October 2024 was marked by a new record: New Diamond Technology, together with NPK Almaz, have created the world's largest nitrogen-free single crystal diamond (colorless, type IIa) weighing 70.72 carats. This was achieved thanks to new efficient technological solutions for the growth of large-sized electronic-quality single crystal diamonds.
Dimensions of the crystal: 20.29 x 21.33 x 15.59 mm. Growing time: 20 days.
The analysis of geometric and morphological parameters of the crystal shows the possibility of manufacturing several 3/4 inch matrix plates for subsequent iterative growth of structurally perfect substrates of electronic quality crystals up to 2 inches in size by the CVD method (according to the Large Area Device-Quality Diamond Substrates (LADDIS) program), as well as matrix replication of 3/4 inch electronic quality plates using the CVD method. In addition, there is a possibility of manufacturing a unique colorless nitrogen-free fancy-cut diamond (cushion or radiant) of large sizes (over 25 carats). The 70.72-carat diamond is the largest colorless single-crystal HPHT diamond grown to date. It is known that there are CVD diamonds of larger sizes, but they are not single-crystal and are made by successive growth of several layers of the crystal, which can be easily detected by fluorescence methods.
Currently, the market for laboratory-grown single crystal diamonds (both HPHT and CVD) and diamonds made from them (LGD) faces a supply glut. The rapid growth of their production volumes (by 7-10 percent annually) led to a decrease in the cost of these diamonds to record lows. According to Rapaport data, they sell at 99% discount compared to similar natural diamonds.
As a result, a number of the largest factories stopped growing jewelry-grade rough diamonds, and turned to traditional products such as diamond powders, polycrystals and other goods for instrumental purposes.
However, a sharp increase in the volume of grown raw materials and a decrease in their cost also has a positive side. The main purpose of these diamonds is to use their unique electrophysical, thermal, optical and mechanical properties in the production of new-generation equipment in the electronic and optical industries, medicine, space, nuclear energy and other high-tech areas, with previously unattainable functionality. Record technical characteristics of diamond-based devices are available when growing crystals of electronic quality as opposed to jewelry quality. These crystals have a whole range of strict parameters imposed on diamond substrates or optical elements for high tech industry.
Galina Semyonova, Editor in Chief of the Russian Bureau, Rough&Polished
