Proving pink diamonds are from Argyle: What is a Delta Certificate?

Proving pink diamonds are from Argyle: What is a Delta Certificate?
A Delta Diamond Laboratory certificate is proof that a diamond has undergone scientific examination to verify it has the colour and characteristics identical to those from the Argyle deposit.

Historically Argyle only certified pink and blue diamonds of specific sizes. For example, in the 1980s and 90s certification was only given to stones of 0.20 carats and larger. 

The organisation’s processes changed over time and, in 2021, pink diamonds over 0.08 carat are automatically certified. Unfortunately this evolution has resulted in there being many Argyle pink and blue diamonds on the market today without these certificates. Had they travelled through the current processes they would, of course, automatically qualify for an Argyle certificate.

Having had a close relationship with the mine since its opening, we have diamonds purchased from Argyle in our vault that were unearthed in the years before the official “Argyle Certificate” even existed!

In a world first, Nina’s are thrilled to now offer these stones with their own “Certificate of Diamond Origin”. 

Introducing: The Certificate of Diamond Origin from DELTA Diamond Laboratory

As they did in Argyle’s own laboratory for 30 years, those at the Delta Diamond Lab continue to perform scientific analysis of diamonds. Stones certified by them are verified to have colour and characteristics identical to those that are unique to, or consistent with diamonds from the Argyle deposit. 


Proving a diamond's origin


What makes an Argyle pink diamond? 

Argyle pink and blue diamonds exhibit a range of characteristics that need to be considered when verifying their origin. In many instances no single characteristic, such as fluorescence, is sufficient for verification so multiple tests are conducted on each stone. 

The Delta certification process considers all of these factors, testing for: Fluorescence, Infra-red Absorption, Visible absorption, Visible microscopic features and Photochromism 

Certificate of Diamond Origin | Delta Diamond Laboratories

Where a diamond is not found to have characteristics consistent with the Argyle deposit, then no origin certificate will be issued. 

Further details and explanations of data are available on the Delta website.

Fact-checked by: Laura Brown

Related products