Luminol is a versatile chemical that exhibits chemiluminescence, with a striking blue glow, when mixed with an appropriate oxidizing agent

Oxidizing agent

An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...

. It is a white to slightly yellow crystalline solid that is soluble in most polar organic solvents, but insoluble in water.

Luminol is used by forensic investigators to detect trace amounts of blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 left at crime scene

Crime scene

A crime scene is a location where an illegal act took place, and comprises the area from which most of the physical evidence is retrieved by trained law enforcement personnel, crime scene investigators or in rare circumstances, forensic scientists....

s as it reacts with iron found in hemoglobin.