HPHT-Grown Near-Colourless Synthetic Diamond with Detectable GR1 Defect.

Prof. Kazuhiko Ito of Kyoto Gakuen University (Kameoka, Japan) and colleagues have grown large single crystals of synthetic forsterite, tephroite and other olivine compositions (Ito et al. 2003a, b). THE JOURNAL OF GEMMOLOGY, 37(5), 2021 467 GEM NOTES been subjected to post-growth high-pressure, high-temperature (HPHT) processing (Eaton-Magaña & Shigley 2016). Most HPHT-grown colourless to near-colourless synthetic diamonds are type IIa or IIa+IIb with greenish blue fluorescence, moderate to strong long-lasting phosphorescence and a cuboctahedral growth pattern. [Extracted from the article]