What is the physical appearance of heroine?

The physical appearance of heroin can vary depending on its form and method of production, but it is commonly identified as a black-brown tarry goo, particularly when referring to "black tar heroin." This type of heroin is sticky, resembling a thick paste or goo, which is a result of the processing method used for purification. Black tar heroin is often the least processed form, containing a higher quantity of impurities, which contribute to its dark color and gooey texture.

Other forms of heroin might appear as a white or off-white powder, but in the context of this question, the distinctive appearance of black tar heroin makes it a notable identifier. It is crucial to recognize these characteristics, as it aids law enforcement professionals in identifying and responding to heroin-related incidents effectively. The other answers do not accurately reflect heroin's most commonly encountered physical state in illicit use.