Visual observation on the part of scientific investigators is the first step in the analysis of drugs. Visual analysis of drugs includes observed color, crystal structure and all supporting evidence which links drugs to the scene of a crime. Accurate visual evidence can eliminate the possibility of certain drugs (and the associated cost to labs). If a green substance thought to be drugs is brought into the lab, there would be little point in investigating for cocaine or heroin in the initial test.
Table INSERT - Identification of drugs based on visual observation.
Visual observation of drugs can also be supplemented by manuals such as the PDR and the Drug Enforcement Agency’s (DEA) guide to logo identification. LSD, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA, ecstacy) are often marketed emblazoned with logos or cartoons. By comparing images and logos of recently obtained unknowns with an index of seized drugs (such as the one found at http://www.ecstasydata.org/) a presumptive judgement can be made as to where the type of pill came from, the active ingredients and what adulterants are likely to be found in the pill.