“A Talk with Hanco Zwaan”, PhD in gemmology and mineralogy, Director of the Gemmological Laboratory of The Netherlands

August 20, 2010 | 4 Comments

“Emeralds have always been my favorites”

This time I have the great honour to introduce you to Hanco Zwaan, Director of the Netherlands Gemmological Laboratory (NEL), Curator of the mineralogy department of Naturalis (the National Museum of Natural History in The Netherlands ) and gemmological researcher.
For those who have never heard of Hanco Zwaan before; He’s a true world-wide authority for his research on Emerald, specifically the emeralds of Zambia and Zimbabwe. An impressive gemmologist, with an unique job that allows him to enjoy all facets of gemmology; from creating exhibitions, testing gemstones for  private persons & trade as well as doing research in the field followed by publishing articles of the highest scientific level.  
I would like to quote Hanco; “Gemstones are special minerals created by special and often unique processes in the earth’s crust. I’m interested in developing models of these fascinating processes by unravelling the geological history in a particular gem-bearing area. Therefore Emeralds are so highly interesting. For instance African emeralds come from very old Precambrian deposits, and they still occurs “in situ”, that is in the original place where they were actually formed. These deposits are therefore very suitable for study of the emerald’s origin in contrast to alluvial gem deposits in which minerals and rocks occur that have been weathered transported and deposited as a result of river action”.
As a gemmological researcher he wrote an impressive list of publications covering a wide range of gemstones. You can view the list at this link (and scroll).

In the spring of 2009 he won the  “Dr. Edward Gübelin Most Valuable Article Award 2008”! with the “Copper-bearing Tourmaline from Mozambique” article, chosen as most valuable article by the readers of “Gems & Gemology”, the most important international gemmological journal.

Why specifically did you win this prize & can you tell something about it?
It was the right timing for this specific gemstone!
These Copper-bearing tourmalines from Mozambique show beautiful bright and vivid colours, resembling the well known “Paraíba” tourmalines found in Brazil. A fair amount of  large clear crystals  came from this new location (known since 2001). They fetch good prices, but are relatively cheap in comparison to the “Paraíbe tourmalines” from Brazil, this might be due to the fact that in the case of Mozambique the colours may generally be slightly lighter. 
The Brazilian mines of this primary source of copper-bearing tourmalines are virtually depleted. So it may be a matter of time and then Mozambique (and Nigeria) will take over this position.
The unique thing of the copper-bearing tourmalines is that the colours are so impressive and clear! They are really unbelievably sparkling violet to “neon” blue, pink to purple & green to yellowish green.
I went with American colleagues to Mozambique and studied the geology. We also took samples for investigation in the laboratory. We treated these samples by heating, a very common technique to improve the colour, and listed the changes in colours and clarified what exactly happens during that process. All this is extensively described in the article which you can download (not completely  for free) at the site of the GIA. (The link made above)

Can you tell something about the series “Gem Session” on this blog? 
Well, while we were talking about this “Talk” it became clear that there’s so much to tell and so much to link you through on the Internet that it would be just too much for one article. Therefore the idea came-up to start a mini series  for the next coming half year called “Gem Session”, starting this autumn. In these sessions we try to cover many issues concerning gems. The topics will be very diverse; fair trade in the coloured gemstone industry, pearls, enhancement methods, gemmological tools, courses & societies as well as some other topics.

Hanco’s book recommendation is:

“Emeralds A Passionate Guide”, by Ronald Ringsrud, $80. More information of this book you can find at Emeraldpassion.com

You can read, download is not for free again, the book review written by Hanco Zwaan at the web-site of GIA, “Gems & Gemology, Vol. 45, No.4, pp. S2-S4, 2009.

 Of course his museum  recommendation is Naturalis; “His home base”! Since the gems are new on display again and the exhibition is spectacular! Showing faceted gemstones next to the original rough crystals.

This article is published by the courtesy of Hanco Zwaan.


4 Responses to ““A Talk with Hanco Zwaan”, PhD in gemmology and mineralogy, Director of the Gemmological Laboratory of The Netherlands”

  1. Margriet Sopers
    November 16th, 2010 @ 10:39 am

    Hi Michael,
    Thank you for your reply! Hopefully you will like the coming “gem sessions” as well. But it’s a lot of work, so you’ve got to wait a little while. Nevertheless, I’m working on it!
    By the way, where are you coming from?

    Kind regards,

  2. Margriet Sopers
    August 7th, 2011 @ 8:34 pm

    Dear Nisha,
    Of course you are able to study for a Phd in gemmoly/mineralogy, but perhaps a Diploma of GIA or FGA would fit better for your career in the family business. GIA & FGA are the worldwide known for their studies and quality. I would advice you to take a look at their studies.
    If you would like to come in contact with these institutes please go to my website again and look for ‘education’followed-up by the article ‘Institutes and laboratories’. Here you will find the direct links to their websites. They both have very interesting websites and ‘contact’ posibilities for all your questions. I’m convinced there will be a solution to study in India for their worldwide known courses.

    Kind regards,
    Margriet Sopers

  3. Margriet Sopers
    September 2nd, 2011 @ 2:24 pm

    Dear Michael,

    I just wanted to let you know ‘Gem Session 2’, about pearls & conch pearls, is on my blog…and with beautiful links again!
    Enjoy it!

  4. Margriet Sopers
    February 25th, 2012 @ 9:52 pm

    Dear Zahari,
    Where do you come from/liveright now? There are several options worldwide.

    Kind regards,

    Margriet Sopers

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Margriet Sopers

Margriet Sopers, FGA

Having a diploma in jewellery, FGA and a propaedeutic of the Academy of Art followed-up by interesting years as a jewellery expert at Sotheby's & Gemeentelijke Krediet Bank, as well as being a member for years of the Society of Jewellery Historians, I am glad to share with you today's world of jewellery.

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