GLS Gales Gemological Research Association  is a private independent gemological research laboratory, specializing in the determination of origin and authenticity reports for ruby, moissanite, sapphire and emerald plus other important coloured gems .

GLS is to protect all buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality. An GLS certificate clearly discloses the details of gemstones , providing confidence for both buyer and seller.The GLS report is based on a precious stone analysis , which is designed to identify the species and variety of gemstone. The GLS report clearly states whether the gemstone is natural or synthetic, provides other data describing its shape , cut , weight , measurements , color , transparency and major optical characteristics, and also includes a detailed photograph of the gemstone.