Phencyclidine (PCP)
Also known as "angel dust" and is a hallucinogen. It is difficult to estimate the current use of phencyclidine in the United States because many individuals do not recognize that they have taken it. PCP is frequently laced with other illicit substances (such as marijuana) and the buyer not made aware of its presence. PCP use in the U.S. dates back to 1967 when it was sold as the "Peace Pill" in the Haight-Ashbury district of San Francisco. Its use never became very popular because it had a reputation for causing "bad trips." PCP use grew during the mid-1970s primarily because of different packaging (sprinkling on leaves that are smoked) and marketing strategies. During the 1980s it was established as the most commonly used hallucinogen, with the majority of users 15 to 25 years old. Although phencyclidine was initially developed by a pharmaceutical company searching for a new anesthetic, it was not suitable for human use because of its psychotropic side effects. PCP is no longer manufactured for legitimate, legal purposes. Unfortunately it can be made rather easily and without great expense by anyone with a basic knowledge of organic chemistry, making it a prime drug for the illicit drug industry. It is available illegally as a white, crystalline powder that can be dissolved in either alcohol or water.

*source www.Wikipedia.org and http://workplace.samhsa.gov/Glossary/glossary.aspx