Since the 1940s, when the Gemological Institute of America (G.I.A.) introduced the 4C’s (color, clarity, cut and carat) as ...

Jean-Noel Soni, who specializes in colored stones, said he tries to give each one a shape that “maintains the crystal’s integrity.” ...

You may submit the polished diamond for the Diamond Origin Service, which must be accompanied by the GIA rough report number, at any GIA laboratory location around the world. Retailers have access to ...