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! Photo by Tino Hammid (slightly enhanced to better show the glow) 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, therefore source of the color. 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.




Saturday, August 30, 2014

A SPECIAL DIAMOND EXHIBIT AT NHM Los Angeles, running through January 6, 2015

The reunion of exceptional diamonds

Beginning September 13, 2014 and until January 6, 2015, we will have a special reunion of diamonds at NHM: The Blue Moon Diamond will meet the Butterfly of Peace diamond collection. The collection of 240 natural fancy-colored diamonds that make the spectacular Aurora Butterfly of Peace is already worldwide renown and well traveled: it had been on special exhibits at the Smithsonian Institution and at the Houston Museum of Science, just to cite only a few of the prestigious places it has seen. The Butterfly of Peace will have a new companion beginning September 13: The Blue Moon Diamond, which was recently discovered in South Africa. Now faceted from the 29.6-carat rough, the 12-ct stone will also be displayed in the Gem Vault of the Natural History Museum of Los Angeles County.

The renown Aurora Butterfly of Peace: 240 natural fancy-colored diamonds. All known colors of diamonds are represented in this unique and exceptional collection totaling 167 carats of beauty. The collection is not only a delight for the public but also for the scientists to study. The variety of colors makes it the best tool to analyze the color in diamonds. On loan from Aurora Gems. Photo by Robert Weldon. Copyright: GIA.

The 12-carat Fancy Vivid Blue Moon Diamond. Recently discovered in South Africa, this diamond shows the most exquisite of the blue colors. Such as the Butterfly of Peace diamond collection, the Hope diamond, or the Wittelsbach-Graff, it was studied at the Smithsonian Institution before coming on exhibit to our museum. On loan from Cora International. Photo by Tino Hammid. Copyright: Cora International.


The Aurora Butterfly of Peace on exhibit at NHM


Add 240 fancy-colored diamonds, the rarest of all the gems. Arrange it carefully in a butterfly shape that took the owner (Aurora Gems) over 10 years to put together. Obtain a delightful art-piece that will be a joy for the public and the connoisseur to look at!

The Aurora Butterfly of Peace on exhibit at NHM. Photo and copyright: K. Stone.

The Aurora Butterfly of Peace as seen on its display case. Photo and copyright: E. Gaillou for NHM.

A different look at the Butterfly of Peace! Photo and copyright: E. Gaillou for NHM.

I would like to quote my colleague George Harlow from the American Museum of Natural History (AMNH): when the Butterfly of Peace was on exhibit at the AMNH, he mentioned that their colored diamond exhibits have “the highest slobber factor of anything in the gem house” with “nose prints and handprints” commonly found on the glass. We would concur with that! Good thing that our display cases are cleaned every morning...

The Blue Moon Diamond: from rough to cut


The 29.6-carat rough stone was unearthed at the Cullinan Mine in South Africa by Petra Diamonds in January 2014. In February, Cora International bought it and began the cutting process in April 2014. The cut stone was finished at the end of June. The photos below show you a few steps of the cutting process from the rough to the cut stone. Before cutting the blue stone, models of it were made and cut. No rough stone is perfect to begin with, and inclusions and impurities have to be avoided during the cutting process so that the cut stone doesn't have any inclusion in it. The design of the stone was so well done that the stone has been graded "Internally Flawless" by GIA.

The rough 29.6-carat Blue Moon Diamond on the cutting wheel. Copyright: Cora International.

The first "window" is open in the diamond. It is from this first facet that the other ones will be built from. Copyright: Cora International.

More facets are polished. Isn't it scary to see such a valuable diamond in such position?! Copyright: Cora International.

Some of the front facets are polished, while the back of the Blue Moon is still rough. Copyright: Cora International.

The Blue Moon diamond on the cutting wheel. Copyright: Cora International.

Almost there! But still a few more facets to be cut on the back of the stone. Copyright: Cora International.

On this shot, we already can see the finished shape of the stone. It begins to look like a little brother of the Hope diamond!

The Blue Moon Diamond will be on display in the Gem Vault of the NHM from September 13, 2014 until January 6, 2015, next to the Butterfly of Peace diamond collection. It will most likely be the ONLY public appearance of this diamond, so rush in! Especially that you can see this special reunion of exceptional diamonds with a regular NHM admission.

On view at:
900, Exposition Bvd
Los Angeles, CA 90007
(213)-763-3466

Tuesday, July 8, 2014

Sainte-Marie-aux-Mines Gem & Mineral Show 2014

Poster and specimen advertising the 2014 Sainte-Marie show. Cuprite on atacamite from Bisbee, Arizona, USA (Graeme family collection).

This year, I was again invited by the organizers to participate in the world-wide renowned Sainte-Marie-aux-Mines Gem & Mineral Show, open to the public June 26-29, 2014. Sainte-Marie is located in the department of the Haut-Rhin, in the picturesque Vosges Mountains, north-east region of France. The Sainte-Marie show is the mineral show with the best atmosphere (in my opinion): the people, the place, the food and the drinks make it extremely convivial and welcoming, even for non-French speakers. The entire town is turned inside out to welcome its visitors. The local librarian will even be pouring you wine at the town party!


This year, I have to admit that I didn't have much time to tour around to look at rocks. Busy schedule: four lectures to give and some filming for "What's Hot in Sainte-Marie". I mostly focused on the special "Prestige" exhibit on Copper, on my first day at the show, before it was open to the public.

About to enter a silver mine in Tellure, for "What's Hot in Sainte-Marie". Photo credit: Bryan Swoboda.

I am here giving a lecture on "Diamond and its extraordinary genesis", during the Sainte-Marie show. Photo credit: Alan Hart.


"Expo Prestige": Copper Exhibit


In a dedicated room, the Copper Exhibit presented hundreds of copper-bearing minerals, on loan from museums and private collectors. Most museums displaying are European (MNHN in Paris, Natur Musée in Luxembourg, Musée des Confluences in Lyon, Mines ParisTech, to cite a few); but for the first time this year, the Mineralogical and Geological Museum of Harvard University was also represented. Let's not forget to mention some private collectors, such as the Graeme family, who had their cuprite being the star of the show (see the first picture of the blog) and also Alain Martaud (who was in charge of selecting the minerals for the exhibit),  Gilles Emringer and Valère Berlage.


The "Prestige" copper exhibit: photo taken during the installation.

Copper exhibit: photo taken on the opening day.


Below is only a small selection of the minerals displayed. They are more on this Facebook page (click here), even if again, it's only showing my personal favorites! I was extremely impressed by all these French copper minerals reunited, especially the ones coming from Chessy-les-Mines (Rhône). They are not specimens that American collectors see very often, or that I've seen in such quantity and quality... and most likely, it's the first time that such an exquisite selection has been put together. So... Enjoy!


Copper-bearing minerals from Chessy-les-Mines (Rhône, France)


Lovely suite of azurite from Chessy-les-Mines, Rhône, France. G. Emringer collection.

Malachite after cuprite from Chessy-les-Mines, Rhône, France. G. Emringer collection.

Another suite of malachite after cuprite showing different morphologies, from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Zoom on a malachite after cuprite from Chessy-les-Mines, Rhône, France. G. Emringer collection.

Malachite after cuprite in an ancient box, from Chessy-les-Mines, Rhône, France. Mines ParisTech collection.

Malachite after cuprite on azurite from Chessy-les-Mines, Rhône, France. G. Emringer collection.

Malachite after cuprite on azurite. A. Martaud collection.

Malachite on azurite from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Azurite and malachite half nodules, from Chessy-les-Mines, Rhône, France. MNHN collection.

Azurite and malachite from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Great association of large azurite crystals with malachite and baryte, from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Loving the old label! Azurite and malachite from Chessy-les-Mines, Rhône, France. J.-F. Lanoe collection.

Azurite from Chessy-les-Mines, Rhône, France. MNHN collection.

Azurite from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Azurite from Chessy-les-Mines, Rhône, France, featured in Lacroix's book. MNHN collection.

One of my favorites! Azurite from Chessy-les-Mines, Rhône, France. Mines ParisTech collection.

Azurite from Chessy-les-Mines, Rhône, France. Mines ParisTech collection.

Stalactite of malachite coated with azurite from Chessy-les-Mines, Rhône, France. MNHN collection.

Stalactite of azurite on azurite from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.

Azurite from Chessy-les-Mines, Rhône, France. Musée des Confluences collection.


Copper-bearing minerals from other localities in France


If Chessy-les-mines is the main French locality for amazing copper minerals, let's not forget some others.

First, let's not forget the copper minerals from Sainte-Marie-aux-Mines! This is a chalcopyrite from Sainte-Marie, Haut-Rhin, France. MNHN collection.

Another chalcopyrite from Sainte-Marie, Haut-Rhin, France. G. Emringer collection.

This malachite on quartz comes from Bouch-Peyrol, in Aveyron, France. A. Martaud collection.

Chalcopyrite from Cuzac, Lot, France. A. Martaud collection.

Azurite and malachite on sandstone from Gaillot, Lot, France. A. Martaud collection.

Quartz, malachite and chalcopyrite from La Gardette, Isère, France. G. Emringer collection.

Tetraedrite from La Mure, Isère, France. A. Martaud collection.

Tetraedrite from Oisans, Isère, France. MNHN collection.

Chalcopyrite from Laguepie, Tarn-et-Garonne, France. A. Martaud collection.


Copper-bearing minerals: worldwide


Let's not be too chauvinistic and let's take a tour around the world to discover some fabulous copper minerals! My dioptase pictures were pretty bad, so I will be only sharing one.

Azurite and malachite from Kerouchen, Morocco. P. Morelon collection.

Azurite and malachite from Bouskour, Morocco. MNHN collection.

Malachite and azurite from Touissit, Morocco. P. Morelon collection.

Azurite crystals from Kerouchen, Morocco. P. Morelon collection.

Tetraedrite from Mouzaia, Algeria. MNHN collection.

Large crystal of azurite with malachite pseudomorph from Tsumeb, Namibia. MNHN collection.

Another large crystal of malachite completely pseudomorphed into malachite, from Tsumeb, Namibia. MNHN collection.

Native copper from Tsumeb, Namibia. Mines ParisTech collection.

Cuprite pseudomorphed into malachite from Onganja, Namibia, with its crystallographic wood model. Natur Musée collection. 

Azurite with chalcoalumite from Lyon County, Nevada, USA. Mines ParisTech collection.

Native copper from Houghton County, Michigan, USA. Harvard collection.

Azurite and malachite from Bisbee, Arizona, USA. Harvard collection.

That slice is super fun, geologically speaking. It's a breccia made of azurite cement! It comes from Morenci, Arizona, USA. Museum national d'Histoire naturelle (MNHN) collection.

Chalcopyrite from Matamoros, Durango, Mexico. Mines ParisTech collection.

Clinoclase from Cornwall, England, still mounted on its early 19th century base and hand written by Henry Just Haüy. MNHN collection.

Quartz on chalcopyrite from Redruth, Cornwall, England. Mines ParisTech collection.

Tetraedrite from Herodsfoot, Cornwall, England. MNHN collection.

Cuprite from Rheinbreitbach, Westerwald, Germany. Natur Musée collection.

Pseudomalachite and libethenite from Nijne Tagilsk, Ural Mountains, Russia.

Native copper from Kolwezi, Katanga, Democratic Republic of Congo. Natur Musée collection.

Large specimen of malachite from Mashamba West, Katanga, Democratic Republic of Congo. Natur Musée collection.

Native gold on malachite and digenite from Musonoi, Katanga, Democratic Republic of Congo. Natur Musée collection.

Malachite and chrysocolla from the Etoile mine, Katanga, Democratic Republic of Congo. Natur Musée collection.

Quartz on shattuckite from Tantara mine, Katanga, Democratic Republic of Congo. V. Berlage collection.

Dioptase from Tantara mine, Katanga, Democratic Republic of Congo. This photo doesn't give it justice, sorry! Natur Musée collection.

Cornetite from Etoile mine, Katanga, Democratic Republic of Congo. Natur Musée collection. 

Malachite on bright pink cobaltocalcite from Musonoi, Katanga, Democratic Republic of Congo. Natur Musée collection.

Cuprite from Mashamba West, Katanga, Democratic Republic of Congo. Natur Musée collection.

Shattuckite from Tantara Mine, Katanga, Democratic Republic of Congo. V. Berlage collection.

And to close the exhibit: Bryan Swoboda (left), Raquel Alonso-Perez and Alain Martaud.

Around the show

Let's walk around the show, see the setting, the people, and the great party thrown by the show organizers for all the dealers and special guests. Another great time in Sainte-Marie, even with rain on Saturday morning and Sunday. 

Upon my arrival, on the evening of Tuesday 24, June, I met up with some friends and colleagues, reunited around a drink to watch the Italian playing football against Uruguay (I mean, proper football, not American football). Even some Americans joined! The Sainte-Marie show was happening at the same time as the second week of the world cup, the teams were playing their qualifying game for the round of 16.

Our American friends drinking beer and eating foie gras (yes... really?!).

Italians and Frenchies watching the game. Let's not remind our Italian friends what the score was. Notice the empty plates... of foie gras.

First night at the show in good company! Wanted again to thank our friends from the MNHN to have gathered a few of us together for this great night.


I got the chance to take a few pictures before the show opened to the public, on Wednesday 25, June. The weather was gorgeous, which was a good thing when carrying rocks around.
Set up time at the Mineral Show.

Almost ready. In the background, the theater at the Mineral Show.

Mineral Show, ongoing.
On the opening day, Friday June 26th, the crowd was present and queuing for tickets and to enter the show. Another successful year for the Sainte-Marie show!

As I was mentioning earlier, I didn't get many pictures of minerals during the show. From what I saw, the mineral that got people talking was the new find of plumbogummite, sometimes associated with pyromorphite, from China (Yangshuo Mine, Yangshuo County, Guilin, Guangxi Zhuang). Some specimens were really aesthetic. Renée Daulon and Jordi Fabre had some, but the most spectacular one was Christophe Gobin's, combining the blue-green color of plumbogummite with the intense yellow of the pyromorphite. Sorry, I didn't get any pictures!

I got a few pics of some other fun minerals, mostly from dealers set up in the theater:

Overview of the theater.

Jean-Michel Laverrière had some fun beryl crystals from Dassu Valley, Baltistan, Pakistan with magnificent inclusions, such as manganotantalite above and schorl below.

Crystal Classics, as usual, had some sexy specimens, such as this reticulated cerussite from Nakhlak Mine, Madan-e Nakhlak, Anarak District, Nain County, Esfahan Province, Iran.

or this triple crystal of tanzanite from Tanzania.

Also from Crystal Classics, this aesthetic aegirine from Mount Malosa, Zomba District in Malawi.

This big crystal of sturmanite from N'Chwaning Mines, Kuruman, Kalahari Mountain Fields, N. Cape Province, South Africa, was also seen at Crystal Classics'.

Something I have rarely seen before was spessartite from Tanzania (Sangulungulu, Loliondo) on matrix. Seen at Cristalli's booth.

We also saw several dealers carrying some gorgeous specimens of tourmaline from Russia (Malkhan, Krasnyi Chikoy, Siberia, Russia), displaying a perfect termination. Pregi Gemme's specimen

CC minerals (France) had some really good pyromorphite from Asprières, Aveyron, in France.


Going from the Mineral Show to the Gem show does not even take 10 min (walking). And, it's not a bad walk, look at that!
Unfortunately, couldn't bring back any "saucisson" nor foie gras...


The Gem show is still developing, with more and more good quality gems,  but also some great jewelry. Above there is a man working copper, making bracelets and other jewelry pieces.

Here, another person was showing the work of a gem cutter.

While most of the show happens underneath tents, they are few buildings hosting dealers, such as the Salle Prestige at the Gem Show.

 A few fun gems here: some unheated colorful tanzanite crystals (above and below)! They come in all colors, the pink and purple ones being the rarest. Seen at Valerio Zancanella's booth.

Adolfo De Basilio and Victor Tuzlukov showing off some incredible gems. Victor is a master cutter; he showed us some spectacular cut gems, with hundreds of facets. Including...
... this gorgeous faceted pearl.

As you know by now, there is no such thing as a show report without an opal! This one comes from Welo, Ethiopia, and contains some inclusions (manganese oxides?) arranged in a stunning pattern (picture above and below).

Talking about opals, we got a donation of rare French opals by Hadrien Begon. Thanks again Hadrien!


A spectacular party was thrown this year again by the organizers: all the dealers and guests were invited to a giant barbecue party, by a lovely summer night, in Sainte-Marie. I don't know how many people attended, but it looked like it was a thousand at least. Again, we had great people serving the food and the drinks, awesome atmosphere, and an entertaining band that made everybody dance throughout the night. What a memorable night!

A perfect evening for a giant barbecue!

Time for a drink. But where are the glasses?

Our table, serious talks going on.

Everything is better with food.

Gian Carlo, Alan and Jean-Marc. Happy curators!

A great selfie! Photo credit: Bryan Swoboda.
Gian Carlo, Ian and Cathie enjoying a well deserved drink!

Mr. le Maire, Claude Abel, welcoming everybody.

Did I mention the drinks yet?

A curator showing some talents. Bryan S., did you notice that he was playing with your camera?

"Diamonds are a girl's best friend". 

 Fun times!
And Bryan recording it!

Great days, fun nights. That's the spirit of Sainte-Marie! Just another picture below with a few friends, at the Auberge des Bagenelles (photo credit: Bryan Swoboda).

I will finish this post with pictures of those lovely evenings in Sainte-Marie. Again, thanks to the organizers for the invite. And... don't miss the first ever "What's Hot in Sainte-Marie" coming up by the end of the year!

Bryan Swoboda welcoming Claude Abel to the "What's Hot" family!

Bergi: mascot of the Sainte-Marie school of Aalberg. 


All photos by E. Gaillou for NHM, unless acknowledged otherwise.