A Melee-sized Colourless HPHT Synthetic Diamond with Dislocation-like Blue Fluorescence.

The article focuses on the identification and characterization of a unique melee-sized (1 mm diameter) colorless high-pressure, high-temperature (HPHT) synthetic diamond exhibiting an unusual dislocation-like blue fluorescence network under deep-UV excitation. Despite resembling natural type IIb diamonds in fluorescence behavior and containing boron impurities, detailed microscopy and photoluminescence (PL) spectroscopy at 77 K confirmed it as an atypical HPHT synthetic diamond with Ni-related defects not previously observed in such stones. The fluorescence pattern’s origin remains unexplained, distinguishing it from known natural and chemical vapor deposition (CVD) synthetic diamonds. Additionally, the article briefly discusses advancements in Chinese freshwater bead-cultured pearls, highlighting a recently examined purplish pink pearl with a polystyrene bead nucleus identified via X-ray microradiography.