Diamond mining and diamond synthesis: Which is more efficient?

Vladislav Zhdanov - Professor at the National Research University Higher School of Economics and former Vice President of ALROSA (2015-2018). He is a physicist by profession. Vladislav Zhdanov was educated at the Ural Federal University (General...

21 november 2022

The success of TAGS over the past 5 years has encouraged many large tender houses to establish regular and sizeable tender operations in Dubai

Mike Aggett is an experienced Private Consultant with a demonstrated history of working in the mining and metals industry. Skilled in Luxury Goods, Business Planning, Sales, Gemology, and Jewelry, Mike is a professional who graduated from Dover College...

14 november 2022

It all starts with stones - it is they that give impetus, determine the image and embodiment

Maxim Selikhov is the founder of the SelikhoV Diamonds brand launched in 2006, and the company manufactures unique handmade jewellery with rare high-quality gemstones. He is also known as a collector of unique and large-size jewellery stones who considers...

07 november 2022

‘Our technologies – CVD machines and growing technology – are game changers’, asserts Arnaud Flambeau, Executive Chairman, 2DOT4 Diamonds LLC

Arnaud Flambeau is the Executive Chairman of ‘2DOT4 Diamonds LLC’, Dubai, a fully integrated lab-grown diamonds company. The Company provides rough 'as grown' diamonds, in-house polished IGI certified loose polished diamonds and high-quality...

31 october 2022

Stargems brings the DaVinci system to Botswana

Stargems, which was founded by Shailesh Javeri in 1981, has diversified into manufacturing, wholesaling, retailing and tendering or auctioning of diamonds and diamond jewellery.
It is also one of the leading players in the manufacturing, wholesaling...

24 october 2022

GSI discovers inconsistent lattice defects in CVD growth process

29 september 2022
Recently a CVD lab-grown diamond weighing 1.547ct., emerald cut, VS1 clarity and H colour was submitted to the Gemological Science International (GSI) Mumbai Lab for Post Growth Treatment Identification, which revealed interesting results says GSI.
The absorption spectra in the mid-infrared region showed typical absorption features of type IIa, as seen in CVD lab-grown diamonds. No additional absorption features were observed. Photoluminescence spectroscopy with 532 nm excitation showed peaks at 737, 637 and 575 nm. The 737 nm and766 nm emission systems are associated with silicon-vacancy centres, including moderately strong NV emission lines at 575 and 637 nm.
Raman microscope with 532 nm spectrometers showed extremely strong NV emission lines at 575 and 637 nm, the absence of 596/597 nm doublet indicates post-growth treatment.
DiamondView revealed a strong greenish-yellow fluorescence when observed length-wise, and interestingly, on a rotation of 180 degrees, strong orange fluorescence was observed. 
Due to prolonged observation in DiamondView, when the DiamondView was turned off, an intense red phosphorescence for a few milliseconds (10-15 milliseconds) was observed which quickly changed to yellow. 

Image credit: GSI

Such observations have not been reported earlier in CVD diamonds. This intense red phosphorescence was observed only after prolonged exposure to DiamondView.
The possible reason for different fluorescence colours, in different directions and phosphorescence, is assumed could be due to inconsistent lattice defects during the CVD growth process.

Aruna Gaitonde, Editor in Chief of the Asian Bureau, Rough&Polished