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The Letseng mine in the small Kingdom of Lesotho, South Africa has just uncovered another massive diamond rough: a 198-carat stone, roughly the size of a large strawberry.
A diamond over 100 carats is rare enough – with only about 10 to 15 found each year worldwide – but a rough that is nearly 200 carats is an exceedingly rare find. A stone of this size is expected to yield a polished diamond around 100 carats, or half the weight of the rough it originated from.
Even though the stone’s size is impressive, it is not even close to being the largest ever uncovered from the Letseng mine. In fact, the Letseng mine is well-known for churning out large, quality rough over the years, and has the highest price per carat production of all the mines in the world. Some of the largest include the Lesotho Promise, the 15th largest diamond in the world at 603 carats; the Letseng Legacy at 493 carats, and the Leseli La Letseng at 478 carats which are 18th and 20th largest respectively.
What makes this rough even more valuable is its’ designation of Type IIa, which constitutes less than 2% of all natural diamonds. Type IIa diamonds have no measurable nitrogen impurities, making them chemically pure. This not only gives them exceptional optical transparency, but also a high likelihood of achieving a colorless (D-E-F) grade and a high clarity grade. Officials from Gem Diamonds Ltd, which own the majority stake in the Letseng mine, confirmed this after inspection of the stone noting it as “an exceptional white, high-quality diamond that displays no fluorescence”.
Martin Potts, a London-based mining analyst has estimated the 198 carat stone to fetch somewhere between $12 to $15 million.
Tags: carat, clarity, colorless, cut, diamonds, Gem Diamonds, Golconda, impurities, kimberlite, largest, Lesotho, Lesotho Promise, Letseng Legacy, Letseng mine, mining, pipes, polished, price per carat, raw diamond, rough diamond, sattelite, South Africa, Type II, Type IIa
With its range in color from sunny yellow to bronze deep orange hues, what better stone to represent the falling leaves of autumn than citrine? One of the official birthstones of November, citrine is a member of the mineral family quartz.
Currently the world’s largest faceted citrine resides in the “Special Exhibit Gems” of the Art Natura museum in Spain, a natural science museum that is home to an extensive collection of colored gemstones. Known as “The Malaga” in tribute of its host city, this oval shaped gem is an enormous 20,200 carats – equivalent to 4 kilos! It neighbors another gemstone of gigantic proportions: the “Eldorado”, a 31,000 carat imperial topaz which also happens to be the other birthstone of November.
Despite its size, “Malaga” has very minor imperfections and is considered nearly flawless. Along with its exceptional color, even distribution, transparency and purity, “Malaga” is truly a world-class gem. Citrine crystals that are found usually measure only a few cm across, and the ones that are larger in size generally lack in quality and are used for decorative purposes rather than jewelry.
The rough that formed “Malaga” was originally discovered in 1990 in Brazil. Due to the complications of the process of cutting and polishing a stone this large, the rough was left untouched for nearly two decades until 2009 when a team of gem cutters took on the challenge. With all of the special considerations needed for a stone of this size, it took over a year to bring to its polished form.
Brazil is the largest producer of the world’s supply of citrines; other important sources include Bolivia, United States, and Madagascar.
Tags: amethyst, Brazil, citrine, largest gemstones, Malaga, mineral family, museum of natural history, quartz, tourist sites
The New York Museum of Natural History is having an exhibition for the rare 19th century 55 carat diamond that was once part of the Russian Crown Jewels.
The stone is named “Kimberley Diamond” after the Kimberley Mine where it was discovered in South Africa in 1868. It had been cut from a 490 carat crystal. In 1921 it turned into a 70 carat gem and later in 1958 was re-cut and improved for brilliance and proportions. In the re-cutting process the stone lost some weight 14.92 carats. Now weighing 55.09 carats it was valued at $500,000 but is probably worth considerably more now.
Kimberly Diamond has been perfected to a champagne coloured, emerald cut, rectangular flawless diamond. It is about 1.25 inches in length. It has been described as a “cape diamond” which is an Old World term meaning “deep colour.”
In order a diamond to survive the Earth’s surface it has to get there really fast this stone got a ride on magma. Magma starts very deep in the earth and moves towards the surface at 35-40 km/h. During a volcanic eruption the magma creates bubbles like champagne and can reach speeds up to Mach 2 (twice the speed of sound).
Diamonds were first found along rivers where people would look for gold. In the 1870’s lots of diamonds were found at the bottom of rivers and streams in South Africa. They would follow the river upstream and find a grey blue rock which contained a diamond. Now days a gem the size of the Kimberley diamond wouldn’t survive in modern mining techniques it would be crushed in the process.
The diamond will be on display with “Patricia Emerald” and “The Star of India.” Patricia Emerald is a 632 carat 12 sided emerald crystal from Columbia. The Star of India is the world’s largest gem quality blue star sapphire it is 526 carats in weight and is 2 billion years old!
Kimberly Diamond is on loan from Bruce T. Stuart. The stones will be added to the Morgan Memorial hall of Gems and is on display in the NYC museum through to June 2014.
Tags: 55 carat, blue star, carat, champange colour, diamond, emerald cut, flawless diamond, gem, gem quality, gold, kimberley, kimberly diamond, kimberly mine, mach 2, mining, museum of natural history, new york museum, new york museum of natural history, nyc museum, proportions, rare stone, russian crown jewels, sapphire, south africa mine, star of india
A treasure that was uncovered 100 years ago by a workman is going to now be on display for the first time next fall in the Museum of London. The entire chest called the Cheapside Hoard which includes hundreds of gold and gem studded Tudor and Jacobean jewellery. There are many questions and possible murder mystery tales surrounding this jewellery which makes its value more than just its weight in gold. It also can tell us about the life during this time in London a period from between 1558 to 1625. Some questions that arise are whose jewels were these? Why was it hidden? Why hasn’t it ever been claimed?
It was first discovered in 1912 when it was buried in a cellar on Cheapside in the City of London. A workman’s pickaxe smashed through the brick floor more than a century ago and it was left forgotten. When an old house was being demolished on Cheapside the hoard was found and remains priceless.
“Nothing in the world comes close,” said Museum of London curator Hazel Forsyth. He has been studying the pieces for a long time now. Some of the jewelry includes necklaces, rings, brooches, chains, pearls, rubies, fan holders, scent bottles and two carved gems dating back 1,300 years ago. The most delicate of items are fine gold enamel chains with gems on them up to two meters long they were stitched on gowns and hung from collar to waist as a dazzling display. “This collection has been misunderstood and misinterpreted, dismissed as jewelry for the merchant classes,” Forsyth said. “But at this date the merchants were among the wealthiest people in the land; they had far more disposable wealth than the aristocracy.” Along with the massive rubies, and pearls the size of acorns there are sapphires, emeralds and some fake stones made of quartz crystal which have been dyed and carved to look like precious gems.
New research of a specific gem known as “The Stafford Intaglio”, an oval shaped piece of engraved cornelian, suggest the time it was buried between 1640 and 1666. The engraved piece is a badge of Stafford with a swan and a wreath, there was only one Viscount Stafford by the name of William Howard in 1640.
Two other pieces from the Cheapside Hoard is a salamander shaped brooch set with Colombian emeralds and table cut diamonds from India. The other is a gold enamel ring set with moonstone and engraved with a frog.
Another extremely rare piece is a hexagonal emerald watch, one of the most unusual and decadent pieces found, one of a kind no other in its era had ever been recorded.
All these jewels will be displayed together they are the single most important knowledge of early modern jewelry worldwide.
Tags: brooch, city of london, cornelian, cut, diamond, gold, gold enamel, hazel forsyth, intaglio, jewel, museum of london, mystery tales, necklace, pearls, precious gems, quartz, quartz crystal, rare, ring, rubies, sapphire, shape, stone, tudor and jacobean jewellery
Sapphires come in every colour except a certain shade of red called a ruby. There are several different methods to enhance and improve the colour and clarity of a sapphire. Commonly practiced treatments are heating a natural sapphire to heighten the look of the stone. Heating a sapphire is done by placing it in a furnace at temperatures between 500 and 1800°C for several hours. Another way is by heating it in a nitrogen-deficient atmosphere oven for seven days or more. With this process the stones become bluer and lose some of their inclusions like the silk kind. When higher temperatures are used the stone loses all silk inclusions and under magnification the stone is clear. Sapphire and other gemstones being heat treated goes back to Roman times. An untreated natural stone is somewhat rare and will be sold with a certificate from a gemology lab.
Another treatment is diffusion to add impurities to the sapphire and enhance the colour. A type of chemical element called beryllium is diffused into the sapphire with very high heat. Many colours of sapphires are being treated with beryllium. At first orange sapphires were created with this process but now the process has been advanced and many different colours can be produced.
On the other hand a type of sapphire called “Yogo” sometimes does not need to be heat treated because of their natural cornflower blue colour. These sapphires have a deep blue uniform clarity and are generally free of any characteristics or inclusions. Intergem Limited started marketing the Yogos in the 1980’s as the world’s only untreated sapphire guaranteed. By 1982 heat treatment became a major issue at that time 95% of all the worlds sapphires were being heated to bring out their natural colour. The guarantee of Intergems marketing of Yogos set them apart of many in the gem industry. The issue ended up on front page of the Wall Street Journal in 1984 with the headline “Sapphire Marketer Upsets the Gem Industry.”
How to tell if your sapphire has been heat treated? Usually a small UV lamp can help check the gem quickly for any potential alterations. Any stones that have a chalky florescence are most likely heat treated. Taking it to a certified gem dealer with GIA industry standards is a good way to have them test it.
Tags: beryllium, blue colour, chemical element, clarity, furnace, gem industry, gemstones, GIA, heat treatment, high heat, impurities, inclusions, magnification, natural colour, natural sapphire, roman times, stone, untreated sapphire, yogos
The most flawless, biggest briolette ever to surface at auction weighing at a stunning 75.36ct broke records! This diamond was sold for a world record at $11,145,734 from an anonymous buyer at Christie’s Hong Kong’s Magnificent Jewels sale. This pendant necklace was originally valued at a pre-sale low estimate of $8.5 million, which it easily surpassed. It did fall short of its high pre-sale estimate of $12.5 million.
The briolette is a traditional cut popular in the Victorian times but has recently become more popular in precious and semi-precious stones. It is a stone cut into a three-dimensional waterdrop shape. Its elegant pear shape with cut facets dangles below a marquise-cut purplish-pink diamond. Adorned with stations of smaller briolettes with 18 karat white and rose gold adjustable neck chain, this piece is a classy stunner!
An auction spokesperson said the diamond was “perfect,” and had the proof of an assessment with the Gemological Institute of America. The GIA rated the stone Type IIa, which is the top quality grade. The diamond is similar to the British Queen Elizabeth’s one she has set in her crown. Christie’s jewellery specialist, Chiang Shui-Fung, says the diamond is extremely rare.
The briolette is special because they have to find a piece rough and big enough to cut into that style. The diamond came to an American dealership named William Goldberg, as a 160.5- carat rough weight and had to be shaped into the now 75.51 carat diamond. To achieve this brilliant rare cut William Goldberg had to sacrifice more than half the stone’s weight in the meticulous cutting process. The diamond is now a stunning piece and will be remembered as a historical record breaking event.
Tags: 18 karat, briolette, briolettes, carat diamond, christie, crown, flawless, gemological institute of america, goldberg, jewel, magnificent jewels, marquise, million, necklace, pear shape, perfect, quality grade, sale, size, stone, stunner, Type IIa, victorian, victorian times, waterdrop, world record
The Australian Argyle Diamond Mine will feature three ultra-rare red diamonds in the upcoming Pink Diamond Tender. This is the most it has featured in 30 years. They began mining in 1983 and only six diamonds have come out of the mine as certified Fancy Red by the Gemological Institute of America. This is a very notable time for red diamonds.
Also for the first time in eight years it will feature a diamond bigger than 3 cts: a 3.02 ct. fancy pink radiant going by the name of “Argyle Imperial.” There is another weighing at 1.56-carat which is round fancy red called the “Argyle Phoenix.”
Josephine Johnson Argyle Pink Diamonds Manager had this to say about it. “Since mining began in 1983 only six diamonds certified as fancy red by the Gemological Institute of America have been presented for sale at the annual tender. To have three of these rare red diamonds in one tender is a very special moment in time.” They will be presented for sale at the annual tender. The diamonds will have their world debut first in Sydney. Then tender viewing will take place in Hong Kong, Perth, and previews in Tokyo and New York with bidding closing in October. All vividly naturally coloured diamonds are expensive but red diamonds are so rare that many think their price might double in the next couple of years.
The Argyle mine produces the world’s entire supply of pink diamonds with the red seen as the top pinnacle of the colour scale. Japan is the largest consumer of pink diamonds since the cherry blossom tree inhabits the land there the shade of pink is highly favorable to them.
Fancy red diamonds are the rarest naturally coloured diamonds. Very few diamonds receive a grade of fancy red. This grade of fancy red means that the diamond is pure red and has no modifying colour. No one really knows how the diamond gets to be this colour. It is thought that it gets its colour from a molecular structure distortion as the jewel journeys up from the crusts earth to the surface. Another thought is that the diamond could get its colour from nitrogen atoms. Diamonds are made up of carbon atoms bonded together, sometimes there are gaps within these atoms and scientists think that the gaps and nitrogen cause the red colour. They are shaped by millions of years of crystallization. Either way the natural colour of a fancy red is unmistakable and breath taking. Diamonds come in different colours including, champagne, yellow, pink, red and purple. Natural and treated colour diamonds are two completely different markets.
Check out a local jewellery boutique store for more information and to view some different coloured diamonds in a variety of shape and cut. If you are looking for that perfect custom diamond to add to an engagement ring its best to shop at a local jewellery store where they have trusted customer service and can help you find the exact unique coloured stone that’s right for you.
Tags: argyle diamond, argyle mine, carat, colour scale, coloured diamonds, diamond mine, gemological institute of america, jewel, pink diamond, pink diamonds