Which characteristic describes heroin?

Heroin is an opioid that can have various forms and characteristics, making it important to understand its common attributes. Pure heroin is indeed rarely sold on the street; street heroin usually contains a mixture of other substances in order to dilute it for distribution and to increase profits. This dilution can affect its potency and purity, leading to inconsistent effects for users.

Additionally, heroin is typically found as a white powder, although it can also appear in other forms such as a sticky tar substance. The presence of white powder is often associated with higher purity but is not exclusively representative of all heroin on the street.

Given this context, the correct answer encompasses both notable characteristics: that pure heroin is rarely sold in its pure form on the street and that it is often associated with a white powder appearance. Therefore, the most comprehensive choice, which reflects these characteristics accurately, is that both statements are true.