Authorities say the two men burst into Omega Millennium on Nassau Street around 4:30 p.m. Saturday and threatened workers with a gun.
They tied up the employees with zip ties and a cord, grabbed the jewels and ran off.
No injuries were reported.
The first suspect is described as a black male, approximately 40 years old, standing 6-foot-2 and weighing 175 pounds. He was last seen wearing a black North Face jacket with a purple hooded sweatshirt.
The second suspect is described as a black male, approximately 40 years old, standing 6-foot-1 and weighing 200 pounds. He was last seen wearing a burgundy leather jacket with a purple hooded sweatshirt and a pair of dark sunglasses.
Anyone with information in regard to this incident is asked to call Crime Stoppers at 1-800-577-TIPS (8477).