Une remarquable tourmaline elbaïte non cuprifère

Franck Notari (1) (2), Féodor Blumentritt (2), Yolchanok Srinaka (1), Natthawut Saenkuntha (1) Abstract The popularity of Paraíba-type tourmalines is mainly due to their remarkable colour, often described as « neon » blue. Many tourmalines with this colour are traded under the label Paraíba, but sometimes mistakenly. Today, gemmological laboratories devote particular attention to the detection of […]

Un exceptionnel zircon photochrome de 9,89 carats

Féodor Blumentritt(1) & Franck Notari(1) ABSTRACT We were fortunate to observe and analyze a remarkable 9.89 ct zircon showing a strong color change from vivid orange to dark brown after longwave ultraviolet illumination (excited state). Its color comes back to vivid orange after being kept in the dark at room temperature for several months, or […]