Yes, gold has been found in New Jersey—but only in trace amounts, never commercially viable.
Small deposits near Franklin and Hamburg in Sussex County (northwestern NJ). Associated with zinc-iron mining districts (Franklin-Sterling Hill). Gold occurs in glacial deposits and quartz veins.
Recreational panning yields occasional flakes. No historical gold rush, no commercial mines. NJ's mineral fame is zinc, iron, fluorescents (Franklin minerals)—not gold.
Significant Eastern US gold: Carolina Slate Belt (NC, SC, GA, VA), Georgia Gold Belt, Alabama Gold Camp. NJ is peripheral to these provinces.