(IDEX Online) - GIA has highlighted another fraudulent attempt to pass off an "impostor" lab-grown diamond as a higher-value natural stone.The lab has already reported a number of gems being submitted for grading with fraudulent inscriptions.In the latest incident a 3.075-carat lab-grown was submitted for update in Antwerp, bearing the girdle girdle inscription of a 3.078-carat natural stone.The accompanying report was for a 9.33mm - 9.38mm x 5.74 mm, Internally Flawless, G, natural diamond with triple excellent make.The "impostor" stone, described by GIA as near-identical at first glance, measured 9.39mm - 9.41mm x 5.76 mm, VVS2, H, with a triple excellent make.GIA says that as a matter of course it overwrites the counterfeit inscription with the words "Laboratory-Grown"."This unfortunate situation demonstrates why it is important, especially in any transaction where the buyer does not have a trusted relationship with the seller, to have the diamond grading report updated before completing a purchase," said Tom Moses, GIA executive vice president and chief laboratory and research officer. In January, GIA's Johannesburg lab identified three cases of synthetic moissanite being passed off as diamonds, all bearing fake inscriptions.Pic shows a diamond newly inscribed as "Laboratory-Grown" by GIA