What are diamonds ?

Natural diamonds are pure carbon, formed into crystals deep below the earth’s crust many millions of years ago. Diamonds are found and mined in several parts of the world but predominantly in southern Africa where flows of volcanic lava, known as Kimberlite, have carried diamond deposits to the surface. These deposits can be mined or quarried to recover the diamonds within the Kimberlite. As the hardest natural substance known to man, diamonds brought to the surface in this way have survived the effects of geological erosion, often being washed down river valleys and into the sea. Diamonds can therefore be recovered from the alluvial deposits in rivers as well as from the sea bed and even from beaches. In their recovered or “rough” form they are far from the cut and polished gemstones which we prize today. Rough diamonds have to be sorted and graded before those which can be used for jewellery are shipped to specialist cutting and polishing centres around the world. Diamonds not suitable for jewellery are used for industrial cutting and drilling.

Diamond Color

The Diamond Color Scale
The color scale runs the alphabet from D - colorless to Z - light yellow, brown, or gray color. D is the rarest color and thus the most valuable.
Diamonds most often form in nature with nitrogen impurities in their atomic structure.
This causes them to show a subtle tint of yellow color. As you move down the color scale the diamonds become more yellow (or brown or gray) and thus less valuable.
D-E-F Group: Colorless
This diamond group is the rarest and most expensive. They are common enough to be found in many stores, but still command the highest prices. They show virtually no color.
G-H-I Group: Near Colorless
This is a very popular color group because of its lower price, yet they still possess high enough color to face up reasonably white in a mounting. Diamonds in the lower end of this group show a very light shade of color and may present themselves better in a yellow gold setting, rather than in white or platinum.
J-K-L-M: Faint Yellow
This is the group that begins to show slight yellow color.Slight color may be noticeable from the top of the stone, but probably more from the sides.
N through R: Very light Yellow
Diamonds in the N-R group show yellow color even when mounted in jewelry. Determining the exact color of a diamond in this group is less important due to the fact that their prices are similar. Certificates for diamonds in the N-R group are less common because of their relatively low price.
S through Z: Light yellow
Diamonds in this group show substantial color when loose or mounted.
Fancy Colored Diamonds
Fancy Yellow diamonds can command prices as high as D colors or more. Colors below the Z range are considered to have color as an asset and are graded into the fancy color range. The fancy color ranges are as follows: Fancy Light - Fancy - Fancy Intense - Fancy Deep - and Fancy Vivid. While Fancy Yellow is more common, Fancy Colored Diamonds can and do occur in every possible color. Often the color is described with a secondary mixed color preceding it.
Ex: Fancy Intense Orangy-Yellow, with yellow, the second color mentioned, being the predominant color.
So, to summarize, there are Colorless Diamonds (D, E, F), Near Colorless Diamonds (G,H,I), progressively off colored diamonds (J-Z), being yellow, brown, or gray, and Fancy Colored Diamonds. Fancy Colored Diamonds are not always "Natural". Their color may have been modified or enhanced through one or more processes involving irradiation and/or extreme heat. While this enhancement may in fact be permanent, the occurrence of natural color in diamond is far more rare and thus more expensive. The tests for identification of "origin of color" are usually conclusive, but may require sophisticated equipment and extremely qualified testers. It is highly recommended to have the G.I.A. confirm the origin of color, as natural, in any fancy colored diamond of enough size to warrant it.

The Brown Color Group

Brown diamonds have a tint of brownish body color. The brown group is usually less expensive than any other group due to the fact that they are less appealing to most consumers. In their lightest tones, they face up reasonably white in a yellow setting. These stones are often described as "TLB" or Top Light Brown. The brown group is graded by tone, from light to dark in much the same way as other diamonds, however their appearance may be slightly whiter than a diamond of slightly yellowish body color, in the same color grade range. Establishing the correct value with regard to significantly brown diamonds is difficult. The Argyle mines in Australia produce a significant quantity of brown diamonds, and have successfully marketed them using the descriptive names, "cognac" and "champagne".
The common shades are:
Very light brown (champagne), medium brown (champagne), Brown (dark champagne), and Dark brown (fancy cognac). A color scale has been devised by the Argyle Mines of Australia for use in grading these diamonds using C1 - C7 grades to separate them into their progressively darker tonal ranges.

In spite of the significant marketing efforts of the Argyle Mines, demand for the brown diamonds is not great and they generally command relatively low prices.

Fluorescence

Fluorescence is a phenomenon which causes some diamonds to glow under ultra violet light (UV), which is abundant in natural daylight and some artificial lighting.
The following are the possible grades given to fluorescence:
Faint, Medium, Strong, Very Strong
All grading reports denote the diamond’s fluorescence as well as color. It is estimated that 20%-25% of all diamonds have some degree of fluorescence. Most often diamonds will fluoresce blue, but occasionally yellow or green or an unusual color may occur.
Strong fluorescence can cause a diamond to look hazy or less transparent, however this is not always the case. Years ago the term "blue white" was used to describe the finest of diamonds, many of which had bluish overtones caused by fluorescence. Unfortunately the term became misused and seldom accompanied a diamond that was truly white or blue. It is not appropriate to use the expression in modern times unless the diamond truly possesses a bluish hue.
Generally speaking, a diamond with strong fluorescence, sometimes called an over-blue, which diminishes it's brilliance and gives it a sleepy, or greasy appearance, will cost less than one with faint or no fluorescence. If a diamond is lightly tinted and has faint to moderate fluorescence, it may face up whiter than another diamond of similar lightly tinted color possessing no fluorescence, and may actually cost more.

Diamond Clarity

This chart represents the plotting of clarity characteristics as they may appear on a Grading Report from an Independent Lab, such as the Gemological Institute of America, the Jewelry Industry's foremost leader in Education and Evaluation of diamonds and colored stones. Generally, internal characteristics are plotted in red and external (surface) characteristics in green. The plotting is generally "exaggerated" in size to reflect the "nature" of the characteristics, and not the relative size. Even inclusions which are difficult to see under 10x magnification may appear quite large on the plot, in order to accurately describe the type of characteristic to anyone viewing the stone and the report. Please be warned, the enlarged chart is very large and may take a while to open with a slow modem.

IF - INTERNALLY FLAWLESS - describes diamonds which have no internal characteristics observable under 10x magnification, the same conditions as (FL), but which have minor surface blemishes that do not penetrate the stone. These stones are potentially flawless if they underwent additional finishing.
VVS1 & VVS2 - VERY, VERY SLIGHTLY INCLUDED - describes diamonds that have very, very small inclusions which are difficult for a gemologist to see at 10x magnification.
VS1 & VS2 - VERY SLIGHTLY INCLUDED - describes diamonds with very small inclusions which can be difficult to observe with 10x magnification. Inclusions are not visible to the unaided eye, except on larger stones or occasionally with Emerald Cut diamonds.
SI1 & SI2 - SLIGHTLY INCLUDED - describes diamonds with small inclusions which are usually obvious when viewed with 10x magnification. Inclusions are difficult to see with the unaided eye, except on larger stones or occasionally with Emerald Cut diamonds. Generally SI1 graded stones are eye clean, while SI2 graded stones may or may not be eye clean.
I1, I2, & I3 - IMPERFECT - describes diamonds with medium to large inclusions (Piques) which are usually obvious to a gemologist with the unaided eye. An I1 may have an inclusion located to the side while an I2 will have it centrally located or numerous inclusions.

Diamond Cut

The various parts of a diamond are illustrated to the right and below.

The typical faceting style and facet names for the Round Brilliant Cut are illustrated here. Counting the culet, which is not always actually polished as a facet, the Round Brilliant has 58 facets. Their exact placement relative to one another, as well as the proper angles of their placement, plays a critical role in the appearance of the finished stone.
Any diamond which is not "poorly cut" will reflect some of the light which enters it and disperse some of it, which gives diamonds their unique brilliance and dispersion. The primary reason for grinding and polishing facets on a diamond is to enable the light to enter the stone and reflect back to the viewer in a positive way, thus making the given stone "marketable". Unfortunately, economics plays a role in the decision making which directs the size and placement of the facets as well as the ultimate size and shape of the finished stone.

Ideal Cut

Many years ago, the "ideal" proportions of a round brilliant cut were mathematically computed. While these proportions will generate a diamond with not only the maximum reflection of light, they also render the ideal balance of brilliance (reflected white light) and dispersion (refracted spectral colors). Unfortunately, the maximum potential weight recovery from the rough is sacrificed. Modern day diamond cutters attempt to balance these factors and will most frequently allow popular weight categories that are targeted as well as increased yield to direct their cutting decisions.

A diamond which has been cut too shallow will not only reflect less light, but the lessening of the angles of the pavilion facets will also make the stone "window" or show a see through effect. This appears to the eye as if there were dead space instead of sparkle. These diamonds will also often show an internal reflection of the top of the stone in the bottom, which resembles a dark circle or "fish-eye".

A diamond that has been cut too deep will generally appear dark through the center. This occurs because the light is "leaking" through the back of the stone instead of reflecting back to the eye through the top. Add to this, the fact that the diameter of the stone, or it's apparent size, is minimized and you have a smaller facing stone than it's weight would usually render.

The Ideal Cut, which is illustrated below requires exact placement of facets at exact angles relative to one another. They are generally available to a discerning buyer at a premium over all other diamonds in their class.

A Premium Cut diamond demonstrates subtle variations from the Ideal Cut. Although these differences do affect the reflection of light, a Premium Cut still achieves a harmonious balance between it's proportions and the display of brilliance and dispersion.

MM to Carats Stone Conversion

Platinum is Rare.

Ten tons of ore must be mined to produce a single ounce of platinum. It takes five months to process platinum ore into pure platinum. Only after this time can skilled hands work their creativity and craftsmanship, transforming platinum into pieces of wearable art.

Platinum is Pure.

In America, platinum jewelry contains either 90% or 95% pure platinum. By comparison, 18 karat gold is 75% pure and 14 karat is 58% pure gold. Platinum will never tarnish or lose its rich white luster.

Platinum is Strong.

It is the heaviest of the precious metals, weighing almost twice as much as karat gold. Its strength ideally secures diamonds and other precious gems.
Even after many years, platinum will not wear away or wear down. For example, after many years of wear, a gold wedding band's shank will wear down and become thinner. This is not the case with platinum.
As with all precious metals (gold, silver, etc.), platinum can be scratched. However, with platinum, there is actually no material lost from the scratch as there is with gold. If your platinum jewelry becomes scratched, simply take it to your jeweler for a quick polish.

The Strengths of Platinum

Beneath its subtle beauty and understated elegance lie the properties which make platinum truly unique.

Platinum Group metals (Pt, Ir, Pd, Ru, Rh, Os)

Group of precious metals (platinum, iridium, palladium, ruthenium, rhodium, and osmium) that share similar chemical and metallurgical properties.
Most "platinum" used in jewelry is composed of 90% platinum and 10% iridium, which makes it much harder than pure platinum. 5% ruthenium serves same purpose.
Much like gold, platinum purity and alloys are commonly stamped, in abbreviated fashion, on items. Unlike gold, in the U.S., purity is given relative to 1000 parts (per mil), e.g. "950Plat" is 95% pureplatinum.
Palladium and small amount of ruthenium is used in setting heads for platinum jewelry; lighter, less expensive.
Rhodium is used as a plating metal. It gives white gold and platinum a hard, bright finish and slows tarnish on stainless steel.
Platinum has a specific gravity of 21.45.

Silver (Ag)

Pure silver has a specific gravity of 10.5
"Fine Silver" is 99.9% Ag
"Britannia Silver" is 95.84% Ag
"Mexican Silver" is 95% Ag + 5% Cu
"Sterling Silver" is at least 92.5% Ag; harder than pure Ag.
U.S. "Coin Silver" is 90% Ag
Vermeil (Vur-MAY) is sterling silver with gold plating.
Crude fineness testing is done with dilute nitric acid. Silver + dilute HNO3 yields a creamy white to brown liquid. Alloys containing Cu, Ni, and brass effervesce and yield a green, yellowish green or bluish green color. More precise technique involves gauging reaction and resulting color with Schwerter solution (HNO3 + KCr2 + H2O).

Current gold market prices

Gold prices for the last ten years have hovered between $300 and $400/oz t.

Pricing and Valuation

Average annual US gold prices for the last 25 years have ranged from about $160/oz t to more than $600/oz t.

PRECIOUS METALS

(GOLD, SILVER, PLATINUM GROUP)
All precious metal weights are given in troy ounce (oz t); there are 12 troy ounces per pound (lb. t) in contrast to 16 "regular" (avoirdupois) ounces (oz) per pound (lb.).
Gold (Au)
Purity or "fineness" denoted by karatage (K); 24 karat gold is pure gold.
12 karat gold is 50% gold and 50% alloyed metal.
Gold will alloy with nearly all base metals (Cu, Pb, Ni, etc.); different colors of gold are produced by alloying with different base metals. Common alloys are Ni and Cu.Gold purity can be tested with inexpensive devices that measure electrical conduction, or by the older method of gauging the extent of reaction with dilute acids. Pure gold is inert with respect to dilute HCl and HNO3; most alloys will react slowly in these acids. Gold plating or filled can be detected by testing a scratch in the item.
F.T.C. Guidelines governing sales of gold and gold jewelry in this country state the following:
1) If Karatage is to be stamped on, it must be at least equal to that designated or higher, and also must be accompanied by a trademark.
2) Terms "pure gold" and "solid gold" can only be used for 24 karat gold.
3) Term "gold" can only be used if gold content is 10 K or better.
4) Term "gold filled" applies only to items composed of a layer of gold pressed (not alloyed) onto a base metal where the weight of the gold comprises at least 1/20th of the total weight of the item. Fineness must be shown by stamp, e.g. "1/20 12k G.F." means the gold layer is 12 karat gold and comprises 1/20th of the total weight of the item.
5) Term "rolled gold plate" is the same, but gold comprises less than 1/20 of total weight; e.g. stamped "1/30 12 k G.P." means 1/30 of the metal weight is from 12 karat gold plate.
6) "Gold electroplate" or "gold flash" or "gold washed" mean a gold coating that is 10 k or better gold at least 0.000007 inches thick. A variant, "heavy gold electroplate" (H.G.E.P.) is at least 0.0001 inches thick.

Weight Conversion Table

1 gram (g) = 0.643 dwt = 0.0032 oz t = 0.035 oz av
1 pennyweight (dwt) = 1.555 g = 0.05 oz t = 0.055 oz av
1 troy ounce (oz t) = 31.103 g = 20 dwt = 1.097 oz av
1 ounce avoirdupois (oz av) = 28.3495 g = 18.229 dwt = 0.911 oz t

Weighing Precious Metals

The weight of a piece of gold jewelry is a factor that helps to determine its value. It is important because it is an indication of the amount of fine gold in an item of jewelry. Grams (g) and pennyweights (dwt) are the units of weight most commonly used in weighing gold. Gold and silver are almost always weighted in the troy system of weights where one pound troy equals twelve troy ounces and twenty pennyweights equals one troy ounce. The Avoirdupois weight system, where one pound equals 16 ounces, is used in the United States for most everything except precious metals. The following table summarizes useful weight conversions.

Fineness (Karat Value)

Since ancient times the purity of gold has been defined by the term karat, which is 1/24 part of pure gold by weight. Pure gold is equivalent to 24K. Gold purity may also be described by its fineness, which is the amount of pure gold in parts per 1000. For example, a gold ring containing 583 fine gold has 583 parts (58.3%) gold and 417 parts (41.7%) of other base metals.
Federal Trade Commission rules require that all jewelry items sold in the United States as gold shall be described by "a correct designation of the karat fineness of the alloy." No jewelry item less than 10K may be sold in the United States as gold jewelry

Properties of Gold

Gold in its pure state:
Has a melting point of 1945 degrees Fahrenheit (1063 degrees Celsius). When alloyed (chemically combined) with other base metals the melting temperature of the resulting alloy is changed. 18K yellow gold has a melting point of 1675 degrees Fahrenheit and 14K yellow gold has a melting point of about 1550 degrees Fahrenheit.
Has a specific gravity of 19.33. It is relatively heavy compared to most metals, such as silver (SG 10.7) or iron (SG 7.8). A notable exception is platinum (SG 21.4).
Is more malleable than any other metal and can be hammered into foil so thin that it is almost transparent.
Has a unique ductility property allowing it to be drawn into wire so fine it can barely be seen.
Is deep yellow in color. Its great reflectivity properties help keep its brightness and color from fading with time.
Will not rust, tarnish or corrode. Gold jewelry recovered from ancient Egyptian tombs is in the same state as when placed there over 4000 years ago.
Is softer than most other metals. On the Mohs scale of hardness (which is a measure of a gemstone or mineral’s resistance to scratching), gold has a hardness value of 2 to 2.5. Diamond has a value of 10. Pure gold may easily be scratched. Fortunately, gold becomes harder when alloyed with other base metals.
Is relatively scarce and therefore expensive. It is estimated that only 125,000 tons of gold have been mined the world over since the beginning of time.

Is able to bond with other base metals. This property gives rise to the many different colors available in modern gold alloys.

Precious Metals Gold

Gold is one of the most precious metals in the world. It is present in the rivers, seas, and the earth’s crust and trace amounts are present in plants and animals. It is, however, difficult and expensive to extract. In modern mining operations approximately 3 tons of ore are needed to extract one ounce of gold. The many desirable qualities found in gold, along with its scarcity, have made it the most popular metal for use in jewelry today.

Specific Enhancement Codes :

B: Bleaching - Use of chemicals to lighten or remove a gem's color
C: Coating - Use of surface treatments such as films, lacquers, etc. to provide color or other special effects
D: Dyeing - The introduction of coloring matter into a gem to give it a new color or greater intensity
F: Filling - Incorporation of colorless borax or other substances into cracks as a by-product of heating the stone, used only if such material is visible at 10x.
G: Gamma/Electron Radiation - The use of gamma or electron irradiation for the purpose of changing a gem's color, may be followed by a heating process to stabilize the color. Such stones do not exhibit residual radioactivity.
H: Heating - The use of heat to clarify, change color or create phenomena in gems. Any filler materials, which enter the gem, as a result must not be visible in fractures at 10x.
I: Infilling - The intentional filling of surface breaking cracks and cavities with a foreign material such as synthetic resins with hardeners (Opticon), glass or plastic.
L: Lasering - The use of a laser to drill into a stone and remove or alter an inclusion, refers specifically to diamonds
O: Oiling or Resin Infusion - The intentional filling of surface breaking cavities and cracks in transparent or translucent gems with a colorless oil, wax, resin or man-made unhardened resin.
R: Irradiation - The use of neutron bombardment to alter color. This process creates residual radioactivity and such stones must receive a Nuclear Regulatory Commission safety release prior to sale. Usually used in combination with other radiation and or heating treatments.
S: Bonding - The intentional use of a colorless bonding agent (usually plastic) within a porous gemstone.
D: Diffusion - The use of specific chemicals during a high temperature heating process for the purpose of penetrating the surface layer (usually to a slight depth only) with coloring or star-making chemicals. Such treatment is not generally accepted and stones sold with this enhancement must be specifically labeled as diffused.
W: Waxing/Oiling - The impregnation of colorless wax, oil or paraffin into porous opaque gems to improve appearance.

General Enhancement Categories :

1) N: Those natural stones which are not currently known to be enhanced by any methods, such as spinel, and therefore can safely be presumed untreated. The symbol "N" is used for these and may also be used in the case of other stones which are sometimes or often treated, which in the particular case are unenhanced. To use this symbol on sapphire, for example, which is generally heated means that the seller certifies that the particular stone was not heated and supplies a document such as an invoice or lab report so stating.
2) E: Those natural stones which are routinely enhanced by traditional methods, the particular stone given this designation, may or may not be enhanced. For example, since most emeralds are oiled an E would indicate such treatment, but would not cover non-traditional methods such as hardened plastic resins (like Opticon) which would require specific enhancement codes such as those listed below. Another example would be the use of E for aquamarine, which in most cases is heated prior to the sale of the rough to remove greenish tints. If the seller knows what specific treatment has been used, then a more specific code should be used.
3) Those gemstones for which definite information on standard treatments is known, or to which N and E codes do not apply, as they have been treated in non-traditional ways which must be specifically disclosed by the appropriate code and also in writing. For example, a ruby which has had fractures or cavities filled with glass would receive an I (infilling) code as described below. A Morganite, which is known to have been heated, would receive an H rather than the less specific, E.

Gemstone Enhancements

The following codes and definitions are adapted from the American Gem Trade Association's Gemstone Enhancement Manual, Edition 6.1 June, 1997, which is the industry standard for disclosure to consumers.

Diamond Shapes

The most common shapes of diamonds seen in jewelry are pictured above. They include: Emerald, Heart, Pear, Round Brilliant, Marquise, Radiant, Oval and Princess Cuts. Numerous variations exist on the above shapes, many of which may contain Trade marks as to the use of their names. Other common cuts not shown above include Baguettes (both straight and tapered), Triangle, Half Moon, Star, Cushion, Flanders, Asscher, as well as Fantasy Cuts. Often Colored Stones and increasingly more often, diamonds may be Mixed Cut. These stones may possess a crown (top) with one cutting style and a pavilion (bottom) with another. It is the combination of faceting styles which ultimately gives each stone it's own personality in the form of brilliance (reflected white light) and dispersion (refracted spectral colors).
The following diagrams will show many of the variations in cutting styles. Click on the pictures to see enlarged images.

Diamond

Diamond is the birthstone for the month of April. Besides being the most popular gemstone for engagement rings, diamond is the accepted anniversary gem for the 10th and 60th years of marriage.
The name "diamond" comes from the Greek word "adamas" meaning unconquerable-suggesting the eternity of love. In fact, diamonds have been the traditional symbol of love since ancient Greece.
Discovered about 2,500 years ago in India, the ancients believed they were splinters from the stars, perhaps crystallized lightening or hardened dewdrops.
Although diamonds are associated with being a colorless stone, they are occasionally found with a strong, bright color-green, red, pink, blue, canary yellow and amber. These "fancy" colored diamonds are highly prized.
Occasionally, to improve appearance, diamonds are laser-drilled and, sometimes infilled, where in a foreign substance is used to fill surface cavities or fractures rendering them less visible. Diamonds may also be irradiated and/or heated to induce "fancy" colors. This is usually detectable as a surface only enhancement and reads differently under a spectroscope than the much more rare natural counterpart. Recent highly technical processes incorporate high temperature and high pressure (HTHP) to remove some of the yellow tint that many diamonds possess. Only a small percentage of diamonds are of the necessary chemical type to respond to this treatment. Respectable laboratories, which use this technique, are using lasers to engrave their trademark on the girdles of these stones in a size so small it is only visible under magnification. They are appropriately disclosing this process to informed buyers. Unfortunately, stones are being discovered to have had the engraved trademark removed through recutting / repolishing in an attempt to deceptively remove the proof of enhancement and avoid disclosure.
Even though it is the most durable of gemstones, care should be taken to protect a diamond from sharp blows. Household chemicals may discolor or damage the mounting. To clean, you may use a jewelry cleaner, lukewarm soapy water and a small bristle brush, soak in a half-and-half solution of cold water and ammonia for 1/2 hour, or use a home ultrasonic machine with its recommended cleaner.