Large Colorless HPHT-Grown Synthetic Gem Diamonds from New Diamond Technology, Russia

Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study

“…High-pressure reactor chamber design and control of diamond growth parameters have advanced considerably in recent years. The consistent production of larger as well as colorless HPHT synthetics is now possible, and several HPHT synthetic crystals can be grown simultaneously within the press (D'Haenens-Johansson et al, 2015). In general, HPHT growth proceeds at temperatures and pressures designed to approximate the conditions of natural diamond growth.…”

Coessential-connection by microwave plasma chemical vapor deposition: a common process towards wafer scale single crystal diamond

“…It has been reported that the largest HPHT Diamond belongs to Russia's New Diamond Technology company [17]. Its largest Diamond rough has even reached 40-60 carats, as shown in Figure 3, and it is expected to break through 100 carats in following years.…”

Raman Spectroscopy of Ancient Beads from Devín Castle near Bratislava and of Four Intaglios from other Archaeological Finds in Slovakia

“…The orange/pink/purple luminescence of the sample clearly originates from the NV 0 centre with its zero-phonon line at 575.1 nm, while a green component observed under 405 nm laser excitation originates from the 467.7 nm centre (Figures 3 and 4). Besides the Si centre-which also can be detected in some HPHT-grown synthetic diamonds (D'Haenens-Johansson et al, 2015) and very rarely in natural type IIa stones (Breeding and Wang, 2008)-the 467.7 nm centre is a characteristic defect in untreated CVD synthetic diamond (Martineau et al, 2004). In addition to the NV-centre emissions, a large number of very sharp and typically rather weak peaks are evident in the PL spectra, all of which appear to be characteristic of CVD synthetic diamond, and which are-in the experience of the authors-unknown in natural diamond.…”