Jewellery Technology & Machinery - JTM
The Natural Color Diamond Association forms
International Coalition of Ambassadors

The Natural Color Diamond Association is expanding its presence and influence on the international market.

Most organizations like ours are searching for ways to move forward after the impact of the world economies shutting down due to the pandemic. Like other leading groups we must re-envision our roles and our necessity viz-a-viz the needs of consumers and our industry members as we position ourselves in the new world order.

Our philosophy, transparency, education and collaborations with our sister trade groups, labs, and the media gives us the ability and strength to provide the service and the right knowledge and information about natural color diamonds.

In our effort to show a vision of leadership for the future of the most extraordinary natural gemstones, the Natural Color Diamond Association is proud to announce that we are building a United Nations of ambassadors in strategic locations around the world to promote the desire, the beauty and passion that natural color diamonds create.

Alan Bronstein
President, The Natural Color Diamond Association


Ephraim Zion is one of the original pioneers in natural color diamonds. Beginning as a diamond cutter in Israel at 14 years old, he moved to New York for bigger challenges and opportunities. The turning point in his career was the move to Hong Kong in 1971, which was already the center for jewelry gemstone trading in Asia. Ephraim's passion was inherited by his two sons who are now an integral part of the growth and innovation of the company. Today, the Dehres brand holds a most prestigious role as one of the foremost high-end jewelry manufacturers in the world. Dehres has been a leader in trading natural color diamonds for the last 50 years.

Ephraim has also held the prestigious position as a governor at the GIA from 2008 -2017. This role is only offered to the industry leaders with the highest integrity and trade accomplishments.

The Natural Color Diamond Association is proud to have Ephraim Zion as our Ambassador representing us in Hong Kong and Asia. He is a valuable asset to our goal of promoting the allure of our magical gemstones.


John Glajz began working as a managing director for fine jeweler Mondial Jewelers of Singapore at the early age of 25. John expanded his operations to create innovative concepts for the trade in Singapore and SouthEast Asia. In the 1990's John became more involved with the emerging market of natural color diamonds. While mentors cultivated his curiosity, the Argyle Pink Diamonds became the focus of his designs and projects. In 2004 John launched his Glajz brand to design unique jewelry and use exotic gemstones. John has been an Argyle partner and together have participated in one of a kind projects.

The Natural Color Diamond Association is proud to have John Glajz as our Ambassador and advocate based in Singapore. His experience and passion will help to spread our message.


The Natural Color Diamond Association is pleased to announce that our member, Matthew Aldridge will be our Ambassador based in Geneva, Switzerland.

Mathew is a second-generation connoisseur who was mentored and taught by his father. The company was started by his father Patrick, 55 years ago. Matthew, like many second-generation traders, saw the untapped potential through his passion and intuition of the evolving gem trade. Gemcut began as traders of colored stones and extraordinary secondhand jewels. It evolved into trading natural color diamonds and eventually hit its stride in the early 1990's, when Mathew was captivated by the extraordinary richness of the Argyle Pink diamonds and became an authorized distributor with the Argyle mine.

With a long history of buying and selling some of the most unique and historic diamonds in the world, Mathew brings a wealth of prestige, integrity and passion to the NCDIA as our Ambassador and spokesperson in Switzerland.

We are fortunate to have his participation as our representative.


We are happy to announce that we have appointed Marco Pocaterra to be the Ambassador for the Natural Color Diamond Association for Italy.

Marco is based in Milan and has deep knowledge of his home country. "Italy is the cradle of the arts of culture, of beauty and taste.

From my experience, Italy remains fertile for education and sales of fancy natural color diamonds. Having spoken to many jewelers across Italy, they still lack knowledge, experience and accessibility of natural fancy colors. Thus, their beauty and desirability are strongly underexposed to the public. The consequence is that Italian Jewelers do not create revenues with these extraordinary and incomparable gems. I am committed to help them inspire their customers and take the opportunity to have new attractive sales conversations."

Marco has spent the last 40 years working as an executive director in leading corporate banking, financial, insurance and real estate institutions. As an eclectic professional he also had experiences in the medical sector.

Marco has a deep experience of natural diamonds, which he acquired by working at the top of the industry, being adviser and partner with some leading international diamond companies for more than twenty years.

First a friend, he also shares my personal enthusiasm for the esthetics and allure of natural colors. His strong belief and demonstrated passion for our industry makes him an individual who inspires others. He will be a strong advocate for developing our visibility in Italy.


Mr. Yves Frey (Yves Frey Diamonds) remains our Ambassador in London, England and Mr. Henry Ho (Chairman of AIGS, Thailand) in Bangkok, Thailand. They continue as our spokespersons and add to our international prestige.

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