LOOSE-CHAMELEON-DIAMOND. Description: 1 oval; faceted diamond 1.26 ct.; fancy light brownish greenish yellow/VS1; chamaleon diamond. Finish: very good; symmetry: very good. Laser-gravure GIA 5211076378.Chamaleon diamonds are by far the most rare variation of the already rare fancy colour diamonds. In contrast to the other diamonds these diamonds can change colour temporarily if they are exposed to high temperatures or a change in light. According to history; this changing colour effect was documented in 1943 for the first time when a customer made a complaint about the diamond which she bought from Peter Kaplan. She bought the diamond in a light green but noticed that it turned dark green if it laid in her jewellery casket for a longer period of time. She returned the jewel without knowing that she possessed an absolute rarity which was worth multiple times of the original price.Although this colour changing effect is now known for some time; it remains a mystery why some diamonds do this. Scientists were able to find several theories since 1943 but none of these could prove the cause sufficiently. The largest found chamaleon diamond so far weighs 31.31 carats and was bought by Chopard 2017.Enclosed GIA certificate from 05/2020.Art trade; Van Ham.