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 […]
Emmanuel Fritsch1, Nicolas Hébert2, Feodor Blumentritt1,3, Cassandre Moinard1 ABSTRACT A parcel of 13 kg of hackmanite from the Mogok area, Myanmar triggered some surprising observations that contribute to the knowledge of hackmanite, the photochromic variety of sodalite. Firstly, we point out that nearly 350 samples reach exactly the same color saturation under UV-rich natural sunlight […]
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 […]
