The suspects entered the store about 9:30 a.m. near Newport Boulevard and 16th Street saying they wanted to get a ring cleaned.
The armed men then assaulted the store's owner, kicking him in the face. Police say the robbers then tied up the owner and his son and fled the scene with an undisclosed amount of jewelry and cash.
The suspects were seen driving away in a red Jeep Liberty. No suspect descriptions were immediately available.