, and Malaysia. Injection is the predominant route of administration only in Japan, although corresponding levels of HIV have not been seen there.

For more information, please see
http://www.unodc.org/drugs/en/get-the-facts/methamphetamine.html