Police were called to Tindalls Diamond Jewelry at 1003 Washinton Boulevard just before 6:00 p.m.
Officials say two men and two women entered the store, separated and used a diversion to distract store employees.
One of the suspects grabbed an unspecified amount of loose diamonds before the group fled the store and sped off in a black Audi Sedan with Pennsylvania tags.
No one was hurt in during the heist.
Anyone with information is asked to contact police.