This on-grown diamonds was color graded as Fancy Deep blue. This is a very attractive color with no other color component, a prized rarity among natural type IIb diamonds (the Blue Moon, for instance, was graded as Fancy Vivid blue). When viewed under a microscope, possible to observe the absence of color zoning, which indicates the absence of impurities of man made diamonds HPHT. No strain was observed under crossed polarizers, indicating a very low dislocation density, which is also characteristic of HPHT-grown diamonds.
Absorption spectroscopy for the mid-infrared region confirmed the sample was type IIb, with strong boron-related features at 1290, 2458, and 2800 cm–1. The average bulk boron concentration was 0.82 to 1.12 ppm, calculated according to the equation NA-ND = (1.00 ± 0.15) × H1290 ppm cm–3 , where NA is acceptor concentration, ND is donor concentration, and H1290 is peak height at 1290 cm–1. Otherwise, this large lab grown diamonds exhibited an extremely low concentration of optical defects. Photoluminescence spectroscopy was conducted at liquid nitrogen temperatures using a range of laser excitations covering the UV-visible-IR range. The PL spectra only revealed emission from a single defect species, a Ni-related emission multiplet with peaks at 483.6/483.8/484.1/484.4 nm (484 nm center) detected using 324.8 nm laser excitation. As with previous type IIb lab-grown diamonds, its visible-NIR spectrum showed a transmission window in the blue region and an absorption in the red, caused by the presence of boron, resulting in the observed blue bodycolor.

The total weight of the obtained diamonds in the amount of 18 carats, on of the the largest HPHT-grown blue synthetic diamonds. Examination of this large IIb lab-grown diamonds, combined with those previously obtained diamonds from Syntechno, illustrates the rapid progress in HPHT growth technologies.