Firms with the Accredited Gem Lab (AGL) designation prove to their customers and clients that they are vested in thoroughly inspecting gemstones and jewelry. More importantly, each Accredited Gem Lab must have an AGS titleholder on staff, with a minimum of a Certified Gemologist (CG) or Certified Gemologist Appraiser (CGA) title to oversee its use. This ensures that a fully-credentialed gemologist with the proper knowledge handles gemological testing and appraising.