Tag: Brazil Diamonds

This rough diamond hints at oceans’ worth of water inside Earth

Photo credit: University of Alberta

A $20 diamond provides evidence of a ‘wet zone’ deep below Earth’s surface where vast volumes of water are locked up inside minerals.

It might be the ugliest diamond you’ll ever see, but within this brown sliver of carbon is a gem of a find for a University of Alberta scientist working to unravel an ocean-sized mystery deep beneath the Earth.

An international team of scientists led by Graham Pearson, Canada Excellence Research Chair in Arctic Resources at the U of A, has discovered the first-ever sample of a mineral called ringwoodite. Analysis of the mineral shows it contains a significant amount of water—1.5 per cent of its weight—a finding that confirms scientific theories about vast volumes of water trapped 410 to 660 kilometers beneath the Earth, between the upper and lower mantle.

“This sample really provides extremely strong confirmation that there are local wet spots deep in the Earth in this area,” said Pearson, a professor in the Faculty of Science, whose findings were published March 13 in Nature. “That particular zone in the Earth, the transition zone, might have as much water as all the world’s oceans put together.”

Image credit: University of Alberta

Ringwoodite is a form of the mineral peridot, believed to exist in large quantities under high pressures in the transition zone. Ringwoodite has been found in meteorites but, until now, no terrestrial sample has ever been unearthed because scientists haven’t been able to conduct fieldwork at extreme depths.

Pearson’s sample was found in 2008 in the Juina area of Mato Grosso, Brazil, where artisan miners unearthed the host diamond from shallow river gravels. The diamond had been brought to the Earth’s surface by a volcanic rock known as kimberlite—the most deeply derived of all volcanic rocks.

“One of the reasons the Earth is such a dynamic planet is because of the presence of some water in its interior,” Pearson said. “Water changes everything about the way a planet works.”

The discovery that almost wasn’t

Pearson said the discovery was almost accidental in that his team had been looking for another mineral when they paid about $20 for a three-millimeter-wide, dirty-looking brown diamond. The ringwoodite itself is invisible to the naked eye, buried beneath the surface, so it was fortunate that it was found by Pearson’s graduate student, John McNeill, in 2009.

“It’s so small, this inclusion, it’s extremely difficult to find, never mind work on,” Pearson said, “so it was a bit of a piece of luck, this discovery, as are many scientific discoveries.”

The sample underwent years of analysis using Raman and infrared spectroscopy and X-ray diffraction before it was officially confirmed as ringwoodite. The critical water measurements were performed at Pearson’s Arctic Resources Geochemistry Laboratory at the U of A. The laboratory forms part of the world-renowned Canadian Centre for Isotopic Microanalysis, also home to the world’s largest academic diamond research group.

The study is a great example of a modern international collaboration with some of the top leaders from various fields, including the Geoscience Institute at Goethe University, University of Padova, Durham University, University of Vienna, Trigon GeoServices and Ghent University.

For Pearson, one of the world’s leading authorities in the study of deep Earth diamond host rocks, the discovery ranks among the most significant of his career, confirming about 50 years of theoretical and experimental work by geophysicists, seismologists and other scientists trying to understand the makeup of the Earth’s interior.

Scientists have been deeply divided about the composition of the transition zone and whether it is full of water or desert-dry. Knowing water exists beneath the crust has implications for the study of volcanism and plate tectonics, affecting how rock melts, cools and shifts below the crust.

Article Published in 2014 – March – Courtesy of Earthsky.org

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Industry News: Buyer Beware – Green Diamonds

Image courtesy of Reuters -  Philimon Bulowayo

Image courtesy of Reuters – Philimon Bulowayo

Wholesalers have to be extra cautious when dealing in green diamonds or risk violating U.S. sanctions against Zimbabwe.
By Shaun Sim of Rapaport

Wholesalers attending a seminar at the Natural Color Diamond Association (NCDIA) in NewYork City expected to find out whether Zimbabwe green diamonds bearing Kimberley Process (KP) certification made them legal to trade. Instead, they learned that U.S. sanctions against the country made all diamonds from Zimbabwe not just the green off limits, regardless of whether or not they were KP certified. As the majority of the country’s diamond production came under Mugabe’s control, the sanctions effectively stopped diamond trading between Zimbabwe, the EU and the U.S. About ten years later, the EU, pushed by Belgium, lifted the bans on Zimbabwe’s diamond mining firms. However, the U.S. kept its sanctions in place.

In 2003, then-President George W. Bush signed an executive order for economic sanctions against Zimbabwe President Robert Mugabe, other individuals and companies. The sanctions were a response to the human rights violations by the Mugabe government, suspected money laundering and alleged funding of terrorist activities. Around that time,the European Union (EU) had imposed similar sanctions against Zimbabwe.

As the majority of the country’s diamond production came under Mugabe’s control, the sanctions effectively stopped diamond trading between Zimbabwe, the EU and the U.S. About ten years later, the EU, pushed by Belgium, lifted the bans on Zimbabwe’s diamond mining firms. However, the U.S. kept its sanctions in place.

Many seminar attendees asked speakers Cecilia Gardner, president,chief executive officer (CEO) and general counsel of the JewelersVigilance Committee (JVC),and Tom Gelb, educational director of NCDIA, what they could do to protect themselves.“The first thing is to ask for a certificate,” said Gardner. The onus is on the buyer to make sure that

not only is the green diamond KP compliant,as the U.S. is a member of the agreement, but that the buyer should also ensure that the stone did not come from Zimbabwe.

RARE BUT INCREASINGLY POPULAR

Green diamonds are exceedingly rare. According to Gelb, Zimbabwe accounts for as much as half of global green diamond production.There has also been a dramatic increase in production because of increased activity in Zimbabwe’s Marange region. Guyana and Brazil are the other large producers of green diamonds.

Green diamonds started to take off in late 2014, when celebrities were seen sporting emeralds on the red carpet. “Diamond dealers started thinking that if emeralds were popular,why not green diamonds? We started having people asking us where to source for green diamonds and for the price range,” said Gino Di Geso, director of NCDIA.

Over time, industry players became aware of the issues involved in dealing in green diamonds: Namely, the fact that green diamonds were likely to have come from Zimbabwe and that they were illegal.“NCDIA members would ask,‘Are we allowed to deal with these goods?’and ‘Are they okay if they were KP certified?’”said Gelb, adding that the members mostly asked about the KP process. He said that knowledge of the U.S. sanctions against Zimbabwe was scant.“You have to go searching for it to even know about it,” said Gelb.

HARSH PENALTIES

Many dealers did not know about the consequences of possessing Zimbabwe green diamonds.“I sort of knew about the issues concerning Zimbabwe and I knew about the sanctions, but the seminar showed me the details of the regulation,” said attendee Ishay Ben-David, owner of Ishay Ben-David Corp., a wholesaler of natural colored diamonds. The seminar explained that the U.S. government could do what is called a“claw back,”where the government could simply go into a dealer’s bank account and take money out of it for the value of the diamond or profits derived from the sale of it.The government could also indict an individual for criminal conduct or sue civilly for violating sanctions,according to Gardner.

Wholesalers were not pleased to learn how easy it was to fall afoul of the law.“It seems that there is not much you can do to protect yourself,” said Kushal Sacheti, CEO of Galaxy USA Inc. in NewYork City.“The law is so vaguely defined and nobody can prove or disprove if a diamond is from Zimbabwe,”he said.

Once a diamond is cut,it is very hard to prove its origins. Furthermore,as green diamonds receive their color from radiation, which penetrates the stone to varying depths, it is possible for a green diamond to end up appearing like a D flawless stone when cut and polished, making it difficult to pinpoint its origin, said Gelb.

This presents a problem for traders, who only have the guarantee from sellers that their diamonds did not originate in Zimbabwe. “The government, which is tracking these stones, knows they are from Zimbabwe but we don’t,” said Sacheti.“Even if we ask and are told they are not from Zimbabwe, if they end up being from Zimbabwe, there’s nothing we can do.”

Some wholesalers believe that their experience helps them identify Zimbabwean green diamonds.“They have a sort of grayish yellow tint to them,” said Ben-David. However, Gelb felt that such anecdotal practices are not foolproof. “This may be the standard practice for diamond dealers, but from the point of view of science, any diamond that came from Zimbabwe could certainly look like it could have come from some where else,”hesaid.

RISKY MARKET AHEAD

Currently, the availability of green diamonds is still so low that it remains mostly a collector’s market, though that might change in the future.“It is certainly the fastest- growing color aside from pink and blue,” said Di Geso.

While demand for that color grows, the politics hanging over Zimbabwe diamonds are not likely to change in the near future, according to Gardner. “The Zimbabwe government hasn’t really changed much,”she said.“I guess we just have to be extraordinarily careful,” concluded Sacheti. ✦.

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