Friday, October 23, 2009
The Royal Purple Heart Diamond
This is a diamond I am still in the process of researching. The article I found with the stone reads "The Royal Purple Heart Diamond is the largest fancy vivid purple diamond known to exist, weighing 7.34 carats. This unique stone has been expertly cut and polished into a perfect heart shape to allow the striking natural purple color to dazzle to maximum effect. Natural purple diamonds are among the rarest and most highly sought after color in which diamonds occur. Large pure purple diamonds (i.e. stones over 5 carats) are especially prized. The Royal Purple Heart Diamond was cut by and is a joint venture with the Julius Klein Diamond Corporation." The gem has a clarity of I1.
The Queen of Holland Diamond
There are differing opinions concerning the origin of this 135.92-carats cushion-cut diamond. The Dutch firm F. Friedman & Co. cut it into its present shape in 1904. They owned it for several years, exhibiting it at the 1925 Paris Exhibition of Arts and Industry. The Dutch sovereign from whom the stone takes its name was Queen Wilhelmina, who reigned from 1890 to 1948.
This suggests the possibility that the Queen of Holland was mined in South Africa, but nothing is known of the diamond's earlier history until it arrived in Amsterdam at a time when numerous South African diamonds were finding their way there. Yet there are experts who think that the Queen of Holland is a typical Golconda stone.
The Maharajah of Nawanagar purchased the Queen of Holland and Cartier set it as the centerpiece of the pendant to the magnificent ceremonial necklace of the Prince. Jacques Cartier, who assembled the necklace, referred to it as "a really superb realization of a connoisseur's dream."
Cartier eventually bought the diamond from the Maharajah's family and sent it to their London branch in 1960. 30 years later, it was sold for a reported $7,000,000. The Queen of Holland is now owned by Robert Mouawad.
The Porter Rhodes Diamond
Considered to be the finest American diamond found up to that time (1880), the 153.50-carat rough this stone was cut from came from the claim of Mr. Porter-Rhodes in the Kimberly Mine. It was valued at $200,000. In 1881, Mr. Porter Rhodes visited the Osborne House in London and showed it to Queen Victoria, who exclaimed over its great purity and beauty. Empress Eugenie, who also saw the great diamond at the same time, remarked that it was "simply perfection," not knowing what to compare it with. At that time, it was the general belief that South Africa diamonds were inferior. Victoria asked, "Is it really from Cape?" Eugenie remarked, "Are you sure the diamond is from South Africa, and have you not had it polished a little? I have always been under the impression that diamonds from the Cape were very yellow and worth but little."
The Pink Sun Rise Diamond
Famed diamond cutter Gabi Tolkowsky pays homage to his 273.85-carat Centenary with the Pink Sun Rise, a 29.78-carat diamond with a design similar to the Centenary's. The diamond is a rare, flawless pink and was cut by Tolkowsky and his team of master craftsmen. Tolkowsky is also famed for cutting the largest diamond in the world, the Golden Jubilee
The Peacock Diamond
With the purchase of this unusual, 20.65-carat Fancy Intense Yellow, IF clarity (internally flawless) diamond by C.D.Peacock, Chicago's premier jewelry store plans to try to change the way people in America think about fancy colored diamonds -- many people still don't even know there is such a thing as a fancy colored diamond.
According to Ray Perlman, a consultant to C.D. Peacock and former Chairman of the Board of the New York Diamond Dealers Club, most people have no idea that diamonds occur in a color other than colorless (white). Yet, notes Perlman, when asked to identify the world's most famous diamonds, most people will name the Hope Diamond which is Fancy Dark grayish-blue, and the Tiffany Yellow which is golden yellow. It is also true that some fancy colored diamonds have been valued higher than colorless diamonds of the same size. Take for instance the 0.95-carat fancy red round brilliant that set the world record, price-per-carat for diamonds. It went for $880,000 at Christies NYC. That comes to about $926,000 per carat. But then again, red and purple diamonds are the two rarest colors. The stone is now called the Hancock Red.
The Paragon Diamond
of 1999. With a hand in the photo for scale,
it gives you a good idea how large the stone is.
This very unusual 7-sided diamond is known as the Paragon, and weighs 137.82 carats. The Graff Diamond Co. of London cut the gem, and is its current owner. The necklace has a diamond carat weight of 190.27 carats, and separates to both necklace and bracelet lengths. The piece features Fancy Intense blue, yellow and pink diamonds along with the Paragon Diamond, a 137.82-carat D-color Flawless diamond, evolved unmistakably into Graff's creation for the Millennium.
The Ashberg Diamond
It is said that this amber-colored, cushion-shaped diamond weighing 102.48 carats, was formerly part of the Russian Crown Jewels. It must have been a late addition to that collection because the stone bears all the characteristics of one from South Africa. In 1934 the Russian Trade Delegation sold the diamond to Mr. Ashberg, a leading Stockholm banker. The Stockholm firm of Bolin, former Crown Jewellers to the Court of St. Petersburg, mounted it as a pendant. In 1949 the Ashberg was displayed, mounted in a necklace containing diamonds and other gemstones, at the Amsterdam Exhibition, the aim of which was to attract new workers to the diamond industry.
Ten years later the Bukowski auction house in Stockholm put the Ashberg up for sale but it failed to reach its reserve and was withdraw. Then its owner succeeded in selling the gem to a private buyer whose name was not revealed. Finally, in May, 1981, Christies auctioned the diamond in Geneva where once again it failed to reach its reserve and was withdrawn.
Thursday, October 22, 2009
The ArcotsDiamond
The Hanoverian rulers of Great Britain amassed a large collection of personal jewelry and Queen Charlotte, the consort of King George III, was surely no excpetion. She received many jewels, the most notable being the diamonds she was given by the Nawab of Arcot. These included five brilliants, the larest of which was a 38.6-carat oval-shaped stone and was later set in a necklace with the two smallest stones.
Arcot, a town near Madras, became famous for its capture and defense by Clive in 1751 during the war between the rival claimants to the throne of the Carnatic. In 1801 it passed into British hands following the resignation of the government of Nawab Azim-Ud-Daula, who had given the diamonds to Queen Charlotte in 1777.
The Archduke Joseph Diamond
This 76.45-carat diamond gets its name from from Archduke Joseph August (1872-1962), a previous owner of the gem and a prince of the Hungarian line of the Hapsburg dynasty. The Archduke was a descendant of the Emperor Leopold II, son of Empress Maria Theresa who owned the famous Florentine Diamond, one of the most notable and unique diamonds in history and an heirloom of the Hapsburgs for many years. But whereas the Florentine was unusually large for an Indian diamond and light yellow in color, the Archduke Joseph is a colorless diamond; it possesses the most notable characteristic of the best Golconda diamonds, namely a high internal clarity. Thus its D-color certification. It is cut in a rectangular cushion shape, perhaps a style of cutting that is not entirely unfitting with its Indian origin.
Sunday, September 27, 2009
Ballerina Setting
One of the classic multi-stone ring designs, the ballerina, derives its beauty from the placement of tapered baguettes which flow around a center stone to form a 'tutu', that short flared skirt worn by ballet dancers. There are ballerina rings in which baguettes are set in an undulating curve that literally emulates the tutu skirt of a dancer.
Flush Setting
The flush setting is one of the subtlest diamond-setting techniques. Stones are sunk into the mounting until they are nearly level or flush with the surface. Only the table of the stone and a bit of the upper pavilion facets show.
This technique seems to go against everything we know about diamonds in relation to light, but it's become quite a popular setting. It's a very subtle look, and one that appeals to the woman who likes the idea of tiny, glittering bits of light twinkling like stars in the sky.
The flush setting is also used for larger stones, offering great protection and a modern look.
Cluster Setting
The cluster setting is another variation on the theme of choosing a ring with a number of smaller diamonds. There are cluster rings with the stones arranged in the form of a stylized flower, or those done as an abstract arrangement of stones.
Cluster rings are usually multi-level, with considerable height above the hand. The arrangement of stones can be quite open and airy looking, or it may be more tightly arranged. The choice is a matter of taste, but the shape of the finger can also play a role in making that choice.
Remember that the openwork design lengthens the look of the finger and the hand, while the more closed design draws the eye toward the hand.
Bead Setting
These beads, larger and more prominent, may be engraved or decorated. The diamonds may also be slightly larger in size. By varying the size of the stones and the size of the beadwork, the designer creates a totally different look.
Consider the impact you want your ring to make. Are you looking for the dazzling glitter of tightly set Pavé -- or the more decorative look of bead-set, larger diamonds? Both are beautiful, and the choice is yours.
Pavé Setting
When the surface of a ring appears to be covered with tiny diamonds, the technique is called Pavé which means paved. It's an apt name because the surface looks a bit like a very pretty street paved with cobblestones.
Tiny diamonds are placed in small holes that have been drilled out of the ring shank. On a band that does not taper across the top, each diamond should be exactly the same size. The diamonds are placed in rows, but in such a way that they fill as much of the space of the surface as is possible without actual touching. The more precisely cut the diamonds, the better the final appearance of the ring.
Each tiny diamond, weighing just a few points, is fully cut with 58 facets. Though small in size, each stone contributes to the overall, shimmering look of the design. After it is positioned in its hole, tiny bits of metal from the surface of the shank are pushed over the edge of the diamond, forming tiny beads to hold the stone in place.
Pavé is a demanding technique that is most successfully accomplished in the hands of a patient and extremely talented jeweller.
The cost of a Pavé-set diamond ring is in the hand setting of the diamonds; as such, it is often much more a determinant of price than the cost of the diamonds and the gold. To evaluate a ring that is Pavé set, look at the overall design. Are the diamonds laid out in such a way that the entire surface of the ring looks like a glittering carpet of gems? That's the sign of a well-designed and well-made ring.
If a section of the ring is Pavé-set, with certain areas tapering to a point, the diamonds should diminish in size as the Pavé area narrows. This requires the most precise selection of diamonds.
All of these elements add to the time needed to make a ring, and -- as the saying goes -- time is money. The value of a Pavé-set ring is not as obvious as one set with a major solitaire; but when you appreciate the work needed to produce one, you'll also appreciate a fair price when you see it.
Channel Setting
Channel setting is also used to set round diamonds. Channel setting offers a sleek, elegant appearance, though the end result is a very different look.
Setting round diamonds into channels leaves small spaces closest to the metal bars of the channel. By choosing round diamonds, the designer creates a clean line of stones, yet one with greater brilliance than is possible with baguettes. This also offers a less restrained look, and may be more suitable when a ring has a round center stone.
Channel setting is also used when there is no center stone at all. The placement of baguettes around an entire band is a beautiful choice for a wedding band, one that goes well with a matching ring set with a diamond solitaire.
Channel setting protects the diamonds extremely well. None of the edges are exposed, and so they are not subject to hard knocks or general wear and tear.
A variation of the channel set is called the bar channel. Here, the metal plates rise to top level of the stone, and so are visible between the stones. This gives a slightly different visual effect, and can be very striking if the contrast between the metal and the stone is significant.
Bezel Setting
A bezel setting is a collar of precious metal that wraps around the diamond.
The bezel is attached to the top of the ring and stands up above it, adding height and another dimension to the setting. Although solid bezels have a very traditional look, the bezel may be 'split' into two sections, arcing around just part of the diamond. This is called a half bezel.
This simple change suddenly opens up the setting and gives it a totally modern look. The technique may also be used on a fancy cut diamond -- with an arc of precious metal around the wide curve of a pear shape and another, V-shaped section of precious metal embracing the narrow end.
Diamond Ring Settings
Whether you're choosing a diamond solitaire, a ring with a number of stones, or an open-work lattice ring in which the diamonds flow along the lines of the setting, the way the stones are held in the setting is an integral part of its design.
Each setting technique creates a look that is part of the overall style of the ring. You may like one ring rather than another simply because of the setting technique used.
Prong Settings:
A prong setting is the one most often used to hold a solitaire. A prong setting puts the emphasis on the diamond and not the metal supporting it. The purpose of any setting is to hold the diamonds securely in the mounting and at the same time allow light to enter the diamonds for maximum brilliance.This is obviously a delicate balancing act. The more metal used to hold the diamonds, the more secure they are; the less metal used, the greater the chance for the diamond to reflect light.
Very thin wires of gold or platinum (the prongs) are used to hold the diamond securely in place. The diamond may be raised high up above the shank, to give it a larger, more important appearance, with only a suggestion of metal showing.
In such a setting, the prongs are attached to the central setting of a ring, known as the head or basket. Each prong extends upward and outward from the head, arching over the diamond to form a secure grip.
The ideal prong tapers to a rounded point. The prongs should be placed at the key points of the diamond, typically at four corners or at four, five or six points evenly spaced around the stone -- this diamond setting offers security without interfering with the stone's brilliance.
The prong setting can also be found in a few variations. One such variation, called the V-prong setting, functions on the same basic concept, but it uses prongs which, when viewed from above, appear to be curved into a V-shape. The right angle of the wire is cut to allow the corner of the gem to rest and be held by the wire.
V-prongs are generally used for diamond shapes with points -- such as the corners of the square Princess Cut or the tip of the pear shaped diamond. The v-prong provides additional protection to the points which are often thin, fragile, and subject to chipping if left exposed.
Another variation on the prong setting is called the common prong. Here, the metal wire is grooved at the top, and is used to hold two gemstones by their side (girdle). This technique is used to give a close side-by-side gemstone relationship without the metallic interference of too many prongs.
Sunday, August 23, 2009
Amsterdam Diamond
This rare black diamond of African origin is reported to be completely black. It weighs 33.74 carats, has 145 facets and was cut from a 55.85-carat rough. The stone was first shown in February, 1973, at D. Drukker & Zn., Amsterdam. It was auctioned off at www.christies.com in November, 2001, for $352,000, setting a world record for the highest price fetched by black diamond at auction. The stone is cut in a pear shape, with horizontally split main facets on the crown.
Allnatt Diamond
When Porter Rhodes traveled to the Isle of Wight in 1881 to show to his fine white diamond crystal to Queen Victoria and Empress Eugenie of France, who was at that time residing nearby, he helped to dispel a myth: South African diamonds were usually yellowish in color and therefore less valuable. Both the Queen but in particular the Empress, who was knowledgeable about diamonds, believed this to be true and were, therefore, surprised to examine a fine white octahedral crystal originating from the Cape Mines of South Africa. It was not until the Excelsior was found in 1893, the Jubilee in 1895 and above all, the discovery of the Premier Mine in 1902 that South Africa finally achieved recognition as a source of large white diamonds as well as yellow ones.
The early years of the South African diamond mining industry certainly witnessed the appearance, in unheard of numbers, of large yellow crystals, many of them octahedral in shape. The reigning Shah of Persia, Nasir ud-Din Shah (1848-1860) was among the first to appreciate them because he added numerous yellow diamonds to the Crown Jewels of Iran, the largest of which is a 135-carat monster rivaling the Regent Diamond in size and shape. A few, including the Tiffany Yellow, came from the Kimberly Mine but by far the greatest number originated in the De Beers Mine, which is the most likely source the Allnatt originated from.
This 102.29-carat cushion cut, its color having been certified by the GIA as Fancy Vivid Yellow, VS2 clarity, is named after its former owner, Alfred Ernest Allnatt. He was a soldier, a sportsman, an active patron of the arts and a noted benefactor in many spheres. He paid a then world record price for The Adoration of the Magi by Rubens which he presented to King's College, Cambridge, England, as an alterpiece for its famous chapel. He also had a passion for the Turf and bought 11 yearlings formerly owned by the late Sir Sultan Mohammed Aga Khan; he commented at the time, "All I know about horses is they are nice things to amble about on." The Aga Khan also owned several exceptional diamonds, among them the 33.13-carat pear-shaped Aga Khan III, which came up for sale at Christie's in Geneva in May of 1988.
Major Allnatt did not buy any of the Aga Khan's diamonds to add to his yearlings, but he did purchase this very fine diamond and in the early-1950s he commissioned Cartier to design a floral brooch setting for it. The piece is a design of a flower with five petals, lined with white baguette-cut diamonds, the petals themselves being comprised of brilliant cut diamonds, and the stem and two leaves also being comprised of the same cutting styles. The Allnatt is at the center of the flower. The entire piece is made of platinum. It was auctioned by Christies, again in Geneva, in May of 1996. On that occasion it fetched the phenomenal sum of $3,043,496. The present owner of the gem is the SIBA Corporation.
Hope Diamond
The Hope Diamond is a large, 45.52 carats (9.10 g),deep-blue diamond, housed in the Smithsonian Natural History Museum in Washington, D.C. The Hope Diamond is blue to the naked eye because of trace amounts of boron within its crystal structure, but it exhibits red phosphorescence under ultraviolet light. It is classified as a Type IIb diamond, and is famous for supposedly being cursed.
An examination in December 1988 by the Gemological Institute of America's Gem Trade Lab (GIA-GTL) showed the diamond to weigh 45.52 carats (9.104 g) and described it as "fancy dark grayish-blue." A re-examination in 1996 slightly rephrased that description as "fancy deep grayish-blue."The stone exhibits an unusually intense and strongly-colored type of luminescence: after exposure to long-wave ultraviolet light, the diamond produces a brilliant red phosphorescence ('glow-in-the-dark' effect) that persists for some time after the light source has been switched off. The clarity was determined to be VS1, with whitish graining present. The cut was described as being "cushion antique brilliant with a faceted girdle and extra facets on the pavilion." The dimensions in terms of length, width, and depth are 25.60mm × 21.78mm × 12.00mm (1in × 7/8in × 15/32in).
Saturday, August 15, 2009
Gabi Tolkowsky
Gabriel S. "Gabi" Tolkowsky is one of the world's most renowned diamond cutters, the sixth generation of the Tolkowsky family to make his name in the trade. He is the great nephew of Marcel Tolkowsky, the father of the modern round brilliant diamond cut.
He was trained by Marcel and his father Jean, beginning in 1956 before becoming Managing Director and Chairman of Diatrada, N.V., a division of De Beers in the 1970s He invented the "flower cuts" in 1985–86, and since 1995, he has been a worldwide consultant to the De Beers group. In 1988, he was commissioned by them to act as master cutter for the 273.85 carats (54.77 g) Centenary Diamond, the largest and most flawless modern cut diamond in the world, a task which took three years.The gem was kerfed (hand-cut) in order to avoid heat- or vibration-related damage from saws or lasers.
He was a major interviewee in The Play of Light, a 2000 documentary film about the creation of a diamond from a rough stone, and in 2003 he was knighted by the Belgian government with the title of Chevalier de L'Ordre du Roi Leopold II, for his services to the diamond industry.
Cutting the Centenary Diamond
Cutting such an immense and valuable diamond required expertise and a considerable investment. Gabi Tolkowsky was chosen to head the team responsible for cutting the Centenary Diamond, along with Geoff Woolett, Jim Nash and Dawie du Plessis, assisted by a specially picked group of engineers, electricians and security guards to facilitate in the work on Centenary Diamond. There was a special room designed underground in the De Beers Diamond Research Laboratory in Johannesburg, South Africa for the sole purpose of working on the Centenary Diamond with design specifications including strength and stability so as to preclude mechanical vibration and temperature variation to minimize any mitigating factor that might interfere with the cutting of the Centenary Diamond.
The initial efforts were done by hand rather than with a laser or saw so as not to heat or vibrate the diamond. After cutting and removing 50 carats (10 g) of cracked material over 154 days, the team was left with an egg-shaped gem of approximately 500 carats (100 g). Thirteen different designs were presented to the De Beers board, with a strong recommendation for what became the eventual modified heart-shaped design. The shape was described as, "Effectively, the Centenary Diamond is shaped like a heart-shape, but it does not have a groove. The image the team had in mind was a shape which would adorn the turban of a Sultan or a Maharaja."
The Centenary Diamond
The De Beers Centenary Diamond is, at 273.85 carats (54.77 g), the third-largest diamond to have been produced in the Premier Mine. The Centenary Diamond is rated in color as grade D color by the Gemological Institute of America, which is the highest grade of colorless diamond and is internally and externally flawless. It was named the Centenary Diamond as it was presented in the rough for the Centennial Celebration of De Beers Consolidated Mines on May 11, 1988. The Centenary Diamond was unveiled in final form in May 1991.
Discovery
The Centenary Diamond was discovered in the Premier Mine on July 17, 1986 using their X-ray imaging system. The original rough was 599 carats (120 g) and it was presented on May 11, 1988 in the Centennial Celebration of the De Beers Consolidated Mines. As then-chairman Julian Oglivie Thompson said, "We have recovered at the Premier Mine a diamond of 599 carats (120 g) which is perfect in color – indeed it is one of the largest top-color diamonds ever found. Naturally it will be called the Centenary Diamond."
The Steinmetz Pink
The Steinmetz Pink is a diamond weighing 59.60 carats (11.92 g), rated in color as Fancy Vivid Pink by the Gemological Institute of America. The Steinmetz Pink is the largest known diamond having been rated Vivid Pink. As a result of this exceptional rarity, the Steinmetz Group took a cautious 20 months to cut the Pink. It was unveiled in Monaco on May 29, 2003, in a public ceremony.
The Steinmetz Pink was displayed as part of the Smithsonian's "The Splendor of Diamonds" exhibit, alongside the De Beers Millennium Star, the world’s second largest (the Centenary Diamond is the largest) top colour (D) internally and externally flawless pear-shaped diamond at 203.04 carat (40.608 g), the Heart of Eternity Diamond, a 27.64 carat (5.582 g) heart-cut blue diamond and the Moussaieff Red Diamond, the world's largest known Fancy Red diamond at 5.11 carats (1.102 g).
The Heart of Eternity
The Heart of Eternity is a diamond measuring 27.64 carats (5.528 g), rated in color as "Fancy Vivid Blue" by the Gemological Institute of America. The Heart of Eternity was cut by the Steinmetz Group, who owned the diamond before selling it to the De Beers Group.
The Heart of Eternity is a member of an exceedingly rare class of colored diamonds. It was found in the Premier Diamond Mine of South Africa. Blue (Type IIb) diamonds account for less than 0.1% of the output of the Premier mine, which is the only mine in the world with an appreciable production of blue diamonds. Of the ten colored diamonds that drew the highest bids, six of those ten were blue diamonds, rating values as high as $550,000 to $580,000 per carat ($2750–2900/mg).
The Heart of Eternity was unveiled in January 2000 as part of the De Beers Millennium Jewels collection, which included the Millennium Star. The Heart of Eternity was featured with ten other blue diamonds; the collection of blue diamonds totaled 118 carats (23.6 g). The De Beers Millennium Jewels were displayed at London’s Millennium Dome throughout 2000. An attempt on November 7, 2000 to steal the collection was foiled
During its exhibition at the Smithsonian, the Heart of Eternity was noted to be on loan from a private collector, giving rise to speculation that it was sold sometime during the exhibition at the Millennium Dome in London.
The Ocean Dream
The Ocean Dream is a diamond measuring 5.51 carats (1.102 g), rated in color as Fancy Deep Blue-Green by the Gemological Institute of America. The Ocean Dream is the only natural diamond known to the GIA to possess a blue-green hue, making it one of the rarest diamonds in the world. (A blue-green colour is commonly seen in artificially enhanced diamonds, whose colour is imparted by various irradiation methods.) After careful study, the GIA concluded that its distinct hue is a result of millions of years of exposure to natural radiation. The Ocean Dream originated in Central Africa, and is currently owned by the Cora Diamond Corporation.
The Ocean Dream was displayed as part of the Smithsonian's "The Splendor of Diamonds" exhibit, alongside the De Beers Millennium Star, The Heart of Eternity and the Moussaieff Red.
Friday, August 14, 2009
The Great Mogul Diamond
The Great Mogul Diamond, fabled 280-carat mogul-cut diamond, now lost, although presumed by historians to have been recut as the Orlov.
The Great Chrysanthemum Diamond
The Great Chrysanthemum Diamond is a diamond measuring 104.15 carats (20.830 g) with a Pear-Shaped Modified Brilliant Cut, rated in colour as Fancy Orange-Brown and I1 clarity by the Gemological Institute of America. The diamond's origins are in South Africa, where it was bought by the jeweler Julius Cohen as a 198.28 carat (39.656 g) rough in 1963. After buying it, Cohen returned to New York where he had it cut into its distinctive pear shape by S&M Kaufman. Because of its colouring similarities to the brown chrysanthemum, it was named after that flower.
The Great Chrysanthemum has been shown in a number of diamond exhibits throughout the United States. In 1965, the Chrysanthemum was named a winner of one of the Diamonds International Awards and was placed on display in the Rand Easter Festival in Johannesburg, South Africa. Julius Cohen later sold the diamond to an unknown and reputedly foreign buyer; it was later purchased by Garrards of London around 2003.
The Taylor-Burton Diamond
The Taylor-Burton is a diamond made famous when purchased by actor Richard Burton for his wife Elizabeth Taylor to celebrate her 40th birthday in 1972, receiving worldwide publicity for its size and value.
The original rough diamond was found in 1966 in the Premier Mine in South Africa, weighing 241 carats (48 g). It was cut by Harry Winston to 69.42 carats (13.88 g) in the shape of a pear.
The diamond was originally owned by Harriet Annenberg Ames and was subsequently purchased at auction by by Robert Kenmore, owner of the luxury brand Cartier. for a then record $1,050,000. It is regarded as the world's first million-dollar diamond - although other stones may have previously changed hands privately for seven figures or more, this was the first one to do so at a public auction. The Cartier company placed the diamond into a diamond necklace.
Richard Burton purchased the diamond for his wife, Elizabeth Taylor, who wore it publicly for the first time at Princess Grace of Monaco's 40th birthday celebration.
After their divorce, Taylor auctioned the diamond in 1978 for $5,000,000, which was used to build a hospital in Botswana.[3][2] It was bought by Henry Lambert, a New York-based jeweler.
Its current owner is Robert Mouawad, who had the diamond recut to 68 carats (14 g)
The Moussaieff Red Diamond
The Moussaieff Red Diamond is a diamond measuring 5.11 carats (1.022 g) with a triangular brilliant cut (sometimes called a trillion or a trilliant cut), rated in color as Fancy Red by the Gemological Institute of America. While this may seem relatively small when compared to other famous diamonds, the Moussaieff Red is, in fact, the largest Fancy Red the GIA reports having rated.
The Moussaieff Red is reported to have been found by a Brazilian farmer in the Abaetezinho river in 1990, in a region known as Alto Paranaiba which has a reputation as a source of large and fancy-coloured diamonds. In the rough, it is believed to have weighed 13.9 carats (2.78 g). The diamond was purchased and cut by the William Goldberg Diamond Corp., where it went by its original name the Red Shield. It is currently owned by Moussaieff Jewellers Ltd.
The Moussaieff Red was displayed as part of the Smithsonian's "The Splendor of Diamonds" exhibit, alongside The De Beers Millennium Star and The Heart of Eternity.
The Nizam Diamond
Nizam Diamond is believed to have been the most famous diamond in its time. There are tales about its size, around 340 carats (68 g). The story goes back to the rulers of Golconda, and is believed to found at Kollur Mine[1]. The precious stone gets its name from the Prince Nizam of Hyderabad.
The diamond was almond in shape.
The Millenium Star
The Millennium Star is a famous diamond owned by De Beers. At 203.04 carats (40.608 g), the world's second largest known top-color (D), internally and externally flawless, pear-shaped diamond.
The diamond was discovered in the Mbuji-Mayi district of Zaire (Democratic Republic of the Congo) in 1990 in alluvial deposits; uncut, it was 777 carats (155.4 g). It was purchased by De Beers during the height of the country's Civil War that took place in the early to mid-nineties. It took over three years for workers of the Steinmetz Diamond Group to produce the classic pear form. The actual cutting was done using lasers.
It was first displayed in October 1999 as the centerpiece of the De Beers Millennium diamond collection. The collection also includes eleven blue diamonds totaling 118 carats (23.6 g) and The Heart of Eternity. They were displayed at London’s Millennium Dome over 2000. There was an attempt on November 7, 2000 to steal the collection (see Millennium Dome raid), but the Metropolitan Police discovered the plot and arrested the robbers before their escape.Crime journalist Kris Hollington wrote a book called Diamond Geezers (ISBN 1843171228) about the attempted theft. The book also features a detailed history of the Millennium Star
How to Avoid Buying a Fake Diamond Ring:
- Ask if the stone is a genuine diamond or if it is a cubic zirconia, moissanite or other synthetic substance. A reputable jeweler will give you an honest answer.
Ask if the stone is a genuine diamond or if it is a cubic zirconia, moissanite or other synthetic substance. A reputable jeweler will give you an honest answer.
Check the wear and tear on the stone. A cubic zirconia is not as durable as a diamond and may show signs of scratches or nicks.
Take the stone to a trusted jeweler. Looking through a jeweler's loupe, he or she should be able to spot a fake stone right away. If the jeweler cannot tell by examining the stone, he or she will have instruments that can verify its authenticity.
It is highly recommended that you obtain a certificate from the Gemological Institute of America (GIA). The GIA, the largest impartial diamond grading authority in the world, issues a grading report after it examines the diamond and details it specifications.
Have the stone appraised by an independent appraiser who is affiliated with a professional organization such as the American Society of Appraisers (ASA). Ask for a certificate indicating the value and characteristics of the stone.
Herbert Tillander's drawing of the Koh-I-Noor's facet pattern
Herbert Tillander's drawingcut is of the Koh-I-Noor's facet pattern. This is
called a 'stellar brilliant' because of the extra facets on the stone's pavilion.
The Koh - I - Noor Diamond
"Reguarding its traditional history, which extends 5000 years further back, nothing need be said here; though it has afforded sundry imaginative writers with a subject for highly characteristic paragraphs we have no record of its having been at any time a cut stone."
The earliest authentic reference to a diamond which may have been the Koh-I-Noor is found in the Baburnama, the memoirs of Babur, the first Mogul ruler of India. Born in 1483, Babur (meaning 'lion' -- the name was not given to him at birth but appears to be a nickname, deriving from an Arabic or Persian word meaning 'lion' or 'tiger') was descended in the fifth generation from Tamerlane on the male side and in th fifteenth degree from Genghis Khan on the female side. With the blood in his veins of two of the greatest conquerors Asia has ever seen, it is not all that surprising that Babur himself should have become a great conqueror in his own right.
Wednesday, August 12, 2009
Heat-treated brown diamonds
The observation that brown color might related to the lattice imperfections has led to a technique to convert brown diamonds into more valued light-yellow or even colorless ones: the diamond is subjected to high pressures of 6-10 GPa and temperatures above 1600 °C that heals (anneals) those defects.The technique has been demonstrated in several research laboratories in Russia and US. In March 1999, Pegasus Overseas Ltd (POL) from Antwerp, Belgium, a subsidiary of Lazare Kaplan International, has started marketing of such diamonds which were processed by the General Electric (GE). Those diamonds have therefore received a name GE POL (or GEPOL) and were marketed in the US as Bellataire diamonds. The fact and the identity of the treatment process was considered so important that micrometer-sized letters "GEPOL" were inscribed with a laser on the girdles of every treated diamond.In 2004, however, the GE diamond section has been purchased by Littlejohn & Co. and renamed into Diamond innovations. Since 1999, several companies around the world have adopted the technique and use various brand names for the processed diamonds.
Natural brown diamonds
Whereas the brown color due to irradiation or nickel impurity can be easily recognized through spectroscopic (e.g. absorption) measurements, the majority of natural brown diamonds do not show any characteristic absorption peaks. Whereas the consensus has been reached that the color relates to the plastic deformation, the particular reason has not been reliably identified yet. Extended lattice defects such as dislocations and slip planes were the most popular candidate, however, recent results favor large clusters of vacancies (mini-voids) as a more likely cause.
Causes of color
Irradiation:
Irradiation of diamond by high-energy particles (electrons, ions, neutrons or gamma rays) knocks off carbon atoms and produces vacancies in the diamond lattice. Those vacancies produce green color centers in pure transparent diamond and yellow-green color in yellow diamonds. Yellow diamonds have it color mostly due to the nitrogen impurity and they constitute the majority of all natural diamonds. Heating those irradiated diamonds to temperatures above 600 °C results in brown color associated with aggregation of the vacancies, with or without nitrogen involved.
Such irradiation and annealing treatment can occur in nature because diamonds are often accompanied by uranium-containing ores which emit alpha particles. However, the thus produced color is restricted to a thin surface layer of few micrometers.Homogeneous color can be produced if the treatment was performed artificially, using electrons, neutrons or gamma-rays. Radiation treatment induces characteristic sharp optical absorption lines which can be easily detected by spectroscopic techniques
Famous brown diamonds
- Golden Jubilee Diamond is currently the largest cut diamond in the world. it was found in 1985 as a rough stone of 755.5 carats (151 g) in the Premier mine, South Africa - one of the most famous diamond mines in the world operated by De Beers. The stone was cut into a 545.67 carats (109.13 g) gem and has been purchased from De Beers by a group led by Henry Ho of Thailand in 1995. The Golden Jubilee Diamond was named by King Bhumibol Adulyadej and given to him on occasion of his 50th coronation anniversary.
- Earth Star Diamond was found at another South African mine of De Beers, the Jagersfontein Mine on May 16, 1967. The diamond came from the 2,500-foot (760 m) level of the volcanic diamond-bearing pipe. The rough gem weighed 248.9 carats (49.8 g) and was cut into a 111.59 carats (22.32 g) pear-shaped gem with a strong brown color and extraordinary brilliance. The diamond was bought in 1983 for $900,000.
- Star of the South (original name was Portuguese "Estrela do Sud") is one of the largest diamonds found in Brazil and the first Brazilian diamond to receive international acclaim.[10] The original rough stone was found in 1853 by an African slave woman, for which she received her freedom and life pension. The diamond was cut into a cushion shaped gem weighing 128.48 carats (25.70 g). For long time, the Star of the South was considered as "by far the largest diamond discovered by any woman anywhere", until the Incomparable Diamond was discovered in the 1980s.
- Incomparable Diamond is another African diamond, one of the largest ever found in the world (890 carats or 178 g). A young girl encountered it in 1984 a pile of rubble collected from old mine dumps of the nearby MIBA Diamond Mine, Democratic Republic of the Congo. The rubble was sorted out during the recovery process because it was considered too bulky to contain diamonds. This massive diamond was considered to be cut into the world largest gem, but finally, the size was reduced to 407.5 carats for the sake of having less internal flaws; nevertheless, it was the 3rd largest cut diamond after the Cullinan I and Golden Jubilee Diamonds. Before cutting, the stone was the largest brown diamond and the fourth largest diamond of any color ever discovered after the Cullinan (3106.75 carats), Excelsior Diamond (995 carats) and Star of Sierra Leone (968.9 carats).The stone was cut by a team led by Marvin Samuels, who co-owned the stone along with Donald Zale of Zales Jewellers and Louis Glick. In November 1984 the finished stones were put on display: a single golden diamond of 407.48 carats (81.50 g) in a 'triolette' shape, and fourteen additional gems. Notably, the satellite stones cut from the Incomparable varied greatly in color, from near-colorless to rich yellow-brown. The largest of these stones still bears the name 'Incomparable Diamond', and was graded by the GIA as internally flawless in 1988.
- Lesotho Brown was unearthed at the Letseng diamond mine in Lesotho in 1967 at Letseng-la-Terai by Ernestine Ramaboa. The rough stone weighed 601 carats (120 g) and was cut in 1968 into 18 polished diamonds totaling 252.40 carats (50.48 g). The largest was a 71.73 carats (14.35 g) emerald cut known as the Lesotho I. The Lesotho III (the third largest stone cut from the crystal) is a 40.42 carats (8.08 g) marquise-shaped gem that was once owned by Jackie Kennedy, given to her by her husband Aristotle Onassis. The ring had an estimated value of $600,000 US, but at the Jackie Kennedy estate sale auction in April 1996 it reached a price of $2,587,500 US dollars. It was mounted in a platinum ring created by Harry Winston. The Lesotho I was offered at Sotheby's, Geneva on November 19, 2008 as part of a Magnificent Jewels sale, but it did not sell. It'd had a presale estimate of 3,360,000 to 5,600,000 Swiss francs, which equated to $2,783,894 to $4,639,824 US dollars. The lot's description mentioned it was being offered for sale by the same owner who had originally bought it from Harry Winston around 1969. It also listed the gem as having a clarity of VVS2, excellent polish and excellent symmetry, and although the stone (and the other Lesotho fragments) is a pale brown color, no color grade is mentioned in the auction text. This might have been deliberate on Sothebys part, so as not to detract potential buyers, since pale brown diamonds traditionally aren't as valuable as colorless and near-colorless diamonds.
Brown diamonds
The majority of natural diamonds are brown in color which makes them less attractive as gemstones. Australian diamonds, which constitute one third of the world production, are especially rich in brown stones. Large amount of scientific research was spent to understand the origin of the brown color. Several causes have been identified, including irradiation treatment, nickel impurities and lattice defects associated with plastic deformation, the latter are considered as the predominant cause, especially in pure diamonds. A high-pressure high-temperature treatment has been designed to heal those lattice defects and convert brown diamonds into yellow or even colorless stones.
Synthetic Diamond
Synthetic diamond is diamond produced in a technological process as opposed to natural diamond, which is created in geological processes. Synthetic diamond is also widely known as HPHT diamond or CVD diamond where HPHT and CVD refer to the production method, namely high-pressure high-temperature synthesis and chemical vapor deposition, respectively.
Numerous claims of diamond synthesis were documented between 1879 and 1928; every attempt has been carefully analyzed and none has been confirmed. In the 1940–1950s, systematic research began in the United States, Sweden and the Soviet Union to grow diamond using CVD and HPHT processes. The first reproducible synthesis was reported around 1953. Those two processes still dominate the production of synthetic diamond. A third method, known as detonation synthesis, has entered the diamond market in the late 1990s. In this process, nanometer-sized diamond grains are created in an explosion of carbon-containing explosives. A fourth method, treating graphite with high-power ultrasonic radiation, has been demonstrated in the laboratory, but has no commercial use yet.
The properties of synthetic diamond depend on the details of the manufacturing processes, and can be inferior or superior to those of natural diamond; the hardness, thermal conductivity and electron mobility are superior in some synthetic diamonds (either HPHT or CVD). Consequently, synthetic diamond is widely used in abrasives, cutting and polishing tools and in heat sinks. Electronic applications of synthetic diamond are being developed, including high-power switches at power stations, high-frequency field-effect transistors and light-emitting diodes. Synthetic diamond detectors of ultraviolet (UV) light or high-energy particles are used at high-energy research facilities and are available commercially. Because of its unique combination of thermal and chemical stability, low thermal expansion and high optical transparency in a wide spectral range, synthetic diamond is becoming the most popular material for optical windows in high-power CO2 lasers and gyrotrons.
Both CVD and HPHT diamonds can be cut into gems of various colors: clear white, yellow, brown, blue, green and orange. The appearance of synthetic gems on the market created major concerns in the diamond trading business, as a result of which special spectroscopic devices and techniques have been developed to distinguish synthetic and natural diamonds.
Synthetic Diamond
Synthetic diamond is diamond produced in a technological process as opposed to natural diamond, which is created in geological processes. Synthetic diamond is also widely known as HPHT diamond or CVD diamond where HPHT and CVD refer to the production method, namely high-pressure high-temperature synthesis and chemical vapor deposition, respectively.
Numerous claims of diamond synthesis were documented between 1879 and 1928; every attempt has been carefully analyzed and none has been confirmed. In the 1940–1950s, systematic research began in the United States, Sweden and the Soviet Union to grow diamond using CVD and HPHT processes. The first reproducible synthesis was reported around 1953. Those two processes still dominate the production of synthetic diamond. A third method, known as detonation synthesis, has entered the diamond market in the late 1990s. In this process, nanometer-sized diamond grains are created in an explosion of carbon-containing explosives. A fourth method, treating graphite with high-power ultrasonic radiation, has been demonstrated in the laboratory, but has no commercial use yet.
The properties of synthetic diamond depend on the details of the manufacturing processes, and can be inferior or superior to those of natural diamond; the hardness, thermal conductivity and electron mobility are superior in some synthetic diamonds (either HPHT or CVD). Consequently, synthetic diamond is widely used in abrasives, cutting and polishing tools and in heat sinks. Electronic applications of synthetic diamond are being developed, including high-power switches at power stations, high-frequency field-effect transistors and light-emitting diodes. Synthetic diamond detectors of ultraviolet (UV) light or high-energy particles are used at high-energy research facilities and are available commercially. Because of its unique combination of thermal and chemical stability, low thermal expansion and high optical transparency in a wide spectral range, synthetic diamond is becoming the most popular material for optical windows in high-power CO2 lasers and gyrotrons.
Both CVD and HPHT diamonds can be cut into gems of various colors: clear white, yellow, brown, blue, green and orange. The appearance of synthetic gems on the market created major concerns in the diamond trading business, as a result of which special spectroscopic devices and techniques have been developed to distinguish synthetic and natural diamonds.