The Aurora Diamond Collection

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Origin of name

The Aurora Diamond Collection is the most comprehensive collection of naturally colored diamonds in the world, consisting of all the multifarious colors in which diamonds exist in nature, represented in different shapes, sizes, color saturations, as well as modified colors. There are 296 diamonds in the collection weighing a total of 267.45 carats, put together over a period of almost 25 years by New York diamond collectors Alan Bronstein and Harry Rodman. The name Aurora selected for this diamond collection seem to have been inspired by the spectacular natural phenomenon occurring at high altitudes in the upper layers of the atmosphere over the earth's magnetic poles, known as Aurora Borealis (northern lights) and Aurora Australis (southern lights). The spectacular multicolored display of the Aurora is believed to be caused by charged particles from the solar wind being captured by the magnetic field of the earth and conducted towards the magnetic poles, where they collide with oxygen and nitrogen atoms in the atmosphere, knocking away some of their electrons, forming ions in excited states. The ions emit radiation in various wave lengths creating the characteristic colors of the Aurora, such as red, green and blue.

Characteristics of the diamonds

 Colors :- The Aurora collection of 296 diamonds consists of diamonds belonging to 12 different varieties of pure colors. These colors are blue, green, olive, yellow, brown, orange, red, pink, purple, black, gray and white. The collection also contains diamonds of modified colors which perhaps may include several of the following combinations :- grayish blue, purplish pink, orange pink, brownish pink, purplish red, brownish red, yellowish brown, orange brown, brownish yellow, brownish orange, pinkish purple, brownish purple, grayish purple, yellowish green, bluish green etc.

Average size :- Most of the diamonds in the collection are less than one carat in weight.

Shapes :- The shapes of the diamonds included all possible shapes in which diamonds are cut in the diamond industry today, such as round, oval, cushion, pear, marquise, heart, trillion, emerald, asscher, princess,  radiant etc.

Types of diamonds :- The diamonds in the collection belonged to all the different types and sub-types in the classification of diamonds.

The near-colorless (G-J), faint yellow (K-M), very light yellow (N-R), light yellow (S-Z), fancy light yellow and fancy yellow diamonds in the collection, are all Type Ia diamonds, in which the color is caused by nitrogen atoms found as aggregates of 2, 3, or 4 atoms, known as A-aggregates, N3 centers and B-aggregates respectively. A & B aggregates do not affect the color of diamonds, but N3 centers do. Almost 98 % of naturally occurring diamonds are Type Ia.

The darker shades of yellow such as fancy intense yellow, and fancy vivid yellow including the canary yellow, and the different shades of orange are Type Ib diamonds, caused by single nitrogen atoms scattered in the crystal. Only 0.1 % of naturally occurring diamonds are Type Ib.

Nitrogen atoms absorb visible light in the blue region of the spectrum, causing its complementary color yellow to appear. Very rarely nitrogen atoms absorb visible light in the green region of the spectrum causing its complementary color orange to appear.

The absolutely colorless diamonds (D-F), are Type IIa diamonds, in which the colorless nature results due to the absence of factors that cause color in diamonds, such as chemical impurities, and structural abnormalities. Their occurrence is 1-2 % of all naturally occurring diamonds.

Pink, red, purple, and brown colored diamonds are alsoType IIa diamonds in which the color is caused by the plastic deformation of the crystal structure. There occurrence however is less than 0.1 % of all natural diamonds. The occurrence of plastically distorted brown diamonds is very high in the Argyle diamond mines, and accounts for almost 80 % of the production of gem quality diamonds

Green diamonds are also Type IIa diamonds, in which the green color is caused by the exposure of diamonds over long periods of time to natural radiation like alpha, beta and gamma radiation, which alters the structure of the diamond, producing the green color. The occurrence of green diamonds is less than 0.1 % of all naturally occurring diamonds.

Blue diamonds are Type IIb diamonds, in which the presence of trace quantities of boron impurities in the crystal structure of the diamond imparts the blue color, as well as semi-conducting properties to the diamond. Their occurrence is less than 0.1 % of all naturally occurring diamonds.

Black diamonds are in a class by themselves and not classified with other diamonds. Black diamonds are not made up of large single crystals like conventional diamonds, but are aggregates of millions of tiny crystals. They are porous and contain trapped gases. They are harder than conventional diamonds, and are difficult to cut and polish. However there may be softer areas within the crystal, that results in large losses when attempting to cut a black diamond. The black color is caused by iron compounds like hematite and magnetite associated with the crystals. Another important fact about black diamonds is that they do not originate in lamproite and kimberlite pipes like the conventional diamonds. Scientists of the Florida International University has proposed an extra-terrestrial origin for black diamonds, found only in Brazil and the Central African Republic.


The Aurora Collection was initiated by Alan Bronstein in the 1980s. Soon after graduating from college, his mother who was the book-keeper for the Diamond Dealers Club of New York, suggested that he become a diamond broker as a means of livelihood until he made up his mind as to what he should really do in the future. He took up the challenge and eventually became a successful broker, during which period he was exposed to diamonds of all types and acquired sufficient knowledge about diamonds and the diamond industry. There was no turning back. Alan Bronstein had decided that he had made the right choice as far as his future career was concerned.

The inspiration that initiated the collection

Then came the life changing moment in his career, that provided the much needed stimulus to initiate the world renowned collection. This occasion is best described in Alan Bronstein's own words.

 "I will always remember that day in 1980 when a golden yellow diamond that burned like the evening sun setting in the western sky was flashed in front of my eyes by a fellow trader. It had a hypnotic glow that kept me staring in wonder. I did not know at the time that this experience had been for me a true epiphany, that the revelation of such beauty would instill in me a passion to learn everything possible about these mystical stones. I did not know then that the seed for the Aurora Collection had been firmly planted in my soul."

Putting together the diamond collection

Alan Bronstein started to acquire colored diamonds partly for business, but mainly to satisfy his passion to start a collection of  colored diamonds, because at that time there was hardly any demand for colored diamonds. At the beginning the focus of his collection was yellow, pink and blue diamonds with GIA color grading of fancy light, fancy, and fancy intense. These were also the most commonly traded colors, and the stones he purchased could also serve as comparison stones in his business. He purchased small stones of between 0.25 and 0.50 carats, as these were freely available and less costly.

As his collection expanded he started to go in for less popular varieties such as brown, orange, olive and gray as his intention was to have a comprehensive collection of colored stones. These colors are not pleasing to many but they have a beauty of their own. Eventually he was able to put together the first 25 stones of  his collection, and Alan Bronstein says that it was amazing to see how they blended and contrasted with each other. In studying his collection and comparing with sample stones he noticed subtle differences in certain colors that was not perceptible without comparison. For example by placing a pure pink sample stone closer to different pink diamonds he was able to identify color modifiers such as purple, orange, brown and grey in pink diamonds. These observations made him realize the infinite color combinations possible in diamonds, and increased his enthusiasm in bringing together as many pieces of the diamond puzzle as possible, and sharing this unique experience with the public.

Harry Rodman joins Alan Bronstein

The greatest boost to Alan Bronstein's single-handed effort in putting together a comprehensive colored diamond collection came in 1986, when Harry Rodman, a family friend and mentor, and a D-day veteran who had just sold his 50-year old gold refining business, intrigued by Alan Bronstein's idea of putting together a unique collection, joined him. Together they pursued their common goal in expanding the collection, so that it becomes a truly representative collection. They moved from place to place following up information received on the availability of a particular color of diamond. Sometimes their search proved futile as the stones they saw did not match the description provided. A red diamond for instance actually turned out to be an orange brown. Likewise a green diamond was actually an olive-gray, and a purple diamond turned out to be pinkish-brown.

Accidental purchase of a chameleon diamond

In their quest for colored diamonds their greatest surprise came when they purchased a 2.50-carat pear-shaped dark olive green diamond that was brought back by a friend when he visited Israel, after it was certified by the GIA as a natural colored diamond. Having purchased the diamond Alan Bronstein put the diamond in his vault and went about his normal activities. After about a week later he happened to open the vault again, and to his utter surprise he discovered that the olive green diamond he purchased about a week ago, was no longer olive green but had an intense yellow color. Alan Bronstein wondered how the stone could have been switched when no one could have had access to the vault. Suddenly, right in front of his eyes the intense yellow diamond changed back to its original olive green color, to his great relief. Immediately it became apparent to Alan Bronstein that what he was holding in his hand was indeed a rare Chameleon diamond, highly prized by collectors. He was happy that he was able to acquire this rare diamond for his collection.

Invitation to the Argyle Pink Diamond Tender

Alan Bronstein and Harry Rodman had made several trips together to Antwerp looking for colored stones and made several purchases. They also attended the Argyle Pink Diamond Tender held annually in Geneva. On four out of ten occasions the tender was held, the whole lot of stones on offer was purchased by a single person who made a universal bid on all the stones. Alan and Harry were successful in purchasing different varieties of pink stones at these auctions, but the most important of these purchases was a 0.53-carat octagonal shaped, intense purplish-pink diamond, which almost appeared like a red diamond.

According to Alan Bronstein the purer shades of pink, blue, yellow and orange may be considered the elite among colored diamonds, but he says that this does not eliminate the beauty and rarity of modified colors.

Display of the Aurora Collection

As the collection continued to expand Alan and Harry started to arrange the stones in different patterns, creating more and more complex pictures of flowers, insects, animals and abstract designs. Harry Rodman, who was an artist thought that this was art in a new medium. Alan and Harry later agreed to lend their collection to the American Museum of Natural History, where it was put on public display in the Morgan Hall of Gems from 1989 to 2005. In arranging the collection for display at the museum Alan and Harry decided that the best arrangement possible to reveal the full color of the diamonds to the public would be the pyramid shape. In 1998, the Aurora Collection was the centerpiece of "the Nature of Diamonds" exhibition, organized by the American Museum of Natural History that toured the United States, Canada and Japan. In the year 2005, the Aurora collection was invited to participate in the "Diamonds" exhibition, organized by the Natural History Museum of London, which is said to have a visitor turnout of 3.6 million each year. "Gems like these were not meant to be imprisoned in a dark underground safe for the momentary pleasure of a few eyes. The true value of a collection is sharing it with as many people who are interested in experiencing natures diversity of expression." says Alan Bronstein. This is the line of thinking of the two greatest collectors of colored diamonds in human history, when they agreed to the display of the collection at exhibitions around the world, the same trend of thoughts that initiated the  unique collection in the first place.

Quotes from Alan Bronstein and Harry Rodman

The following quotes from the collectors of the diamond Alan Bronstein and Harry Rodman, would serve as an ideal summing up for our account on this unique collection, which has become an unprecedented contribution to the common human heritage.

"For my partner Harry Rodman and I, this collection represents the diversity of nature and how these differences when brought together, enhance and complement each other's unique traits. We also think of the Aurora Collection as art in a new medium - perhaps as a painting made of little drops of high-energy colored lights growing from the canvas, arranged in the shape of a pyramid, symbolizing a vortex of energy. The astonishing array of colors in this pyramid-like form creates a hypnotic allure that can entrance the viewer with compelling and irresistible delight." - Alan Bronstein.

"I am inspired by the varieties of colors, which remind me so much of the phenomenon of the Aurora Borealis, which suddenly light up the northern sky and are rarely seen by most people, and somehow I wanted to hold on to that feeling." - Harry Rodman.

The Butterfly of Peace Collection

Alan Bronstein and Harry Rodman are also credited with the creation of another collection known as the "Aurora Butterfly of Peace", in which 240 loose natural-color diamonds, weighing 166.94 carats, consisting of a variety of colors, sizes, and cutting styles, are arranged in the design of a butterfly, creating an outstanding work of abstract art. The "Butterfly of Peace Collection" was also displayed at several exhibitions, such as the one organized at the Smithsonian National Museum of Natural History in Washington DC. A unique feature of this exhibition  was the special lighting of the exhibit that alternated between natural and ultra-violet, that caused the diamonds to glow each time they were exposed to the U-V lights.

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Dr Shihaan Larif
Founder Internet Stones.COM



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