Northern Virginia Criminal Justice Academy (NVCJA) Practice Exam

What color does marijuana typically turn during a field test?

1. Green

2. Purple

3. Red

4. Blue

The correct answer is: Purple

During a field test for marijuana, the substance is commonly expected to show a color change that can be indicative of its presence. The purple color change is associated with certain chemical reagents used in field tests, specifically when testing for cannabinoids. The use of specific reagents that interact with compounds found in marijuana can produce a purple hue, suggesting a positive identification of THC or other cannabinoids. This is a scientific reaction based on the chemical properties of the substances being tested, which is understood by law enforcement personnel and forensic experts in the field. In contrast, while the other colors (green, red, and blue) may be associated with other substances or effects, they do not represent the common positive indication for marijuana in field testing scenarios. Therefore, purple is the color that generally signifies the presence of marijuana during a field test.