Thursday, September 25, 2014

Pink Diamond

Estimated Value $30,000,000.00

The origin of the name "Pink Sunrise"is unknown as are other important details of this rare and unique diamond which first made it's appearance at the beginning of the 21st century. Perhaps, the name seems to reflect the unique color of this diamond, which is reminiscent of the shades of pink and red colors associated with the sun's appearance in the early morning eastern skies.


Characteristics of the diamond 

The "Pink Sunrise"is a 29.79-carat, fancy pink, internally flawless (IF), diamond, with a modified heart shape, reminiscent of the renowned 273.85-carat, D-color, De Beers "Centenary Diamond", which had an identical shape.
The "Pink Sunrise"is a type IIa diamond. The important features of this class of diamonds are :-
1. They are Nitrogen free or contain undetectable quantities of Nitrogen.
2. The crystals are plastically deformed, which imparts the pink color to the diamonds.
3. They are very rare in occurrence, perhaps much less than 0.1 % of all naturally occurring diamonds.

History

Besides the color, cut, clarity and weight of the diamond, nothing else is known about the early history of the "Pink Sunrise", such as the date of discovery, the country of origin, the mine of origin, the original owners of the diamond, the circumstances of the discovery etc. The only fact we know for certain about the diamond is that it was cut by the world renowned master cutter Gabi Tolkowsky, perhaps in Antwerp, Belgium, and the finished stone was unveiled to the world at the beginning of the 21st century.
A casual inspection of the photographs of the "Pink Sunrise"and the "Centenary"diamonds immediately reveals a striking similarity in their shapes. This similarity is not a matter of coincidence, but caused by deliberate design, as the two stones were cut by the same world renowned master cutter Gabi Tolkowsky, who lives in Antwerp, Belgium, and hails from a family of diamond cutters, with five new diamond cuts to his credit. Gabi Tolkowsky has also earned the rare distinction of cutting the world's largest faceted diamond, the 545.67-carat, fancy yellow brown, IF clarity, cushion shaped diamond, the "Golden Jubilee", which was presented to the King of Thailand, by his subjects in 1997, to mark the Golden Jubilee of his Coronation. Tolkowsky referred to the cushion-cut employed on the "Golden Jubilee"as a "fire rose cushion-cut."
According to Gabi Tolkowsky, the "Pink Sunrise"was the first rare and unique historical diamond, that was ready to appear at the beginning of the 21st century. The cutting and polishing of the "Pink Sunrise"into a modified heart shape took more than an year, in spite of the smaller size and carat weight of the rough stone. Even though the shape of the two diamonds were strikingly similar, the "Pink Sunrise"had it's own individual beauty, with it's own pattern of facets and design.
Gabi Tolkowsky is reported to have said that the inspiration which he gets to select an appropriate design for a rough stone, from a range of available cuts, result from an imposed fact. According to him, "every diamond large or small is a unique individual. None is similar to another. The shape, volume, hue and purity in the rough appearance have a combined effect on the mind. All what happens is the fact of revolving the rough stone between two or three finger and peering onto and into it, with the small folding hand loupe."The greatest challenge to the cutter is to reveal the hidden potential and beauty of the rough stone by selecting the appropriate cut.
Perhaps being a new discovery, the stone doesn't have any legend or history associated with it, but without any doubt it has the potential of becoming a famous diamond, and building it's own legends as it passes down from generation to generation.

Occurrence of pink diamonds

Pink diamonds are extremely rare in occurrence. There are only about ten notable and famous pink diamonds in the world today, and almost all of them are less than 100 carats in weight. Even the smaller pink diamonds such as the ones produced in the Argyle Mines in Australia, are also extremely rare. A statistical estimate at the Argyle Mines in western Australia has shown that only a single carat of pink diamond is produced for every 1,000,000 carats of rough diamonds. This woks out to an astonishingly low percentage of 0.0001 %.
The earliest known source of pink diamonds in the world was the Kollur mines near Golconda, in Southern India. The Darya-i Nur, Nur-ul-Ain, Hortensia, and the Conde Pink might have originated in these mines. The next known source of pink diamonds were the diamond mines of Southern Africa. The Steinmetz Pink, Mouawad Lilac and the Mouawad Pink might have originated in these mines. Today the Argyle mines of western Australia have become a consistent source of pink diamond even though they are much smaller in size and have an average weight of about one carat. In spite of their smaller size the Argyle pink diamonds are noted for their intense pink colors which are superior to the lighter shades of pink, of diamonds from other traditional sources. At a Christie's auction in New York in 1989, a 3.14-carat Argyle pink diamond was sold for $ 1,510,000. This works out to about $ 480,000 per carat. But, privately Argyle had sold pink diamonds for up to $ 1,000,000 a carat.

List of famous and notable pink diamonds arranged in descending order of weights

S/N
NameCarat WeightShape/Cut
Color
1Darya-i-Nur186.00tablelight pink
2Nur-ul-Ain60.00ovallight pink
3Steinmetz Pink59.60cushionfancy vivid pink
4Shah Jahan56.71tablelight pink
5Agra32.34cushionfancy light pink
6Pink Sunrise29.79mod. heartfancy pink
7Mouawad Lilac24.44emeraldfancy pink
8Graff Pink Orchid22.84marquisefancy purplish pink
9Mouawad Pink21.06radiantfancy pink
10Hortensia20.00pentagonallight orangish pink
11Graff Pink Supreme10.83fancy pinkpear
12Conde Pink9.01light pinkpear

Sunday, September 21, 2014

Beyond a GIA certificate The Factors of Value

The Factors of Value
By Mark Prendergast
Find him on 
In order to properly value an object, whether for a formal appraisal or for estimates of value at auction, a number of factors must be considered. The primary determinants of value are provenance, rarity, condition, quality, and fashion/market trends. No one feature alone can determine a value, though there are occasions when one aspect is much more heavily measured. The more desirable and prized each factor is in the particular market, the more 'valuable' an object will be.
Provenance — The provenance of an item is the record of the people and places that an object has encountered throughout its existence. Provenance is not just who owned it but also where it has lived, where it was exhibited and who handled its sale in the past. An objects association with a famous person or renowned collector can greatly increase its desirability in the market, and thus its value. The prices achieved during the highly publicized auctions of the personal property of such iconic figures as the Kennedys, Marilyn Monroe or Martin Luther King do not necessarily reflect the inherent values of the objects themselves but much more the value of the connection the object has to the famous person — and ultimately history. Martin Luther King Jr.'s cane rocking chair is being offered for sale in November 2009 at Heritage's 20th Century Icons auction. The chair was used by Dr. King during the writing of some of his seminal late 1960's books and comes to auction through the family of his literary editor. A similar chair from the period is worth a few hundred dollars, while the King associated chair is expected to bring some $12,000.
Rarity — Rarity is a consideration that can truly drive up the price of an object but can also be limiting in extreme instances. The rare "Inverted Jenny" stamp is heavily sought by collectors as the holy grail of stamps. A mistake in the 1918 printing of the two-color stamp has the image of a Curtis JN-4 "Jenny" airplane mistakenly depicted upside down. Only a single sheet of 100 of these stamps survived the initial erroneous printing. When government officials demanded the stamps back, the original buyer wisely held his ground, and later sold the sheet of stamps, which were subsequently split apart and sold individually. The fact that there have only ever been100 of these stamps creates a limited and finite supply. Individual "Inverted Jenny" stamps see six figure prices, while the best preserved examples come close to a million dollars.
Without a traceable history of related sales, the value of an item might be undeterminable or minimized. Independent rarity — being the only example in the world — can be limiting in the fact that there is not an identifiable market for the item. If you have the only one of something — without relative comparable examples in the market, the likelihood of finding a willing buyer at a healthy price is difficult, if not unlikely.
Condition — Condition of an object can bear heavily on value. Using the "Inverted Jenny" example, the value of each stamp, or group of stamps, is based on the condition. Whether they have been hinged, damaged, creased, worn or the gum has been disturbed, all factor into the desirability to collectors. For stamps and coins, where there are means of formalized grading of condition, the condition is rated in a numeric scale that can mean the difference of hundreds, thousands, or, as in the case of the "inverted Jenny", hundreds of thousands of dollars in value.
In art and antiques, condition also can play a key role in determining value. We have all heard the stories of early American furniture pieces being heavily cleaned by an eager owner only to find that the value of the piece was washed away with the years of grime and dirt — more eloquently referred to as the 'patina'. Paintings and antiques can often be restored to return them to a pristine or at least more marketable state. A heavily soiled painting cleaned professionally can look like a completely different work of art and become much more desirable to collectors. Of course, a painting or antique requiring no assistance will hold the most value, but in many instances value can be increased and recouped through the conscientious attention of a skilled restorer. Auction houses and art experts can provide insight into the benefit — or detriment — of having an item's condition improved.

Considered by collectors to be the top quality 'pin-up' artist, Gil Elvgren paintings are selling at record prices in Heritage's Illustration Art auctions.
Quality — The intrinsic quality of a work of art or collectible can determine whether it will retain or increase its value over time. The best quality items tend to appreciate and retain value most easily. Quality is sometimes very subjective as it can be maximized or minimized according to the tastes and appreciation of an era. Top workmanship, the best means of production and the most skilled artisans — no matter the period, category or collectible — will result in the highest quality object. A painting regarded as a very high quality example of its style, independent of the artist associated with it, can fetch very high prices on its artistic quality alone. Conversely, a very poor quality work by a famous artist will be much lower in value than a painting that is considered one of their masterpieces. Many artists had bad days or even periods when their production is not recognized to be of the best quality.
Fashion — People's tastes and opinions of worth can vary from decade to decade — if not year to year. Collector's must be careful not to be too swept up in the trends and escalating prices in certain markets. Changes in attitudes and styles will be reflected in swells and corrections in values. The Post-War and Contemporary Art market saw staggering increases in value consistently from 2004 to mid-2008. It was in vogue to buy works by the "hot" artists of the moment — with collectors driving prices at auction to many multiples of the pre-sale estimates. Some speculative and aggressive collectors are known to pay trendy artists in advance to be on a list for works that have not yet been produced or even conceived. The question now remains if the fashions and trends that drove prices during the heady times of economic potency will continue into a more subdued, cautious market.
The art and collectibles market is directly affected by the larger economic trends, but as in any market there are higher risk/reward areas and more consistent 'blue chip' segments. The rare coin market as a whole has not seen the dramatic effects of the economic downturn, and is proving to strengthen as the price of gold and interest in diversifying portfolios increases.
Today's expansive access to information allows for almost anyone to find databases that chart and record the sales or market prices of objects and art. From coins and stamps to artwork and diamonds, there are internet sources to track the going markets. All these resources are crucial in determining value. What becomes more of an art in itself is using the aspects of value discussed in this article to see where a particular item fits into the hierarchy of value. That is the art of appraising.
In some instances, rarity, condition, provenance and quality all converge during the ideal moment of fashionablilty. When all factors of value are embodied in the right object, incredible prices are achieved. Such a 'perfect storm' of value is seen when over $3.7 million is paid for a silver dollar (1804 Class I Original), $20 million is paid for a crystal egg (Imperial FabergĂ©) and $140 million is reportedly paid for a 1948 painting (Jackson Pollock's No. 5).

Inside Sapphires



This article has been reprinted with permission from the American Gemological Laboratories (AGL).
Originally Published on the Rapaport Diamond Report, July, 2010 / Vol. 33, No. 07

By Christopher P. Smith, American Gemological Laboratories AGL


Through the ages, blue sapphires have been one of the most highly revered, sought-after and valued gems. This tradition continues today, as evidenced by the recent, June 1, 2010, Christie’s Hong Kong auction of a remarkable bracelet containing seven Kashmir sapphires that sold for a record-breaking $6,915,624. Historically, gems, including sapphires, were a primary expression of the wealth of the ruling class, demonstrating the power of rulers, the opulence of their courts and the richness of their nations’ treasure troves to fund exploration and colonization, as well as wars. Gems also have been used throughout time as an inheritance, in order to transfer wealth from one generation to another. In modern society, sapphires adorn celebrities, inspire jewelry designers and continue to be an expression of love and devotion.
Cartier sapphire bracelet circa 1960
Cartier sapphire bracelet circa 1960
The blue color of sapphire may be found in many evocative shades, ranging from the soft pastel of cerulean to richly saturated indigos. Ancient lore endowed sapphire with many admirable traits, such as friendship and loyalty, as well as the ability to protect the wearer of the gem. Today, in contrast to the fiery, passionate emotions associated with the ruby’s red color, the blue of sapphire is linked to truth, compatibility, commitment and mutual understanding.  Sapphire is the birthstone for the month of September and, more recently, it has become the stone of choice for many engagement rings.4

Blue sapphire deposits is widely distributed in a variety of geologic conditions, allowing gem-quality stones to be unearthed in greater amounts and in significantly greater sizes than the other members of the corundum family, including the ruby and other color varieties of sapphires, with the occasional exception of large yellow sapphires. Exceedingly rare, fine-quality blue sapphires of several hundred carats have been found and can be seen in a variety of museums, crown jewels and private collections. Some of the most famous examples are the 563.35-carat Star of India, which resides in the American Museum of Natural History, the 423-carat Logan sapphire, housed at the Smithsonian, and the 100-plus-carat Stuart sapphire, incorporated in the British Crown jewels on display in the Tower of London.5’6

THE IMPORTANCE OF ORIGIN
The origin of a gemstone such as Burma for rubies, Colombia for emeralds and Brazil for copper-bearing tourmalines can have a profound impact on its market value. In the case of sapphires, the most highly reputed and valued stones bear the pedigree of Kashmir and Burma. Top-quality sapphires from these sources typically achieve the highest per-carat price at auction.7,8
Very fine sapphires also come from the islands of Sri Lanka (Ceylon) and Madagascar. Sapphires from other sources, such as Pailin, Cambodia, and Yogo Gulch, Montana, have experienced periods of heightened popularity and remain sought after by knowledgeable connoisseurs in various markets around the world.3,9
Although a number of other countries including Australia, China and Thailand are large producers of sapphire in terms of the total carats, mined, the overall quality and provenance of these stones does not command the same elevated status among connoisseurs.
 
Top-quality sapphires from Kashmir and Burma display the two types of colors that are most highly valued today.

PRODUCTION AND AVAILABILITY
Blue sapphires may form under either metamorphic or igneous conditions and are distributed across the globe (see “Key to Sapphire Chart”) .10,11
Ceylon, now known as Sri Lanka, an island off the Southern tip of India, is generally considered to be the world’s first source of sapphires and many other gems with a history that dates back more than 2,000 years.3,5,12   After Ceylon, the Kingdom of Pegu, also known Burma or Myanmar, has been a source of these azure-colored for more than 1,000 years.5,13   The original discoveries of gems in both locations are shrouded in lore and mystery; however, many of the most important sapphires in history maybe traced back to these two very prolific sources. A small, yet continuing, production of sapphires from these deposits is a tribute to the bounty of reserves in these locations, as well as to the benefits, to small-scale, artisanal mining that continues to be employed to unearth these gems.
By the mid-1600s, it appears that southern Thailand, and later the area now known as Cambodia, began to produce both sapphires and rubies. However, due to their use of mechanized mining, within the past few years, Thai deposits have become largely depleted, with little new production. 5,14
A significant discovery of sapphire in 1854 along the Eastern region of Australia has yielded, to date, a number of deposits in both Queensland and New South Wales.5 These deposits, which are hosted in alkali-basalt magmatic beds, still produce significant quantities of sapphire. They are so rich in sapphires that it has been suggested Australia has produced more of that gemstone by carat weight than any other source throughout history.5
Another important sapphire find in the state of Montana in 1865 brought an intriguing but limited source of sapphire to the American market.9 But it was an unexpected find of sapphire in the 1880s in a remote area of the Kashmir region, near the village of Sumjam in Northern India, which has had the most significant and lasting impact on the gemstone trade worldwide. Although the primary period of production for this source was a mere seven years, the yield was extraordinary.5,16   The majority of Kashmir sapphires in the market today were produced during that time. Since the initial discovery, sapphire mining has continued sporadically in the area on a very small scale, unearthing only a few good stones per year.  However, to this day, there is the rare occurrence of a find that yields an important Kashmir stone.
With the exception of Kashmir, collectively Australia, Burma, Ceylon and Thailand/Cambodia were the world’s only significant suppliers of sapphire until well into the twentieth century. Beginning in the 1960s, and continuing to the present, a number of sapphire deposits worldwide are contributing small, yet steady, amounts to the global supply. In East Africa, several sapphire deposits have been uncovered in Tanzania, as well as Kenya and, most recently, Mozambique. China also has emerged as a major supplier of dark, commercial-quality sapphires.
For more than a century, the presence of sapphires was known in Madagascar. But it was only as a result of yet another fortuitous find of sapphires during 1996, near the town of Andranondambo, that the island nation became known as a major global source.17Madagascar’s fine sapphires occur in sizes and qualities to rival those of the most prestigious sources, including Sri Lanka, Burma and even Kashmir. However, as a newer source, Madagascar has not been able to command the same cachet for its sapphires in the marketplace as older, better-established sources.
In addition, periods of controversy and politics often have interrupted the production of sapphire from Madagascar and inhibited the country’s ability to provide a steady supply. Nonetheless, today Madagascar remains one of the most important suppliers of fine-quality blue sapphires and other gems for the gemstone and jewelry trade.18
Several other countries also possess reserves of sapphire that show promise. These include Brazil, Colombia, Laos, Nigeria, Rwanda, Vietnam, Nepal and Pakistan.5,19,20,21

TURNING UP THE HEAT
Much of the gem-quality sapphire available in the market today is heated. Prior to the early 1970s, sapphire heating was restricted to the age-old blow-pipe method and an open flame. However, a chance discovery demonstrated how pale-blue-to-white sapphire could be heated at higher temperatures, under certain conditions, to dramatically improve the color and clarity of a piece of rough. The story of this discovery has become near-legend and varies in its telling, depending on the source. Some say it was a Swiss company that discovered the secret.5  However, most tales generally revolve around an accidental fire that took place in Chantaburi, Thailand, at the house of an important gem merchant. In the aftermath of the fire, sifting through the ashes of what had been his home and place of business, the Thai gem dealer found hordes of previously discarded low-quality sapphire that had miraculously become crystal clear, with a vibrant blue color, in the heat of the fire.  This tale maybe fact or fiction, but it is fact that during the 1970s  Thailand became known for low-grade sapphire, locally known as geuda, to produce sapphires of a strong blue color.   Today there are many sub-classifications of geuda such as, milky, silky, diesel and others – which the treaters distinguish and heat under specific conditions.5,22

This heating can improve the clarity of a stone by dissolving fine inclusions that reduce transparency and greatly enhance the color by enabling the pairing of iron and titanium atoms to occur, which is the mechanism responsible for the blue color in sapphire
(see “Key to Sapphire Chart”).

Blue sapphire, regardless of its origin, whether natural-color or heated, continues to be one of the most popular colored stones sold at retail. Although top, gem-quality sapphires from the world’s premier sources are becoming increasingly rare, newer deposits and improved heating procedures help to meet demand and promise additional, sustainable supplies for many years to come.


SAPPHIRE SOURCES
Deposits of gem-quality sapphire can be found in approximately 20 countries around the world. These deposits are not randomly distributed, but their locations are closely linked to major geologic events and plate tectonics. The preponderance of sapphire deposits occur in three geologic settings.
The first involves the orogeny or mountain-building event that is responsible for the creation of the Himalayan mountain chain— and several other associated mountain ranges— which occurred when the Eurasian and Indian plates collided approximately 55 million years ago. These sapphire deposits extend from the remote areas of Afghanistan, Pakistan and Kashmir in Northern India, through Nepal into Burma and across to Vietnam. Many of these areas are producers of gem-quality ruby as well. (See “Inside Rubies,” published in Rapaport Diamond Report, December 5, 2008,Vol. 31, No. 47.)

The second major geologic event that is responsible for a number of sapphire deposits, as well as other gems, includes the Pan-African orogeny, estimated to have taken place approximately 800 million to 450 million years ago. This mountain-building process occurred prior to the separation of a large landmass known as Gondwana, when what are presently Eastern Africa, Sri Lanka, Madagascar and India were all united. This event is responsible for the sapphire deposits of Sri Lanka, Madagascar, Kenya, Tanzania, Mozambique and others.
A number of sapphire sources are also associated with eruptive events at the continental margin of the Pacific plate’s western edge. Along this subduction zone, erupting alkali-basalt magmas have intersected sapphire occurrences and transported them to the surface. These sapphire sources include Thailand, Cambodia, Laos, Southern Vietnam and Australia. A number of other countries also have alkali basalt-hosted deposits— commonly referred to as basaltic deposits— that produce sapphires, including China, Colombia, Madagascar, Nigeria and Rwanda.
A seemingly random occurrence of sapphire from a different type of magmatic-related environment hosted by a lamprophyre rock has been found in the state of Montana, in the U.S.

THE GROWTH OF SAPPHIRE
Blue sapphire deposits found around the world have formed under either metamorphic or igneous/magmatic growth conditions. Metamorphism is when preexisting rocks are recrystallized without melting due to changes in temperature, pressure and/or chemical composition on a regional or local scale. A number of specific metamorphic environments are responsible for the growth of sapphires within individual countries or areas. Currently, it is generally accepted that the classical blue, green and yellow sapphires— sometimes referred to as BGY-series— recovered from magmatic or basaltic deposits, have not formed in the alkali-rich basaltic magma where they are found, but they do have an igneous origin. Researchers have proposed that corundum could crystallize directly from certain volatile-rich magmas that are silica-poor and alumina-rich rocks under restricted conditions present in the upper mantle.
Gem-quality sapphire deposits are typically categorized into two main groups: metamorphic and magmatic-related.
Metamorphic deposits: These sapphire deposits are primary sources, meaning these sapphires actually formed in the host rock in which they are found. The host rock is commonly a marble, schist or gneiss and can be associated with shear zones.
Magmatic-related deposits: These sapphires are found in magmas. Magmatic-eruptive events are technically only a secondary source because the erupting magma is merely the transport mechanism that brings the sapphires to the earth’s surface and not the host rock in which the sapphire formed. Since the sapphires are recovered at the surface in the magma flow, many people have incorrectly considered this type of deposit to be a primary source. However, it is more appropriately considered another kind of secondary deposit.

SOURCE TYPE TYPE CLASSIFICATON
A system of classification was developed by C. P. Smith, author of this article— while director of the Gubelin Gem Lab in Switzerland— that combines geologic and gemological considerations in order to compare sapphires with various properties and internal characteristics forming in similar growth environments. This system allows for sapphires of similar “types” but from different countries to be compared, as well as sapphires of different “types” to be distinguished from each other. This classification can also be applied to rubies. (See “Inside Rubies,” published in Rapaport Diamond Report, December 5, 2008,Vol. 31, No. 47.)
The classification system has two tiers. The first tier separates sapphires into three groups based on broad geologic formation scenarios. Two of the three groups contain stones that possess what are considered by experienced gemologists to be “classical” combinations of specific gemological features for metamorphic and magmatic-related sources. For the sapphires from metamorphic environments, referred to as Met, such features include a blue color that is primarily due to an intervalence charge transfer between iron (Fe) and titanium (Ti) —Fe2+↔ Ti4+ —with a lesser influence due to iron present as Fe and mineral inclusions such as calcite, apatite, mica and others. The blue of sapphires in this category, although it may be very saturated, is typically lighter or brighter than that of the magmatic- related group. Typical sources for the Met group include Burma (Mogok area), Ceylon (Sri Lanka), Madagascar (both Andranondambo and Ilakaka) and Kashmir in Northern India.
Sapphires from magmatic-related environments, referred to as Mag, have classical features that include a darker blue, often greenish, color and a relatively higher iron content. Common mineral inclusions include uranpyrochlore, ilmenite and niobite-columbite, as well as others. A telltale spectroscopic feature of sapphires in the Mag group includes an absorption attributed to the intervalence charge transfer between Fe2+ and Fe3+ Typical sources of sapphire in the Mag group include Australia, China, Thailand and Cambodia.
A third group designated as Met-Mag indicates those sources that have properties and characteristics outside of the classical ones for either Met or Mag. Such sapphires may be recovered from either a metamorphic or magmatic- related deposit. However, they are characterized by higher iron contents than are typical of Met sapphires and an absence of the Fe2+ ↔Fe3+ intervalence charge transfer in the absorption spectrum. Sapphire deposits that fall into the Met-Mag group include the state of Montana in the U.S., Tanzania— both Songea and the Umba Valley and Colombia.
A subset of sapphires from the classical magmatic-related— alkali basalt-hosted —deposits are actually formed under deep metamorphic conditions and were subsequently caught up in the same eruptive event that brought the igneous-formed sapphires to the surface. Such sapphires are sometimes referred to as “metamorphic-suite sapphires from magmatic sources,” and are also classified as Met-Mag due to their properties and characteristics.
The second tier of the classification system subdivides each of these three groups into four categories or “types” —Type I to Type IV— based on their dominant inclusion features and supported by various other features and data from advanced analytical techniques. Type I stones are typified by “silk” inclusions, generally needles of rutile. Type II are characterized by very fine-grained, zonal clouds of  “dust” particles. Type III may be distinguished by various cross-hatch and flake-like inclusion patterns. Type IV are identified by zircon inclusions and/or crystals associated with thin films. Combinations of these types may occur when multiple features are encountered in a stone.

METHODS OF TREATMENT
As with most gem materials, a variety of treatments can be applied to improve the apparent quality of a sapphire. These range from relatively simple tech- niques to much more advanced methods.
Oiling: Filling of fissures is an enhancement method that dates back to antiquity. In non-heated sapphires, fissures may be filled with an oil or similar substance to reduce their visibility and improve the apparent clarity of the gem.
Heat only: Relatively low-tem-perature heating, such as the blow-pipe method, has been used for centuries. However, modern heating at relatively higher temperatures, using an oven and controlled environments, has been commercially used since about the mid-1970s. Heat alone can be used to modify the color of a sapphire; most commonly, sapphires are heated under reducing conditions to induce or improve the blue color. Additionally, the apparent clarity may be improved, as heating can also dissolve dense concentrations of rutile needles.
Heat +fissure healing: Although not as common a practice as with rubies, sapphires treated by heating combined with the use of fluxing agents are encountered in the market. In addition to modifying the color and dissolving rutile needles, fluxing agents can be used during the heating process to heal fissures. Remnants of flux become trapped inside the stone along the preexisting fissures. Another by- product of this process is that the flux may also fill surface-reaching cavities.
Heat + Ti- diffusion: The tita-nium diffusion of sapphire has been known and available in the industry since approximately the mid- to late-1980s. Under more extreme heating conditions higher temperatures and/or longer duration it is possible to diffuse elements, such as titanium, into the lattice of a sapphire. This will induce a shallow blue color at the surface of a stone.
Heat + Be-diffusion: The beryl- lium diffusion of sapphire took the industry by surprise in 2001. Under these more extreme heating conditions higher temperatures and/or longer duration it is also possible to diffuse beryllium into the lattice of a sapphire. This will induce, modify and/or remove color, depending on the heating conditions, inherent chemical composition of the stone and the amount of beryllium introduced.
Cobalt-glass fissure in-filling: In recent years, a method was developed to dramatically improve the apparent clarity of low-quality ruby by infusing it with a high refractive index lead glass. Consequently, a cobalt-blue colored glass has been used to induce a blue color in low-grade corundum and improve the apparent clarity.This treatment is primarily seen in low-quality beads.
Cobalt coating: Although not widely available, neon-colored blue corundum has been occasionally encountered in the gemstone trade that owes its color to an amorphous coating containing aluminum and cobalt. The color of these stones is unlike anything naturally encountered in sapphire.


REFERENCES
(1) Christie’s Jewels Sale Fetches $60M in Hong Kong – http://www.rapnet.com/lang/zhtw/News/Newsltem.aspx?Articleid=31192
(2) Webster R. (1983) Gems: Their Sources, Descriptions and Identification. 4th Ed. Butterworth & Co. England 1006 pp.
(3) Gubelin E.J. (1975) The Color Treasury of Gemstones. English translation. SilvaVerlag, Zurich, pp.138.
(4) http://www.ica-gocolor.com/gem-by-gem/english/sapphire.html
(5) Hughes R.W. (1997) Ruby and Sapphire. RWH Publishing, Boulder, Colorado, 511 pp.
(6) http://www.miilenniumsapphire.com/pages/famousgems.html#historic
(8) Drucker R.B. (1999) Venue and value. The wide-ranging prices of sapphires and emeralds. Jeweler’s Circular Keystone, Vol. 170, No. 3, pp. 174-181.
(9) Mychaluk K.A. (1995) The Yogo sapphire deposit. Gems & Gemology, Vol. 31, No. 1, pp. 28-41.
(10) Smith C.P., McClure S.F., Shigley J.E., Notari F., Giuliani G. Van der Bogert C. (submitted) Corundum – Source Type Classification and Geographic Origin Declarations: Part 1. Gems & Gemology
(11) Smith C.P. (2010) Sapphire Sources of the World. World of Gems Conference I1. GemWorld International, Autumn 2010, pp. 3-9.
(12) Gubelin E.J. (1968) Die Edelsteine der Insel Ceylon. Gibelin, Lucerne, 152 pp.
(13) Themelis T. (2000) Mogok – Valley of Rubies & Sapphires. A&T Publishing, Los Angeles, 270pp.
(14) Loubere S., De Ia (1693) A new historical relation of the Kingdom of Siam. London.
(15) Coldham T. (1985) Sapphires from Australia. Gems & Gemology, Vol. 21, No. 3, pp. 130-146.
(16) Atkinson D., Kothavala R.Z. (1983) Kashmir Sapphire. Gems & Gemology, Vol. 19, No. 2, pp. 64-76.
(17) Schwarz D., Petsch E.J., Kanis J. (1996) Sapphires from the Andranondambo region, Madagascar. Gems & Gemology, Vol. 32, No. 2, pp. 80-99.
(19) Smith C.P., Gi belin E.J., Bassett A.M., Manandhar M.N. (1997) Rubies and fancy-color sapphires from Nepal. Gems & Gemology, Vol. 33, No. 1, pp. 24-41.
(20) Smith C.P., Kammerling R.C., Keller A.S., Peretti A., Scarratt K.V., Khoa N.D., Repetto S. (1995) Sapphires from Southern Vietnam. Gems & Gemology, Vol. 31, No. 3, pp. 168-186.
(21) Pardieu V., Thirangoon K., Lomthong P., Saeseaw S., Thanachakaphad J., Du Toit G. (2010) Sapphires Reportedly from Batakundi/Basil area: A preliminary examination and a comparison with rubies and pink sapphires from other deposits in Central Asia.http://www.gia.edu/research-resources/news-from-research/batakundi_sapphire.pdf
(22) Themelis T. (2010) The Heat Treatment of Ruby and Sapphire. 2nd Ed. Ted Themelis publishing, Bangkok, Thailand, pp. 384.

Additional References for Key to Sapphire Chart: 
Garnier V., Giuliani G., Ohnenstetter D., Schwarz D. (2004a) Les gisements de corindon: Classification et genese. Le Regne Mineral, No. 55, pp. 7-34 plus references.
Giuliani G., Ohnenstetter D., Gamier V., Fallick A.E., Rakotondrazafy M., Schwartz D. (2007) The Geology and Genesis of Gem Corundum Deposits, Chapter 2. Geology of Gem Deposits: Short Course Series, Vol. 37. Ed. Groat L.E., pp. 23-78.
Peucat ,t-J., Ruffault P. Fritsch E., Simonet C., Bouhnik-Le Coz M., Lasnier B. (2005) Un nouvel outil geochimique de renaissance des saphirs bleus basaltiques et metamorphiques: Le rapport Ga/Mg. Revue de Gemmologie a.f.g., No. 153, pp. 8-12.
Schwarz D. (1998) Aus Basalten, Marmoren and Pegmatiten: Spezielle Ursachen formten in der Erdkruste edle Rubine and Saphir. In C. Weise, ed., Rubin, Saphir & Korund; Schon, Hart, Selten, Kostbar, ExtraLapis, Vol. 15, pp. 5-9.
Smith C.P., McClure S.F., Shigley J.E., Notari F., Giuliani G. Van der Bogert C. (submitted) Corundum – Source Type Classification and Geographic Origin Declarations: Part 1. Gems & Gemology
Sutherland F.L., Schwarz D., Jobbins E.A., Coenraads R.R. Webb G. (1998) Distinctive gem corundum suites from discrete basalt fields: a comparative study of Barrington, Australia, and West Pailin, Cambodia, gemfields. Journal of Gemmology, Vol. 6, No. 2, pp. 65-85.


Saturday, September 20, 2014

Clarity




Blue sapphires tend to have more inclusions than most fancy-color sapphires. Gemologists use the term "inclusion" to define characteristics found inside a stone. Inclusions are often used as an indication that the gemstone is of natural origin. A "blemish" is a characteristic that affects the stone's surface. 

Sapphire Inclusions

  • Crystals - solid inclusions of various shapes and sizes. Extremely small crystals are referred to as pinpoints or grains.
  • Silk - fine fibers of titanium dioxide (rutile) or other minerals that resemble the look of silk. Well-formed silk indicates that the sapphire underwent no heat-treatment and is of natural origin. Silk is a preferred inclusions in sapphires.
  • Needles - long, thin inclusions of either crystals, or tubes filled with gas or liquid (growth tubes)
  • Cracks - feather-like inclusions also known as fractures or fissures
  • Parting - breakage along a plane of weakness
  • Twinning - two crystals grown out of one another or next to each other
  • Halos - circular fractures surrounding a crystal
  • Fingerprints - common in sapphire, these inclusions look like human fingerprints
  • Color zoning - uneven color distribution in the sapphire
  • Cavities - holes extending into the sapphire from the surface
  • Chips - broken off pieces along the girdle or on the culet of the sapphire

Sapphire Surface Blemishes

  • Scratches - lines scraped on a gemstone
  • Pits - tiny holes on the stone's surface
  • Nicks - broken parts of a stone's girdle or facet
  • Abrasions - rough scrapings along the stone's facet edges

Clarity Grades

Gem Nation assigns the following clarity grades to its sapphires:
  • VVS - Very, very slightly included - minor inclusions that can be seen under 10x magnification, but invisible to the naked eye. No effect on appearance.
  • VS - Very slightly included - noticeable inclusions sometimes visible to the unaided eye, and very easy to see under 10x magnification. Little to no effect on brilliance.
  • SI1 - Slightly included - large or numerous inclusions that can be easily seen under 10x magnification. These inclusions are apparent/very apparent with the naked eye. Slight effect on appearance, little to no effect on brilliance.
  • SI2 - Slightly included - obvious inclusions that can be easily seen under 10x magnification. Slight effect on appearance and brilliance.
  • I1 - Obvious inclusions - significant effect on appearance, brilliance and transparency
  • I2 - Prominent inclusions - significant effect on appearance, brilliance and transparency
  • I3 - Numerous and prominent inclusions - severe effect on appearance, brilliance and transparency

Transparency


Sapphire transparency ranging
from Transparent to Opaque.
Transparent is ideal.
The degree of visibility through a sapphire is known as its transparency. It is an often-overlooked characteristic when discussing sapphires. Transparency is designated as follows:
  • Transparent - objects look clear and distinct through the stone. These sapphires usually have excellent brilliance despite any inclusions they may have.
  • Semitransparent - objects look slightly hazy or blurry through the stone
  • Translucent - objects are difficult to see through the sapphire. Light can pass through, but it is somewhat diffused.
  • Semi-translucent or semi-opaque - a small fraction of light passes through the stone
  • Opaque - almost no light passes through the stone

Color



Sapphire and the color blue tend to be synonymous. Although many sources claim that its name is of Greek derivation, its roots seem most likely to be from ancient Hebrew - which describes it as a deep blue stone. But sapphires are not just available in the blue variety for which they are named. They are also found in a colorless variety (which looks similar to diamond) and in other colors, called "fancy colors" - shades of orange, yellow, green, purple and pink. Three terms are used to refer to the color of sapphire:

  • Hue refers to the sapphire's basic color - blue, slight green, strong green, slight purple, and strong purple.
  • Saturation (also called color purity and intensity) is the extent to which the hue is masked by brown or gray.
  • Tone refers to the amount of color in the sapphire ranging from very light to very dark.


Blue sapphire Hues ranging
from Slight Green to Strong
Purple. Blue is ideal.


Ruby Saturation showing
color-purity from Vivid to
Weak. Vivid is ideal.


Sapphire Tone ranging from
Very Dark to Very Light.
Medium tone is ideal.
 
Blue sapphire color table combining saturation and tone. The table on the right shows the most desirable color range.

On its own, the word "sapphire" refers only to the blue gemstone variety. The term cornflower blue is often associated with the best quality sapphires. But this term carries with it a perceived difference in color for different people. Most experts agree, however, that medium-to-dark vivid-blue (or violet-blue) sapphires are the best.

The most sought after colors tend to be vivid, pure and highly saturated devoid of hints of brown or gray. You will often see dark black or gray areas in the sapphire, known as extinction. Extinction is affected by the tone, cut, lighting quality and lighting position. Fewer areas of extinction are preferred. Lighter-colored, shallower stones normally show less extinction than darker, deeper-cut stones.

Unlike diamonds that have a 23 letter color-grading system, sapphires lack a convenient method to characterize their color. This is due in large part to the extreme ranges of tone, hue and color purity in sapphires. Judging the ideal color in a sapphire has been largely left up to the eye of the beholder.

Padparadscha sapphires


These extremely rare and prized sapphires are medium-toned orange-pink stones found in Sri Lanka. This beautiful variety of sapphire may be priced at over $20,000 per carat. Gem Nation is pleased to be able to offer these sapphires to its customers. Please contact us for further information.

Pink sapphire


Other than Padparadscha, pink sapphires are the most valuable of the fancy sapphires. Found mostly in Burma or Sri Lanka, these gorgeous gems display a saturated hot pink color. Gem Nation is pleased to be able to offer these sapphires to its customers. Please contact us for further information.

Other sapphire colors also exist (orange, purple, yellow, green and colorless), but they are less popular and are not dealt with here. Gem Nation is pleased to be able to offer a full range of colored and colorless sapphires to its customers. Please contact us for further information.