Kanye's Bling'ed Out Grin

Kanye West shocks fans with the revelation he's permanently replaced his bottom teeth with diamonds.

Rare Pink Diamond Could Net US$38m

A rare pink diamond that goes on sale next month could fetch up to 38million US dollars (£25million) according to auctioneers Sotheby's.

Hope Diamond Put on Display 'Naked'

The world's largest blue diamond went on public display Wednesday, for the first time without its ornate setting. The 45.5-carat, walnut-size diamond will be on view by itself for several months while a new setting is prepared.

Dazzling Diamonds at Christie's

Preview of some of the diamonds and vintage jewellery being sold at Christie's London.

Rare Diamond Sells for Record Amount

A seven carat blue diamond has fetched a record amount at auction. The rare gem was sold for more than eight million dollars. The size of the gem is smaller than a penny.

Rare Blue Diamond For Sale

A stunning jewel could reach 8.5million dollars at auction next month.

Diamond Colours - Colour Grading

A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow hue is detectable, while intense pink or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. Out of all colored diamonds, red diamonds are the rarest of all. The Aurora Diamond Collection displays a spectacular array of naturally colored diamonds, including red color diamonds.

Possible Colours

Diamonds occur in a variety of colors — steel gray, white, blue, yellow, orange, red, green, pink to purple, brown, and black. Colored diamonds contain interstitial impurities or structural defects that cause the coloration, whilst pure diamonds are perfectly transparent and colorless. Diamonds are scientifically classed into two main types and several subtypes, according to the nature of impurities present and how these impurities affect light absorption:

Type I diamond has nitrogen (N) atoms as the main impurity, commonly at a concentration of 0.1 percent. If the N atoms are in pairs they do not affect the diamond's color; these are Type IaA. If the N atoms are in large even-numbered aggregates they impart a yellow to brown tint (Type IaB). About 98 percent of gem diamonds are type Ia, and most of these are a mixture of IaA and IaB material: these diamonds belong to the Cape series, named after the diamond-rich region formerly known as Cape Province in South Africa, whose deposits are largely Type Ia. If the N atoms are dispersed throughout the crystal in isolated sites (not paired or grouped), they give the stone an intense yellow or occasionally brown tint (Type Ib); the rare canary diamonds belong to this type, which represents only 0.1 percent of known natural diamonds. Synthetic diamond containing nitrogen is Type Ib. Type I diamonds absorb in both the infrared and ultraviolet region, from 320 nm. They also have a characteristic fluorescence and visible absorption spectrum (see Optical properties of diamond).

Type II diamonds have no measurable nitrogen impurities. Type II diamonds absorb in a different region of the infrared, and transmit in the ultraviolet below 225 nm, unlike Type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum. Type IIa diamond can be colored pink, red, or brown due to structural anomalies arising through plastic deformation during crystal growth—these diamonds are rare (1.8 percent of gem diamonds), but constitute a large percentage of Australian production. Type IIb diamonds, which account for 0.1 percent of gem diamonds, are usually a steely blue or grey due to scattered boron within the crystal matrix; these diamonds are also semiconductors, unlike other diamond types (see Electrical properties of diamond). However, an overabundance of hydrogen can also impart a blue color; these are not necessarily Type IIb.

Also not restricted to type are green diamonds, whose color is derived from exposure to varying quantities of radiation.

Grading white diamonds

The majority of diamonds that are mined are in a range of pale yellow or brown color that is termed the normal color range. Diamonds that are of intense yellow or brown, or any other color are called fancy color diamonds. Diamonds that are of the very highest purity are totally colorless, and appear a bright white. The degree to which diamonds exhibit body color is one of the four value factors by which diamonds are assessed.

History of color grading

Color grading of diamonds was performed as a step of sorting rough diamonds for sale by the London Diamond Syndicate.

As the diamond trade developed, early diamond grades were introduced by various parties in the diamond trade. Without any co-operative development these early grading systems lacked standard nomenclature, and consistency. Some early grading scales were; I, II, III; A, AA, AAA; A, B, C. Numerous terms developed to describe diamonds of particular colors: golconda, river, jagers, cape, blue white, fine white, and gem blue, "brown".

Grading the normal color range

Refers to a grading scale for diamonds in the normal color range used by internationally recognized laboratories (GIA & IGI for example). The scale ranges from D which is totally colorless to Z which is a pale yellow or brown color. Brown diamonds darker than K color are usually described using their letter grade, and a descriptive phrase, for example M Faint Brown. Diamonds with more depth of color than Z color fall into the fancy color diamond range.

Diamond color is graded by comparing a sample stone to a masterstone set of diamonds. Each masterstone is known to exhibit the very least amount of body color that a diamond in that color grade may exhibit. When sample stones are compared with the master stone, the grader assesses whether the sample has more, less or equal color to the masterstones. A grading laboratory will possess a complete set of masterstones representing every color grade. However, the independent grader working in a retail will possess a range of masterstones that covers only the typical grade range of color they expect to encounter while grading. A typical grading set of masterstones would consist of five diamonds in two grade increments, such as an E, G, I, K, and M. It is not common for a grader to possess a D masterstone, as the E masterstone is more useful in dividing the D and E color grades. The intermediate grades are assessed by the graders judgement.

Diamonds in the normal color range are graded loose, with the table facet facing downward and pavilion side upwards. When color grading is done in the mounting, other techniques will apply and the grade will usually be expressed as a range (for example F-G)

Published under the GNU Free Documentation License

Diamonds - Clarity - Grading Scales

Diamond clarity is a quality of diamonds relating to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects called blemishes.

Clarity is one of the four Cs of diamond grading, the others being carat, color, and cut. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. A clarity grade is assigned based on the overall appearance of the stone under 10x magnification.

Most inclusions present in gem-quality diamonds do not affect the diamonds' performance or structural integrity. However, large clouds can affect a diamond's ability to transmit and scatter light. Large cracks close to or breaking the surface may reduce a diamond's resistance to fracture.

Diamonds with higher clarity grades are more valued, with the exceedingly rare "flawless" graded diamond fetching the highest price. Minor inclusions or blemishes are useful, as they can be used as unique identifying marks analogous to fingerprints. In addition, as synthetic diamond technology improves and distinguishing between natural and synthetic diamonds becomes more difficult, inclusions or blemishes can be used as proof of natural origin.

Diamond Flaws
See our previous article: Diamonds - Flaws External  & Internal

Clarity grading

Gemological Institute of America (GIA)

History

In 1952, Richard T Liddicoat, along with Lester Bensen, Joe Phillips, Robert Crowningshield and Bert Krashes began to work on a new diamond grading system which they called the diamond grading and evaluation appraisal.

In 1953, they released their new system which assessed three aspects of diamonds; make, color and clarity.

They took terminology used in the industry at the time and refined the definitions to produce a clarity scale by which diamonds could consistently be graded. The system at that time contained nine grades, flawless, VVS₁, VVS₂, VS₁, VS₂, SI₁, SI₂, I₁, and I₂. The I of the I₁, and I₂ grades stood for imperfect.

During the 1970s two changes were made to the system. Firstly, the internally flawless grade was added, as GIA noticed that many diamonds were being aggressively cut to remove any surface blemishes, and thereby reducing the cutting quality (make) of the diamonds. The internally flawless grade gave diamond manufacturers a choice to leave blemishes on the surface of the stone, and achieve a grade higher than VVS₁. The second change made to the grading system, was the introduction of the I₃ grade. This change was made in response to a growing number of diamonds of very low clarity being cut.

The last change to the clarity grading system took place in the 1990s when the term imperfect was changed to included.

The GIA grading system today

The GIA diamond grading scale is divided into six categories and eleven grades. The clarity categories and grades are:

• Flawless category (FL) diamonds have no inclusions or blemishes visible under 10x magnification.
• Internally Flawless category (IF) diamonds have no inclusions visible under 10x magnification, only small blemishes on the diamond surface
• Very, Very Slightly Included category (VVS) diamonds have minute inclusions that are difficult for a skilled grader to see under 10x magnification. The VVS category is divided into two grades; VVS1 denotes a higher clarity grade than VVS2. Pinpoints and needles set the grade at VVS
• Very Slightly Included category (VS) diamonds have minor inclusions that are difficult to somewhat easy for a trained grader to see when viewed under 10x magnification. The VS category is divided into two grades; VS1 denotes a higher clarity grade than VS2. Typically the inclusions in VS diamonds are invisible without magnification, however infrequently some VS2 inclusions may still be visible to the eye. An example would be on a large emerald cut diamond which has a small inclusion under the corner of the table.
• Slightly Included category (SI) diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification. The SI category is divided into two grades; SI1 denotes a higher clarity grade than SI2. These may or may not be noticeable to the naked eye.
• Included category (I) diamonds have obvious inclusions that are clearly visible to a trained grader under 10x magnification. Included diamonds have inclusions that are usually visible without magnification or have inclusions that threaten the durability of the stone. The I category is divided into three grades; I1 denotes a higher clarity grade than I2, which in turn is higher than I3. Inclusions in I1 diamonds often are seen to the unaided eye. I2 inclusions are easily seen, while I3 diamonds have large and extremely easy to see inclusions that typically impact the brilliance of the diamond, as well as having inclusions that are often likely to threaten the structure of the diamond.

GIA clarity grading procedure

GIA clarity grading is performed under 10x magnification with darkfield illumination. The GIA Gem Trade Laboratory uses as standard equipment binocular stereo microscopes which are able to zoom to higher magnifications. These microscopes are equipped with darkfield illumination, as well as an ultraviolet light filtered overhead light. When grading is performed using a 10x handheld loupe, 'darkfield' illumination is more difficult to achieve. The grader must use a light source in such a way that the base of the stone is lit from the side, and the crown of the stone is shielded from the light.

After thoroughly cleaning the diamond, the diamond is picked up using tweezers in a girdle-to-girdle hold. The grader views the diamond for the first time through the table, studying the culet area of the stone for inclusions. The diamond is then set down, and picked up with the tweezers in a table-to-culet hold. In this position the diamond can be studied from the pavilion side, and the crown side, examining the diamond through each facet for inclusions. Once a sector of the diamond has been thoroughly examined the grader rotates the diamond in the tweezer, so that the neighboring sector can be examined. The grader uses darkfield lighting to reveal characteristics, and alternates to reflected, overhead lighting to ascertain whether a characteristic lies within the stone, on the stones surface, or both. If the grader is using a stereo microscope, they may zoom in to a higher magnification to make closer observations of an inclusion, but then return to 10x magnification to make an assessment of its impact on the clarity grade.

If a stereo binocular microscope has been used, a final assessment using a 10x loupe is performed before the final judgment is made on the clarity of the stone. The grader first decides the clarity category of the diamond using one of the keywords none (FL, or IF if blemished), minute (VVS), minor (VS), noticeable (SI), or obvious (I). The decision is then made on the grade of the diamond.

Grading systems by other organizations

The clarity grading system developed by the GIA has been used throughout the industry as well as by other diamond grading agencies including the American Gemological Society (AGS), European Gemological Laboratory (EGL), and the International Gemological Laboratory (IGL). These grading agencies base their clarity grades on the characteristics of inclusions visible to a trained professional when a diamond is viewed from above under 10x magnification.

Confédération Internationale de la Bijouterie, Joaillerie, Orfèvrerie des Diamants, Perles et Pierres (CIBJO)

The CIBJO or the International Confederation of Jewellery, Silverware, Diamonds and Stones developed the International Clarity Scale for grading diamonds. This clarity scale mirrors the GIA grading scale, except nomenclature varies. The CIBJO system names these clarity grades; Loupe Clean, Very, very small inclusions (VVS1 and VVS2), Very small inclusions (VS1 and VS2), Small inclusions (SI1 and SI2), Pique (P1, P2, and P3).

Clarity grading by CIBJO standards is by examination using a 10x achromatic, aplanatic loupe in normal light.

American Gem Society

The American Gem Society grades clarity on a number scale between 0 and 10. These numbers grades correlate almost exactly with the GIA system, but with some differences. The flawless and internally flawless (0) grades are grouped together with notation defining whether the stone is free from external blemishes, the VVS through SI grades are numbered 1 through 6, and then there are four grades 7 through 10 for the included category.

Clarity grading by AGS standards requires examination using a binocular stereo microscope equipped with adjustable zoom magnification and darkfield illumination.

International Diamond Council (IDC)

The IDC or the International Diamond Council uses a very similar standard to CIBJO. IDC loupe clean stones that have external blemishes have notations made on the grading report. IDC clarity grading is by examination using a 10x achromatic, aplanatic loupe in normal light.

European Gemological Laboratory

The European Gemological Laboratory (EGL) introduced the SI3 as a clarity grade. While intended as a range to include borderline SI2 / I1 stones, it is now commonly used to mean I1's which are "eye clean", that is, which have inclusions which are not obviously visible to the naked eye.

Clarity grading considerations

All grades reflect the appearance to an experienced grader when viewed from above at 10x magnification, though higher magnifications and viewing from other angles are used during the grading process. The grader studies the diamond for internal characteristics, and judges them on the basis of five clarity factors; size, number, position, nature, and color or relief. The clarity grade is assessed on the basis of the most noticeable inclusions, otherwise called: grade setting inclusions. This means that less significant inclusions are ignored for the purposes of setting the grade. However, they may still be plotted onto a diamond plot chart.

Accurate clarity grading as with other grading steps must be done with the diamond loose; meaning not set into any mounting. Inclusions are often difficult to see from the crown side of the diamond, and may be concealed by the setting.

Size

The first clarity factor which is assessed is a clarity characteristic's size. Larger characteristics are typically more noticeable under magnification, thereby placing the diamond into a lower clarity grade.

Number

The second clarity factor which is assessed is the number of clarity characteristics. Generally the more characteristics the lower the clarity grade. This assessment is made by judging how readily they can be seen, not by the actual number of characteristics.

Position

The third clarity factor which is assessed is the characteristic's position. When an inclusion is directly under the table of the diamond it is most visible. An inclusion under the table and positioned close to a pavilion facet, will reflect multiple times around the stone, giving this type of inclusion the name reflector. Reflectors are graded as if each reflection were an inclusion (although in plotting the diamond it is only plotted once). For this reason reflectors have a greater impact on the clarity grade. Inclusions become less visible when they are positioned under the crown facets, or near the girdle of the stone. These inclusions may often be more easily seen from the pavilion side of the diamond than from crown side of the diamond.

In addition the position of large feathers, knots and included crystals positioned where they extend to the girdle or crown of the stone, affect the clarity grade. Diamonds worn in jewelry typically will withstand breakage, however inclusions of this nature, in these positions, can pose a risk for further extension of the break in the structure of the diamond. Inclusions that are judged to pose at least a moderate risk of breakage to the stone are graded in the included category.

Nature

The fourth clarity factor which is assessed is a characteristic's nature. The characteristic's nature determines whether it is internal where they extend into the stone, or external; where they are limited to the surface of the stone. Internal characteristics automatically exclude the diamond from the flawless, and internally flawless categories. External characteristics exclude the diamond from the flawless category.

A diamond's internal characteristics can be a; bruise, cavity, chip, cleavage, cloud, crystal, feather, grain center, indented natural, internal graining, knot, laser drill hole, needle, pinpoint, or twinning wisp.

A diamond's external characteristics can be an; abrasion, natural, nick, pit, polish lines, polish mark, scratch, surface graining, or extra facet.

The nature will also detail whether an inclusion poses a risk to the stone. Inclusions that cause or may cause a break in the crystal structure (included crystal, feather, knot, cleavage) are considered alongside their position, to assess whether they pose a moderate level of risk for further breakage.

Color or relief

The fifth clarity factor which is assessed is the color and relief of clarity characteristics. Characteristics that contrast with the surrounding diamond are said to have relief. The degree to which this color and relief is noticeable affects the clarity grade of the diamond. Colored inclusions invariably show contrast and are more easily seen. An exception is a black pinpoint inclusion which is often more difficult to see than a white pinpoint.

Rarity and value

Diamonds become increasingly rare when considering higher clarity gradings. Only about 20 percent of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone; the other 80 percent are relegated to industrial use. Of that top 20 percent, a significant portion contains an inclusion or inclusions that are visible to the naked eye upon close inspection. Those that do not have a visible inclusion are known as "eye-clean" and are preferred by most buyers, although visible inclusions can sometimes be hidden under the setting in a piece of jewelry. The most expensive gem diamonds fall within the VS and SI grades with FL, IF, and even VVS stones commanding significant premiums, while I stones are shunned by most buyers. FL and IF stones are sometimes referred to as "museum quality" or "investment grade" to denote their rarity, although the term "investment grade" is misleading as diamonds have historically been illiquid and questionable stores of value.

Clarity enhancement

Laser "drilling" involves using a laser to burn a hole to a colored inclusion, followed by acid washing to remove the coloring agent. The clarity grade is the grade after the treatment. The treatment is considered permanent.

GIA, as a matter of policy, does NOT certify clarity-enhanced diamonds. If you see a GIA Diamond Report with the words "clarity enhanced" or "fracture-filled," it is surely a counterfeit report.

Clarity can also be "enhanced" by filling the fracture much like a car windshield crack can be treated. Such diamonds are sometimes called "fracture filled diamonds". Reputable vendors must disclose this filling and reputable filling companies use filling agents which show a flash of color, commonly orange or pink, when viewed closely. There is a significant price discount for fracture-filled diamonds. The GIA will not grade fracture-filled diamonds, in part because the treatment isn't as permanent as the diamond itself. Reputable companies often provide for repeat treatments if heat causes damage to the filling. The heat required to cause damage is that of a blowtorch used to work on settings, and it is essential to inform anyone working on a setting if the diamond is fracture-filled, so they can apply cooling agents to the diamond and use greater care while working on it.

Published under the GNU Free Documentation License

Diamonds - Flaws External & Internal

Diamonds flaws are common and most diamonds are not perfect and most of them consist of some inclusion or imperfections. These inclusions are also known as flaws and exist in various forms, exterior and interior.
Inclusions are also classified in the manner in which they were formed. For example, syngenetic diamond inclusions are those inclusions which were formed while a diamond was being made. On the other hand, epigenetic inclusions were formed after a diamond was made.

External flaws

The most common impurity in diamond is nitrogen, which can comprise up to 1% of a diamond by mass. Nitrogen as a diamond impurity was first identified in 1959 by Kaiser and Bond of Bell Telephone.

Blemishes

These diamond flaws are present on the surface of a stone and can occur naturally. However, these are more likely to be caused due to the external environment, when a diamond was being cut and polished.

Scratches

These are fine lines found on the surface of the diamond. They may have been present naturally or caused when a diamond was cut. While minor scratches can be removed through proper polishing, deep scratches are can rarely be removed by treating the diamond.

Extra facets

These are usually cut to remove blemishes or certain close to surface inclusions on diamonds. At times these extra facets are also cut to enhance the brilliance of the diamond. These do not usually affect the clarity grade of a diamond.

Fracture

A breakage in diamonds that is not parallel to the cleavage plane is referred to as a fracture. Fractures are usually irregular in shape making a diamond look chipped. The practice of fracture filling is commonly employed to improve the diamond clarity of such diamonds.

Fingerprints

Fingerprint inclusions in the shape of fingerprints can sometimes be found in diamonds. However such inclusions are rare in diamonds as compared to other stones like rubies. Such inclusions are usually formed during fluid assisted partial healing of fractures already present in stones. For this to take place in diamonds, high temperatures and pressure (HTHP) are required, which is unusual. Till now few such inclusions have been reported in natural blue and colorless diamonds. While this could indicate that diamonds have been HTHP treated, giving the required temperatures for fingerprint inclusions, such is not always the case. The earth may also cause geologically high temperatures, leading to the formation of fingerprint inclusions.

Pits

Small holes may be present on the surface of a diamond. These pits are usually not visible to the naked eye. However, pits present on the table facet of a diamond are usually visible and reduce the clarity of a diamond.

Nicks

Diamonds are also chipped at places causing the appearance of nicks. This is often repaired by adding extra facets. However too many facets reduce the brilliance of a diamond and are to be avoided.

Naturals

This refers to the original surface of the diamond which has not been polished and left as it is. Naturals are usually left on or near the girdle of the diamond. While these are considered as blemishes, the presence of naturals is a sign of good cutting practice, where the cutter has managed to retain as much of the original weight as possible. Indented naturals are also seen to exist on some stones, where the portion of the natural is seen to dip inside slightly from the diameter of the stone. Here the cutter usually leaves the indented natural either at the girdle or pavilion of the stone, in order to keep it less noticeable. In such positions, the natural is not visible even with a loupe. Indents can be removed if the cutter polishes out rougher. However, this would result in a drop of the diamond's weight by up to 25%.

Carbons

Diamonds are made from carbon, usually graphite. Nevertheless, while a diamond is being formed, it may not totally crystallize leading to the presence of small dots of black carbon. These black spots have been classified to be those of graphite, pyrrhotite and pentlandite. These surface flaws resemble a small black dot and may affect the clarity of the stone depending on the size of imperfection. The occurrence of this kind of flaw is rare in diamonds as compared to pinpoint inclusions. Carbons are usually seen in white or blue-white stones. However carbons are not commonly found in diamonds of poorer colors.

Chips

The breaking off of a small piece of diamond towards the surface is usually referred to as chipping. The term may be confused with 'diamond chips' which refer to very small pieces of diamonds. These are usually caused due to minor impact from the environment. Downward impact caused when a stone is being set or is being worn, can cause chips on the culet of the diamond. As these are commonly caused when a diamond is worn, it is suggested that while diamonds are being set, a little space be left between the base of the diamond and the head of the prongs of the ring. This space acts as a cushion protecting the diamond from possible chipping when it falls. However, Chips are easy to remove by treating the diamond.

Cavity

Larger chipping in diamonds leads to a diamond cavity. This term thus refers to the presence of a large or deep opening in a diamond. These can be caused when a diamond cutter has removed a large crystal inclusion close to the diamond surface.

Internal flaws

Every natural diamond crystal contains typical intrinsic or self-defects: vacancies, dislocations, and interstitial atoms.

Crystal/mineral inclusions

Some diamonds show the presence of small crystals, minerals or other diamonds. These are classified in various categories depending upon the size and structure of the inclusion. While many such inclusions are small in size and not visible to the naked eye, some diamonds may have large inclusions, which can be seen with the naked eye and can affect a diamond's clarity and also its life. Some crystals resemble a diamond inside a diamond and may also add to the look of the stone. These take on shapes of bubbles, needles or grains and are classified as under.

Pinpoint inclusions

As the name implies, these inclusions are minute crystals usually white in color present inside the diamond. These resemble a small point of light and are, by far, the most common of all flaws found in diamonds. Most pinpoint inclusions do not affect the clarity of a diamond and are not visible to the naked eye and are usually not indicated on the plotting diagrams of diamond reports. Comments such as pinpoints not shown may be listed in the comments section.

Needles

Diamond crystals in a diamond can also be present in the form of long and thin needles. These may not be visible to the naked eye, unless the needle inclusion is of a noticeable color or has a noticeable presence. Some needle inclusions are known to give diamonds a special look too.

Cloud

The presence of three or more pinpoint inclusions close together can create an area of haze or a cloud in the diamond. While the occurrence of a small cloud is not visible to the naked eye, presence of many pinpoints covering a large area can affect the clarity of the diamond. These are usually indicated on grading reports in the form of tiny red dots close together or as circles and other formations.

Knots

When diamond crystals extend to the surface of the diamond, they are referred to as knots. These can be viewed under proper lighting conditions with a diamond loupe. Certain knot formations may also cause raised areas on particular facets of the diamond. The presence of knots may affect both the clarity and durability of the diamond and are best avoided.

Grain lines

Crystal inclusions in diamonds can also occur in the form of lines, known as grain lines. These are usually formed due to improper crystallization of the diamond, when it was being formed. Grain lines can also be caused due to improper polishing of the diamond. Even skilled diamond cutters may come across diamonds with variations in hardness when a facet is polished. This can cause microscopic lines across the facet. These grains are usually difficult to remove without excessive weight loss. Grain lines are commonly seen in pink fancy diamonds. A saturation of grain lines on pink stones can also make them look red.

Feathers

These are cracks in the stone that resemble the design of feathers. Presence of this in a diamond usually does not affect the life of the stone unless and until the feather runs through a major length of the stone or shows major stress points where it can break. If the cracks reach the surface or have deep fissures, the durability of the stone may be reduced with the possibility of the stone breaking with age.

Intergrowths

Twinning wisps or intergrowths may also be seen in diamonds. These formations are usually inclusions in diamonds that have twisted together during the time of diamond formation. Thus various inclusions like pinpoints, needles or feathers may form together creating a white strip inside the diamond. Surface graining may also be seen in some cases. Such intergrowths are more commonly seen in fancy shaped diamonds and are extremely rare in ideal cut diamonds.

Cleavage

These are cracks in a diamond that occur in a straight line and are parallel to one of the diamond's crystallographic planes. Cleavages are usually caused by deep internal strain in a diamond and could also have been caused by a strong blow on the diamond. It usually shows no feathers and has a great chance of causing the stone to split, especially if placed in the high pressure grip of prongs in rings. Stones with cleavage must be chosen carefully and avoided as far as possible.

Bearding

Also known as girdle fencing or 'dig marks', this is caused around the diamond's girdle as the diamond is cut or bruited. These fine lines usually resemble a hair strand and do not present a problem. However extensive bearding can lessen the brightness of the diamond. It is suitable that such diamonds be cut or polished again to improve luster.

Diamond flaws are not always a negative phrase. In fact it is these flaws that often lend a diamond its distinctive beauty. It is often these flaws that make a stone unique.

Published under the GNU Free Documentation License

Diamonds - Carat Weight - Rapaport Prices - TCW

Diamonds

Carat Weight
The carat weight measures the mass of a diamond. One carat is defined as 200 milligrams (about 0.007 ounce avoirdupois). The point unit—equal to one one-hundredth of a carat (0.01 carat, or 2 mg)—is commonly used for diamonds of less than one carat. All else being equal, the price per carat increases with carat weight, since larger diamonds are both rarer and more desirable for use as gemstones.


Price
The price per carat does not increase smoothly with increasing size. Instead, there are sharp jumps around milestone carat weights, as demand is much higher for diamonds weighing just more than a milestone than for those weighing just less. As an example, a 0.95 carat diamond may have a significantly lower price per carat than a comparable 1.05 carat diamond, because of differences in demand.


Rapaport Diamond Report
A weekly diamond price list, the Rapaport Diamond Report is published by Martin Rapaport, CEO of Rapaport Group of New York, for different diamond cuts, clarity and weights. It is currently considered the de-facto retail price baseline. Jewelers often trade diamonds at negotiated discounts off the Rapaport price (e.g., "R -3%").

Wholesale
In the wholesale trade of gem diamonds, carat is often used in denominating lots of diamonds for sale. For example, a buyer may place an order for 100 carats of 0.5 carat, D–F, VS2-SI1, excellent cut diamonds, indicating he wishes to purchase 200 diamonds (100 carats total mass) of those approximate characteristics. Because of this, diamond prices (particularly among wholesalers and other industry professionals) are often quoted per carat, rather than per stone.

TCW
Total carat weight (t.c.w.) is a phrase used to describe the total mass of diamonds or other gemstone in a piece of jewelry, when more than one gemstone is used. Diamond solitaire earrings, for example, are usually quoted in t.c.w. when placed for sale, indicating the mass of the diamonds in both earrings and not each individual diamond. T.c.w. is also widely used for diamond necklaces, bracelets and other similar jewelry pieces.

Published under the GNU Free Documentation License

Diamonds - Mineralogy - Mining - Name - Popularity - Distribution

Diamond is the allotrope of carbon where the carbon atoms are arranged in an isometric-hexoctahedral crystal lattice.

Hardness
A diamond's hardness and high dispersion of light make it useful for industrial applications and jewelry.
It is the hardest known naturally-occurring mineral.
It is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds (known as Type-II diamonds) that are harder than the diamonds used in hardness gauges.
Presently, only aggregated diamond nanorods, a material created using ultrahard fullerite (C₆₀) is confirmed to be harder, although other substances such as cubic boron nitride, rhenium diboride and ultrahard fullerite itself are comparable.

Diamonds are specifically renowned as a material with superlative physical qualities; they make excellent abrasives because they can be scratched only by other diamonds, borazon, ultrahard fullerite, rhenium diboride, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain their lustre.

Mining
Approximately 130 million carats (26,000 kg (57,000 lb)) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg (220,000 lb) are synthesized annually.

Name
The name diamond derives from the ancient Greek ἀδάμας (adamas) "invincible", "untamed", from ἀ- (a-), "un-" + δαμάω (damáō), "to overpower, to tame". They have been treasured as gemstones since their use as religious icons in ancient India and usage in engraving tools also dates to early human history.

Popularity
Popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns. They are commonly judged by the “four Cs”: carat, clarity, color, and cut.

Distribution
Roughly 49% of diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia. They are mined from kimberlite and lamproite volcanic pipes, which can bring diamond crystals, originating from deep within the Earth where high pressures and temperatures enable them to form, to the surface. The mining and distribution of natural diamonds are subjects of frequent controversy such as with concerns over the sale of conflict diamonds (aka blood diamonds) by African paramilitary groups.

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