loader image
Connect with us

DiamondBuzz

GIA Studies Unusual ‘Mottled’ Pink Diamond Formed Through Multiple Treatments

Analysis reveals how HPHT, irradiation and heat transformed a brown diamond into a fancy pink stone with a rare visual pattern

Published

on

132 views

The Gemological Institute of America (GIA) has examined a rare pink diamond displaying an unusual mottled appearance, shedding light on how a combination of advanced treatments can influence both colour and visual texture.

The 1.10-carat round diamond, submitted to GIA’s New York laboratory, was graded as fancy deep brownish orangey pink. According to findings published in the fall issue of GIA’s Gems & Gemology journal, the stone stood out due to its patchy, mottled look—an uncommon feature in treated pink diamonds.

GIA’s analysis revealed that the diamond had undergone multiple enhancement processes, including High Pressure-High Temperature (HPHT) annealing, laboratory irradiation, and subsequent moderate heating. These treatments worked together to create nitrogen-vacancy (NV) centres within the stone, which are responsible for producing the pink colour. Prior to treatment, the diamond was originally brown.

Microscopic examination showed that the mottled pattern extended from shallow depths all the way to the polished surface. Further testing using visible and near-infrared (Vis-NIR) spectroscopy identified features consistent with irradiation and heat treatment.

GIA noted that the distinctive mottled appearance likely resulted from an uneven distribution of NV centres, influenced by the diamond’s nitrogen aggregates. While detailed mapping was not conducted to confirm this theory, the findings provide valuable insight into how complex treatment pathways can create unexpected visual effects in coloured diamonds.

Continue Reading
Advertisement JewelBuzz Banner
Click to comment
Subscribe
Notify of
guest
0 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments

DiamondBuzz

NDC Welcomes Angola’s ENDIAMA and SODIAM as New Members

Angola’s ENDIAMA and SODIAM Join Natural Diamond Council to Drive Global Industry Growth and Sustainable Development

Published

on

898 views

The Board of Natural Diamond Council (NDC) is delighted to announce that Angola’s ENDIAMA E.P. and SODIAM E.P. have formally joined the organization as members, following the completion of all legal and regulatory requirements for accession.

ENDIAMA E.P. – Empresa Nacional de Diamantes de Angola (National Diamond Company of Angola) is Angola’s state-owned diamond mining company, responsible for managing the country’s diamond resources and ensuring their sustainable development for the benefit of the Angolan people. SODIAM E.P. – Empresa Nacional de Comercialização de Diamantes de Angola (National Diamond Marketing Company of Angola) is the state-owned diamond trading company and unique channel for Angolan diamond export, overseeing the marketing and commercialization of Angola’s natural diamond production on the global stage.

This milestone follows the principles outlined in the Luanda Accord co-signed in June 2025 by representatives of diamond producing countries and industry stakeholders, including Angola, Botswana, De Beers and midstream representatives, signaling a shared commitment to support the natural diamond industry and the communities whose lives and livelihoods depend on it.  The Accord reflects a shared vision to take decisive action, backed by sufficient resources, for the long-term health and integrity of the natural diamond industry through the NDC’s marketing and education work to inspire consumer desire for natural diamonds. The recent receipt of Angola’s financial contribution stands as a tangible testament to the proactive commitment set in motion by the Luanda Accord.

“The future success of the industry will be defined by our ability to work together to communicate the true story of natural diamonds – both their desirability and their ability to drive development.  I am therefore delighted to welcome ENDIAMA E.P. and SODIAM E.P. as NDC members,” states Sandrine Conseiller, CEO of De Beers Brands and NDC Chair.

“Through growing the organization’s representation across the natural diamond value chain, the NDC will be better positioned to amplify the collective voice of the industry, strengthen consumer education, and reinforce trust in natural diamonds as rare, precious creations of nature with profound social and economic impact.”

“Natural diamonds are not only the world’s most precious and timeless stone- but they are also the bedrock of Angola’s prosperity providing stability and livelihood for millions of our people,” says Dr. José Manuel Augusto Ganga Júnior, ENDIAMA E.P.’s Chairman. “By joining the NDC we are signaling our commitment to ensuring a bright future for the natural diamond industry – and Angola’s position in it- through revitalized and sustained investment in global generic marketing executed by NDC.”

“We are delighted to join the Natural Diamond Council, strengthening Angola’s voice in the global diamond community and fostering collaboration that promotes responsible growth, transparency, and shared prosperity across an industry which plays a vital role in shaping the future of diamond-producing nations, driving sustainable economic development, and ensuring that the benefits of this natural resource contribute meaningfully to national progress and wellbeing of our communities,”states Dr. Eugénio Pereira Bravo da Rosa, Chairman of SODIAM E.P..

At the same time, the NDC Board of Directors is actively reviewing its governance documents to enable broader participation from across the natural diamond value chain. These updates are intended to support greater inclusivity, transparency, and engagement, ensuring the organization continues to evolve in step with the industry it represents.

Together, these developments mark a positive and forward-looking chapter for the Natural Diamond Council as it advances its mission to protect and promote the integrity, desirability, and enduring value of natural diamonds worldwide.

Continue Reading

Trending

JewelBuzz is Asia’s First Digital Jewellery Media & India’s No.1 B2B Jewellery Magazine, published by AM Media House. Since 2016, we’ve been the trusted source for jewellery news, market trends, trade insights, exhibitions, podcasts, and brand stories, connecting jewellers, retailers, and industry professionals worldwide.

We would like to hear from you...

GET WHATSAPP NEWS ALERTS

0
Would love your thoughts, please comment.x
()
x