(IDEX Online) - De Beers today said it will no longer sell lab grown engagement rings, after a three-month trial reinforced its belief that they are "unsustainable" as a commercial proposition."Retailers already need to double the number of LGD carats sold every two years just to maintain a flat absolute gross profit," the company said.Lightbox, the De Beers lab grown division, dipped its toe into the bridal market in June, with its first ever lab grown engagement rings, carrying the tag line "Because great chemistry deserves great chemistry". Most were priced around the $2,500 mark, from a 0.3-ct tw three-stone ring priced at $500 to a $5,000 two-carat round brilliant solitaire engagement ring with a stone graded as colorless/VVS+.Lightbox CEO Antoine Borde said at the time that the company was running a small in-market test of consumer preferences in the lab grown diamond engagement ring segment.He said: "We are undertaking the test now to better understand more about consumer interest in lab-grown diamond engagement rings, and to better understand how Lightbox's offering of clear information and accessible prices resonates in this segment."In a statement De Beers today said the trial was now over, and it would no longer be selling lab grown engagement rings."Through the test the company deepened its understanding of LGDs and evaluated the changing landscape and consumer perceptions associated with them," it said."Lightbox will continue to focus on where it sees the most promising future opportunities in the sector - in fashion jewellery and in loose stones at accessible price points - and will not sell LGD engagement rings."The company added that specific details of the test results were commercially sensitive, but the sales were in line with their expectations.De Beers launched Lightbox in May 2018, saying it would supply "high-quality, fashion jewelry" for "less serious occasions".Pic courtesy Lightbox