The robbery occurred as the casino celebrated its 10th anniversary with a concert featuring The Roots, Jill Scott and comic Aziz Ansari, The (Atlantic City) Press reported.
Police said three men broke into the jewelry store just before 9 p.m., quickly grabbed merchandise and fled in a car, WPVI-TV in Philadelphia reported. Investigators said surveillance cameras captured footage of the robbers, but little information was available on their vehicle.
The thieves were not believed to be armed.
The Borgata Hotel and Casino opened July 2, 2003.