Narcotics Division detectives were watching a group loitering at an open-air drug market at Governor and Carroll streets -- an area known for frequent violence -- when they spotted the silver handgun in the boy's waistband, Public Safety Director Jerry Speziale said.
The teen began to tip away as investigators approached him, but he didn't get far, Speziale said.
They found him carrying the heroin, crack and 9mm SCCY handgun reported stolen out of Virginia, the director said.
Delinquency complaints were signed against the boy charging him with drug and weapons possession, as well as receiving stolen property and possession of a large-capacity ammunition magazine.
He was sent to the Essex County Juvenile Detention Center in Newark to await a closed-door hearing in the Family Part of Superior Court in Paterson.
Click here to follow Daily Voice Jersey City and receive free news updates.