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Wednesday, October 29, 2014

Cutting the Blue Moon diamond

Suzette Gomes, CEO of Cora International, with the Blue Moon diamond on exhibit at the Museum of Natural History of Los Angeles County. Photo by E. Chamorro for NHMLA.

Did you check the Blue Moon diamond on display at Natural History Museum of Los Angeles County? You will see that we added the resin models of the different steps of the cutting process. Thanks to information provided by Cora International and the master cutter, here is the description our volunteer Brittany gathered. It is interesting to see the process of having an extremely valuable rough blue diamond and making a decision on how to cut it to yield the best color, clarity and shape. Enjoy!

The added resin models on display at the Natural History Museum of Los Angeles County. Photo by E. Gaillou for NHMLA.

The Blue Moon Diamond is one of the rarest diamonds in the world. Therefore the cutting process is a rather meticulous procedure. The rough diamond must first be placed into the hands of a master cutter. Most master cutters have been working in the trade for decades. The master cutter will examine the natural growth features of the rough diamond. From there, many models of the stone will be made. Creating models at every stage is a very important and significant part of the cutting process. These models give a blueprint to follow in creating this beautiful and extremely rare gem. Each model will be marked to determine the best shape and size of the stone. Once the model is marked, the cutter will begin to form facets into the model on the cutting wheel. 

Zoom in on the models. The numbers you read represent the carat weight of some steps of the cutting process.Photo by E. Gaillou for NHMLA.

The first two models created, weighing 22.79 cts, help determine the shape that would give the highest yield in weight and to also achieve an “Internally Flawless” diamond grade. One model was created in to a “square cushion” shape and the other in to a “long cushion” shape.

The Blue Moon diamond at 22.79 carats. © Cora International.

Now at 19.30cts, it was determined that the “longer cushion” shape would give a slightly higher yield in weight and more assurance to achieve the “Internally Flawless” grade.


The Blue Moon diamond on the cutting wheel. © Cora International.

The Blue Moon diamond at 19.30 carats. © Cora International.

The Blue Moon diamond at 19.30 carats. © Cora International.

At 16.31 cts the crown facets were preliminary blocked in and prepared for the shaping process. The results are examined and the model begins to take shape. Another replica model was created with pavilion facets at 15.29cts. This model determined how the deep indented naturals would be removed while retaining optimal weight and achieving an “Internally Flawless” clarity.

Once 14.21cts were reached, it was known that the gem had now achieved the “Internally Flawless” clarity grade. After achieving the final result on the model, the rough diamond was then able to be faceted on the wheel and polished into one of the rarest and most exquisite diamonds in the world.

The Blue Moon diamond at 14.21 carats. One already can see the beauty of the stone! © Cora International.

Wednesday, October 15, 2014

The making of the Blue Moon Diamond

In a short video produced by Cora International, here is the making of the Blue Moon Diamond, from the 29.6-carat rough to the 12-carat Fancy Vivid Blue, Internally Flawless gem. The Blue Moon Diamond is on display at the Natural History Museum of Los Angeles County until January 6, 2015. Come and see it: it is included in the regular entrance to the museum!


Tuesday, September 30, 2014

The Blue Moon Diamond: The Opening of the Exhibit


The Blue Moon Diamond, which we have been covering in the past few articles here and here finally has made it to our museum, welcomed by one of the largest museum events of the year. Both beautiful and scientifically significant, it has generated much buzz in both the general public and scientific community.

The day opened to great pizazz with a press conference at 9:30 AM, complete with a catered breakfast.

When the black cloth was pulled off, the diamond was presented to the press for the very first time.


Dr. Eloïse Gaillou and Suzette Gomes of Cora International answered questions about the history, production, and rareness of the Blue Moon diamond.

As readers of this blog will know, the diamond was mined in the Cullinan Mines of South Africa, a mine that has produced other famous diamonds such The Star of Africa and the Golden Jubilee. To learn more about those diamonds, click here. Knowing the source of the diamond is just as important as the chemical make up of the diamond itself.

Suzette presented the resin duplicates of the original 29.6 carat raw diamond, explaining the meticulous process of creating the rough to the polished final.

Edgar Chamorro © for NHMLA

The Blue Diamond's final size which stands at an impressive 12 carats, is especially notable for its flawlessness and color, which are much rarer at gems of this size.

Eloïse finished off the press conference with an interview by Channel 7.

There was no rest for the weary after the press event, however, because the official welcoming party would be taking place in a few hours. We had to set up and prepare and make sure everything ran smoothly. There was furniture to be arranged, flowers to place, lights to change, and general chaos that comes about when running events such as these.

The flowers were designed by Mille Fiori and were the centerpieces of each table.

Tiffany Arnolds © for NHMLA

Mario DeLopez © for NHMLA

There were two open bars at each corner of the foyer.

Mario DeLopez © for NHMLA

Setting up everything while not trying to run each other over was bit difficult.

Mario DeLopez © for NHMLA

Mario DeLopez © for NHMLA
But it was all very fruitful, because everything ended up looking great. Here's a shot of the museum's foyer with the decor all set up prior to the party.

Mario DeLopez © for NHMLA

The official party started at 7, and guests at the party entered from the north entrance, where they were checked in by these lovely ladies, the work study students and interns of the Gem and Mineral department.



Directly in front of the table were two photos of the eponymous diamond. One was a normal photo of the diamond, but the Blue Moon has the rare qualities of glowing red after exposure to ultraviolet light (phenomenon called phosphorescence). To read more about specifically why it is glows red, read here. This rare phenomena of the Blue Moon diamond has been an important facet of Dr. Eloïse Gaillou's work and a large reason why this diamond is so important.

Tiffany Arnolds © for NHMLA
In addition to the two open bars, and servers walked around with Veuve-Cliquot champagne and trays of hors d'oeuvres.

Tiffany Arnolds © for NHMLA

The food was catered by Heirloom LA., a catering company that also owns a host of food trucks in LA.

Unfortunately we have no photos of the main appetizers but I can personally vouch that it was really good. We do have photos of the desserts, which were a hodgepodge of different remakes of classic American desserts.

Mario DeLopez © for NHMLA
On this plate, we have some fancy blueberry cookies, Strawberry and pear poptarts, s'mores officially named Blueberry Crostata, Seasonal Pie Squares, and Inside Out S'mores.

About halfway through the party, Eloïse gave a speech on the scientific importance of the Blue Moon and thanked Suzette Gomes for loaning the Blue Moon to the Natural History Museum of Los Angeles County.

Mario DeLopez © for NHMLA

Alan Bronstein, owner of the Aurora Butterfly and Aurora Gems, gave some background of diamonds. A lot of Eloïse's work is thanks to the material (diamonds!) support of Aurora Gems, and his butterfly has been a wonderful temporary exhibit to the Gem and Mineral Hall.

Mario DeLopez © for NHMLA

Jim Shigley, Research Fellow at GIA talked about the certification for the color of the Blue Moon, which was graded a fancy vivid, the best color rating for a diamond.

Mario DeLopez © for NHMLA
Here are some final shots of the presentation, which also had a video playing about the making of the diamond and the studies conducted at the Smithsonian.

Mario DeLopez © for NHMLA
Mario DeLopez © for NHMLA

The entire Gem and Mineral Hall was transformed for the night as well.

The Hall was decked out in colorful lights, almost completely unrecognizable. There was a rope that led the crowd directly to the Gem Vault, so one couldn't get lost on the way.


Mario DeLopez © for NHMLA

A gobo projection displayed the name of the diamond on the back wall of the gold exhibit.


Mario DeLopez © for NHMLA

Blue lights streamed out from the gem vault, filling the hallway with lighting not unlike a club scene, only much better because there was a diamond at the center of it all.

Mario DeLopez © for NHMLA

Mario DeLopez © for NHMLA

As for the diamond itself, it remained in its glass case, dazzling all with its size, brilliance, and color.

For fun, we had a photographer on site, photographing guests with the gem.

Mario DeLopez © for NHMLA

Mario DeLopez © for NHMLA
Many guests took their own photos of the Blue Moon.

Mario DeLopez © for NHMLA
And here is the diamond itself.

Edgar Chamorro © for NHMLA

Our Gem & Mineral Council members were among the guests for this special event. We can affirm that everybody present had a fab time! The diamond will continue dazzling visitors at the Natural History Museum of Los Angeles County until January 6th. Come and see it for yourself: you can see the diamond with your regular museum entrance (or for free with your museum membership).



Monday, September 1, 2014

Testing the Blue Moon Diamond at the Smithsonian

The Blue Moon Diamond, a 12-carat Fancy Vivid Blue diamond, on display at NHM. Photo by Tino Hammid for Cora International.

Beginning September 13, 2014, we will have a very special host in the Gem Vault of our Natural History Museum of Los Angeles County: The Blue Moon Diamond will be on display until January 6, 2015. The 29.6 ct rough diamond was found back in January 2014 at the Cullinan Mine in South Africa. Cora International purchased it in February and had it cut in a spectacular 12 ct cushion. The faceting of the stone took place from April to the end of June in New York.

First of all, I wanted to emphasize our interest to have such a stone at our museum. Of course, there is the exhibit point of view. What a great opportunity for our public to be able to see a big blue diamond. Yes, 12.03 ct (2.4 grams) is impressive for a blue diamond. They are much, MUCH rarer than colorless diamonds (called "white diamonds" in the market). They are probably some of the rarest of all the gems. This diamond has been graded by the Gemological Institute of America (GIA) Fancy Vivid Blue diamond, with an IF (internally flawless) quality. The cut is perfect. All of these qualities make it a gem as rare as "once in a blue moon", phrase from which its name comes from.

Now, in the scientific point of view, this diamond might be even more exceptional! I have been studying blue diamonds for over 5 years now, mostly when I was a post doc at the Smithsonian Institution. I had the chance to study famous stones such as the Hope diamond, the Wittelsbach-Graff or the Blue Heart diamonds for example. All in all, it's over 100 blue diamonds that I have analyzed. But most of them were less than one carat, and only a few were of known origin (a dozen only). And they are so rare that we had to find ways to borrow some diamonds for our study. If a few came from the National Gem & Mineral collection, most came from private parties. Aurora Gems for example loaned to us over 3/4 of the stones studied. We are thankful that Cora International agreed to let us conduct some (non-destructive!) analyses on the diamond, and also supported me to go to the Smithsonian to acquire the necessary data.

Why blue diamonds are so special? As explained in a previous blog post, their color comes from the element boron. First interesting fact: boron is quite rare deep in the Earth, where diamonds form (in the Earth Mantle, some 90 miles below the Earth surface or deeper!). Boron is a light element and is expected to be found mostly at the surface of the Earth, or not far below. So, where does the boron contained in the rare blue diamonds come from? Was it in the Earth Mantle since the formation of the Earth? Or was it pushed deep inside the Earth through plate tectonics, by convection of a subducting oceanic plate?
Also, we know that boron gives the blue color of a diamond. But does the amount of boron directly correlates with the intensity of the blue color? Blue diamonds have the property of phosphorescing (emitting a color after exposure to an ultraviolet light - also called black light-). Most emit a very short bluish phosphorescence, while a few emit a orange-red glow. What physical phenomenon controls that?

In this blog post, I'll show you a few pictures of the Blue Moon diamonds acquired while we were conducting the experiments at the Smithsonian Institution, in the highly secured "Blue Room", in the Mineral Sciences department. But look forward to an article talking about the actual results in the coming months!
The scientists present during the experiments were: Dr. Jeff Post, Curator and Dr. Keal Byrne, postdoc, both from the Smithsonian Institution; Dr. Jim Butler and myself.

The arrival of the Blue Moon Diamond and its unpacking by Jeff Post.

Waiting to discover the stone we long expected to see!

Far from being a professional picture, our first look at Blue Moon Diamond. There were a lot of "wow" in the room when Jeff opened the package.

The Blue Moon Diamond and the phosphorescence equipment on the background. 

The diamond is now in place to be analyzed. The metallic wire is a fiber optic that conducts the ultraviolet (UV) light and receives the light emitted by the stone. 

A close-up of the experiment: we analyzed several spots on the stone to see if the diamond was emitting similar phosphorescence everywhere.

Jim preparing a cover for the experiment!

There is nothing to see anymore: the diamond is fully covered to be in the dark during the experiment.

Keal and I doing the last tests before running the phosphorescence experiments. Photo by Jeff Post.

What is it that we are doing when we run a phosphorescence experiment? As Jeff shows to the film crew, it's similar to exposing the diamond to a UV light for 20 sec, turning the UV light off and looking if the stone emits a light and if so, what color light. However, our eyes are not as sensitive as a spectrometer is, that is why we use this machine on top of the visual examination.

A very surprising result: the Blue Moon Diamond phosphoresces orange-red for about 20 seconds, while most blue diamonds show a short bluish phosphorescence. Only a few other diamonds have such a reddish glow, we will cite the Hope diamond and the Wittelsbach-Graff for which the phosphorescence lasts a minute! Amazing photo by Tino Hammid for Cora International.

The exact reason for the long red versus short bluish glow is not perfectly understood. That is also why we continue acquiring data on more blue diamonds. It might involve the boron defects present in the structure of diamond, interacting with other impurities, defects or charge imbalance. So far, the Blue Moon diamond is the only diamond known coming from South Africa that shows a red glow. The other diamonds of known locality showing the red glow were coming from India (such as the Hope diamond or the Wittelsbach-Graff).

We also conducted some experiments with a Fourier Transform infrared (FTIR) spectrometer. With this machine, we can see the signal of the carbon atoms interacting with each other, as well as the signal of the possible other impurities. Photo by Jim Butler.

Getting some signal through a faceted stone is not the easiest! But we got some good results. Photo by Jeff Post.

Our FTIR analyses confirmed the presence of the element boron as an impurity, which is the source of the color. The Blue Moon Diamond is therefore classified as a Type IIb diamond (no nitrogen impurities visible by FTIR, but boron impurities present). We will be able to quantify the amount of boron thanks to the spectra acquired. Stay tuned!


Finally, we were curious to look at the remaining strain inside the diamond structure. All natural diamonds show some strain features, and the Blue Moon is no exception. The colored striations are the evidence of such a strain. Photo: Eloïse Gaillou, in between cross-polarizers.

Again, they are not professional pictures, but I still wanted to end with a few shots that I took while conducting the experiments at the Smithsonian. You will have to come to NHM Los Angeles and see for yourself to get the true experience of the color and the fire of the Blue Moon! Photo below and above: Eloïse Gaillou.



All photo credit: Eloïse Gaillou, unless otherwise mentioned.