Carat-Weight: The earliest gem traders measured their stones by comparing their weight to the weight of the pods from the carob, or locust tree. These tiny carob seeds are remarkably consistent in weight, & this is where the term carat is derived from.
The metric carat, which equals 0.20 gram or 1/142 of an ounce, is the standard unit of weight for diamonds & most other gems. One carat is divided into 100 "points." A diamond weighing 50 points = 0.5 carat (ct.), & is expressed as one-half carat. The carat-weight of a diamond is the most obvious characteristic of a diamond & larger stones are often prized due to their rarity. It must be remembered, however, that the weight has no bearing on quality & two diamonds of comparable weight may differ drastically in price due to dissimilarities in cut, color & clarity. Diamonds of the same diameter may vary in actual carat weight depending on variations in their proportions. All other aspects being equal, the larger the carat weight, the more valuable the diamond is.
One Grain or "a one grainer":25 points or 1/4ct.; A diamond of approximately 1ct. would be called a 4 grainer, one ~ 1.5ct. would be a 6 grainer & a 0.5ct. stone a 2 grainer.
Melee:Diamonds weighing less than 1/5ct. (less than 20 points). Stones this size are set using various techniques as groupings in jewelry.
Weight Representation:In the U.S., the Federal Trade Commission requires that diamonds be weighed to one-thousandth of one carat (0.001ct.), but that the final weight can be rounded to the nearest half point (0.005ct.). This means that a diamond weighing 0.995ct. can be represented to you as a 1.00ct. stone. However, international convention is more strict & a weight can only be rounded to the next higher point (0.01ct.) if the actual weight reaches 9/10ths (0.009ct.) of a point. For example, the 0.995ct. diamond must be represented as a 0.99ct. stone & to be represented as a 1.00ct. diamond the stone must weight 0.999ct. before it can be rounded up to 1.00ct.
Value Per Carat:increases with carat size, because larger rough diamonds occur less frequently. In other words, 2 half-carat diamonds taken together will not cost as much as 1 one-carat diamond, as the one-carat stone is more rare. Also, a premium is added to diamond prices as they reach & exceed each 1/4ct. increment in weight.
Color: The color grade of a diamond refers to how closely its body color approaches colorlessness. The best color for a colorless diamond is, in fact, an absence of color. A truly colorless stone will carry a premium price & the larger that diamond, the greater the premium per carat.
Most diamonds have at least a trace of yellow, brown, or gray body color. Though a lot of diamonds will appear to be colorless, most actually possess subtle shade differences. These variances in color are due to traces of elements such as nitrogen & boron that become assimilated into a diamonds atomic structure during the original formation.
Most commonly, a diamond will have a hint of yellow or brown due to traces of nitrogen.
Diamonds with increasing shades of brown & yellow are referred to as champagne diamonds & diamonds with exceptional color, such as pink, red, green, blue & amber, are called "Fancies." With the exception of some natural fancy colors, such as blue, pink, purple, or red, the colorless grade is the most rare. Colors of high saturation such as red & green, which have no modifying secondary colors, are very rare indeed & command world record prices.
The rarest & most prized diamonds are those with no hint of color at all whose beauty is entirely dependent upon their optical properties. Such stones reflect all of the colors of the rainbow, & their value is great. All things being equal, other than the fancy colors, the closer a diamond is to colorless, the more valuable it is.
The color of the stone can be determined by using a GIA (Gemological Institute of America) Certified set of master stones &/or the Colorimeter, a computer which accurately grades the color of a polished diamond.
Factors Affecting Color:Other factors which can affect color include fluorescence, color enhancements such as high pressure, high temperature treatment (HPHT) & irradiation.
Fluorescence:produced by ultraviolet light from the sun, by black lighting or other long-wavelength UV source, occurs in an estimated 35% of gem grade diamonds. (Virtually all diamonds fluoresce when exposed to X-rays & this forms the basis for their identification & collection at mining sites.) The UV light excites electrons in the diamond crystal, which then release this absorbed energy in the form of visible light, producing a blue, or sometimes other color, of faint to very strong intensity. Once the light source is removed however, the fluorescence is no longer observed. If, in rare situations, light emission continues for a period after the exciting light has been turned off, the phenomenon is called phosphorescence.
Blue Fluorescence:if strong or very strong, may alter the perceived color of a diamond in a negative or positive way. For example, stones in the colorless/near colorless ranges (D-H) may appear milky or oily, detracting from their appearance. On the other hand, diamonds in the lower, more yellow color ranges (I & lower) may appear to have less yellow color due to the fluorescence, adding positively to their appearance. Thus, the trade will slightly discount prices of diamonds in the former category, while sometimes adding a very slight premium to those in the latter.
The presence & color (most frequently blue, but can be any color) of fluorescence & its intensity (none/inert, faint, medium, strong, very strong) are indicated on all GIA, GAL & AGS grading reports.
Irradiation:of diamonds using a nuclear reactor or linear accelerator, sometimes in combination with heating, is used to produce a variety of different fancy colored stones.
High Pressure/High Temperature (HPHT) treatment:is a process developed by General Electric whereby type IIa diamonds of low color (N-O) or even fancy brown color, can be converted to colorless/near colorless (D-H) forms by an annealing process involving high pressure & temperature.
There is some concern that these color-enhanced stones may come to market undetected, but new research has shown that they can be largely detected using expensive & sophisticated equipment. Similarly, the HPHT technique has also been applied to type Ia brown diamonds by several companies, yielding fancy yellowish green & greenish yellow colors. Pink & blue colors have also been produced by the same technique.
The Color Grading Scale: ranges from totally colorless to fancy yellow. The differences between one grade & another are very subtle, as can be seen by the number of grades within any one category.
Diamonds are graded for color only as loose, unmounted stones in the inverted position (table down, pavilion up) & under very specific conditions of lighting, background, the distance & angle of the observer in relation to the stone. A color scale has been devised by the Gem Trade Lab. of the Gemological Institute of America (GIA/GAL) divided alphabetically from D (the absence of color) to Z (fancy yellow color) & is recognized world-wide. Each letter grade represents a small range of color & not just a single color. Diamonds are color graded by being compared to a set of master stones.
DEF (Colorless)
GHI Near colorless; not distinguishable from colorless when mounted
J Very, very faint yellow
KLM Faint yellow. Color distinguishable to the trained eye.
NOPQ Very light yellow to intense yellow color.
RSTUVWXYZ Increasingly more intense color, gradually ranging into browns.
Effect of Color on Price:In general, as the amount of yellow in the stone increases, the value of a diamond decreases, that is until the fancy color grades are reached & then the value goes up again.
Cut:Regardless of the size or shape of a diamond, the cut will be the ultimate determinant of a diamonds brilliance & fire. Most round, brilliant-cut or fancy-shaped diamonds have fifty-eight delicately angled flat surfaces, called facets. The placement of each facet is intrinsic to the brilliance & beauty of the stone; if the cut is too deep, light will escape through the opposite side of the pavilion, or bottom, of the diamond before it can be reflected. Similarly, a shallow cut will allow light to pass directly through the pavilion. The cut of a diamond is graded on the basis of how well the diamond handles the light coming into it from above.
The proportions & finish of a polished diamond determine its final face-up beauty. A well proportioned diamond will return most of the light back to the eye for maximum brilliance & dispersion.
Sparkle is created by the facet placement & the surface polish.
How a Diamond Handles Light:1. When a diamond is cut to good proportions, light is reflected from one facet to another & then dispersed through the top of the stone.
2. If the cut of the diamond is too deep, some light escapes through the opposite side of the pavilion.
3. If the cut is too shallow, light escapes through the pavilion before it can be reflected, thus reducing brilliancy.
Brilliance:is the total light reflected to the eye from both surface & internal reflections.
Dispersion:is the separation of white light into its spectral (rainbow) colors & is caused by its refraction, which bends each wavelength of light a little differently to cause separation into individual colors.
Scintillation:is the flashing or sparkling of light which occurs when either the diamond or light source are moved.
Finish:This includes polish & symmetry, is also an important contributor to a diamond's beauty.
Polish:Features largely describe the condition of the surface of the stone. This includes abrasions of the facet junctions, the culet, rough, bearded girdles, nicks, pits, scratches & polishing marks if they do not affect the clarity grade. You will remember some these elements were also listed as blemishes in the clarity-grading scheme. However, if the blemishes are not serious enough to affect the clarity grade, they are included under polish as part of the finish grade.
Symmetry:Characteristics include many features of poor &/or careless workmanship such as an off-center table or culet, a table not a regular octagon shape, an out-of-round or wavy girdle, non-parallel girdle/table, facets which don't meet or point properly or are misaligned between the crown and pavilion, naturals & extra facets which are not graded under clarity.
Proportion:The full realization of the potential of a diamond's brilliance, dispersion, scintillation & getting the proper balance between these three elements is achieved mainly through proper cut proportions.
The Important Proportions:1. Table size
2. Crown height and angle (angle of the bezel facets with the girdle)
3. Pavilion depth and angle (angle of the pavilion facets with the girdle)
4. Girdle thickness
5. Culet size
Make:This is a trade term used to describe how closely the proportions of a brilliant cut diamond are to an "ideal". For stones approaching these proportions a diamond is said to be of good or fine make & for those with problems of proportion are referred to as being of fair or poor make.
Effect of Cut Quality on Price:Cut quality commands a premium for two reasons. First, you are paying for a highly skilled diamond cutter's time. It can take many hours to get all the proportions and angles to fall within the Ideal or Super Ideal ranges. Second, more of the diamond is lost in the cutting process, because the goal is not to cut the heaviest diamond, but the best performing diamond.
Grading Clarity:This describes the clearness or purity of a diamond. This is determined by the number, size, nature, and location of the internal (inclusions) & external (blemishes) imperfections.
Nitrogen & other elements trapped within a stone during its formation effect the ultimate color, & minerals embedded in a diamond during crystallization will influence the stones clarity.
These natural characteristics, called inclusions, make each stone unique; they're natures way of personalizing each diamond.
Gemologists even use these inclusions to determine a diamonds age. The fewer the inclusions, however, the more rare & precious the stone will be considered because nothing will interfere with the passage & reflection of light. The number, color, size & position of any inclusions will specify a diamonds clarity, but most will not endanger its durability. To establish a diamonds clarity, it must be examined by a trained eye under a 10x magnification; the fewer the inclusions, the more valuable the diamond will be.
Be aware!Two methods used to enhance the clarity grade given to a diamond are laser drilling & fracture filling.
Laser drilling is the process in which a laser is used to drill a tiny hole into a diamond & the black of the imperfection is then removed.
The second treatment is fracture filling. This method is not permanent & therefore not recommended.
Blemishes & Abrasions:These are tiny nicks on facet junctions or the culet; caused by wear or coming in contact with other diamonds.
Extra Facets:These are small facets placed to remove imperfections; not part of the cutting style. (Not to be confused with Added Facets which are added symmetrically & are part of the cutting style).
Naturals:This is part of the original crystal surface remaining on the polished stone, frequently in the area of the girdle.
Polish Lines & Marks:These are tiny parallel lines or surface clouding left by irregular polishing or excessive heating during polishing, respectively.
Rough Girdle:A grainy or pitted girdle surface usually caused by poor workmanship.
Surface Graining:Structural irregularities in crystal growth; may appear as faint lines, causing grooved or wavy surfaces & often cross facet junctions.
INCLUSIONS:
Bearding:
tiny feathers extending inward from a bruted girdle surface. (Bruting is the process of rubbing two diamonds together to achieve the rounded shape of the diamond).
Cavities & Chips:Large/deep openings, and small/shallow openings in the diamond's surface, respectively.
Clouds:Hazy or milky areas of many very small, usually crystalline inclusions.
Feathers:Cleavages or fractures often white & feathery in appearance. (There are 4 cleavage planes in diamond, which run in octahedral directions. Fractures are breaks along planes other than cleavage planes & may alternate with them to form step-like feathers).
Included Crystals:Mineral crystals, such as garnet or peridot & contained inside a diamond.
Indented Naturals:Natural rough surfaces that penetrate the stone & may distort the girdle outline.
Internal Graining:Regions of irregular crystal growth that may appear as milky or colored lines or streaks, or may be reflective.
Laser Drill Holes:A tiny tube made by a laser; the surface opening may resemble a pit, while the tube usually resembles a needle.
Needles:Needle-shaped included crystals.
Pinpoints:Areas of minute, dot-like inclusions.
Twinning Wisps:Cloudy areas produced by distorted crystal growth.
Clarity:All clarity grading is performed at 10-times magnification using a hand loupe or gemological microscope under both artificial daylight & darkfield illumination conditions. Reflected light is used to detect & evaluate blemishes & darkfield light for inclusions. It's the face-up view that usually sets the clarity grade, however the face-up, pavilion & table-to-culet views are all taken into consideration during grading.
Clarity grades are largely determined by the collective visual appearance that a stone's inclusions exhibit in relationship to the size & shape of the stone. It is the consideration of the size, position, number, color/contrast & nature of these inclusions, which leads to the final clarity grade.
Clarity Symbol Meaning Definition:F Flawless Free from all blemishes, or inclusions.
IF Internally Flawless No inclusions visible at 10x magnification.
VVS1 Very Very Slightly Included #1 Inclusions that are extremely difficult to detect at 10x.
VVS2 Very Very Slightly Included #2 Inclusions that are very difficult to detect at 10x.
VS1 Very Slightly Included #1 Minor inclusions, difficult to detect at 10x.
VS2 Very Slightly Included #2 Minor inclusions, somewhat difficult to detect at 10x.
SI1 Slightly Included #1 Noticeable inclusions, easy to detect at 10x.
SI2 Slightly Included #2 Noticeable inclusions, very easy to detect at 10x.
SI3 Slightly Included #3 Some inclusions may be seen with the unaided eye.
I1 Included #1 Obvious inclusions. Somewhat easy to detect with the unaided eye.
I2 Included #2 Obvious inclusions. Easy to locate with the unaided eye.
I3 Included #3 Obvious inclusions. Very easy to detect with the unaided eye.
The above clarity grading scheme is in accordance with the GIA (Gemological Institute of America).
DiamondsIt seems nearly impossible to watch TV or open a newspaper without seeing something about man-made diamonds. For hundreds of years science has tried to create a perfect synthetic diamond. Finally, 21st-century technology has made that prospect a reality.
There are many reasons to purchase synthetic diamonds instead of the mined variety. The prices charged for mined diamonds are, in the very best verbiage, an illusion. To put it more bluntly, Cecil Adams, in his award-winning newspaper column "The Straight Dope" says: "Diamonds are a con, pure & simple." Diamond prices are largely controlled by the DeBeers diamond cartel & they are not a fair reflection of diamond scarcity. Additionally, studies show that one out of three diamonds sold in the US today has been altered to artificially increase its value. Further studies have shown that on average a couple pays 40% too much for their diamond engagement ring.
Beyond deceptive pricing, there are the issues of "blood diamonds", forced child labor, and a myriad of other disturbing diamond facts.
Recently, socially conscious celebrities such as Gwyneth Paltrow, Minnie Driver, and Angelina Jolie have made a vocal issue of wearing only synthetic diamonds to the many gala events they attend.
Good synthetic diamonds are virtually indistinguishable from the mined variety, but without the baggage, and additionally, they cost thousands of dollars less. But, which synthetic diamond is the best choice?
There are many types of man-made or synthetic diamonds available. The choices are numerous, but unbiased information is scarce. Here is an overview and comparison of the synthetic diamonds currently unavailable on the market:
Cubic Zirconia:The grandfather of simulated diamonds, Zircons are available widely. In their best examples, CZ's are actually a fairly decent diamond replica. Unfortunately, the commodity-like availability and vast differences in quality have made the stone synonymous with low-cost fashion jewelry. Perhaps a good choice for cheap bling, but not for fine jewelry.
Russian Diamonds:Including Russian Brilliants, Russian Stars & others, they are in fact nothing but high quality cubic zirconias. This is not mentioned prominently on their web sites & they will only cop to it when pressed, but that is the fact. Russian diamond simulates are priced around $280 per carat.
Russian Diamonds are a fine jewelry selection & are usually mounted in quality precious metal settings.
Moissanite:Moissanite is a lab-created mineral that is a very good diamond stimulant. Moissanite has been on the market as a fine jewelry choice since the early 90s & has picked up quite a few fans. Moissanite is a hard mineral that, like diamond, will cut glass. There are a couple of minor downsides to moissanite however. First, it is quite expensive, (though still cheap compared to diamonds) usually priced about $500 per carat for good samples.
Secondly, moissanite does not have the same optical qualities as diamond & there are several indicators that make them easy to spot with the naked eye for an experienced practitioner. It is difficult to produce a pure white moissanite & they often appear slightly green when viewed in natural light. Also, moissanite has significantly higher radiance & brilliance factors then natural diamond, causing them to appear "too sparkly" to some. Overall though, moissanite is a beautiful synthetic diamond choice.
Diamond Nexus:
Diamond Nexus gemstones are the result of a fairly new scientific advancement in processing technique & have only recently been available in the United States.
Diamond Nexus gemstones are excellent diamond stimulants & come very close to matching the properties of mined diamonds at many different comparison points. They cut glass, being virtually identical to a Sapphire on the Mohs (hardness) scale registering in at 9. They refract perfect "hearts & arrows". They have radiance & brilliance readings extremely close to flawless diamond.
Best of all, they are currently introductory priced for the U.S. market & are a steal at $79 per caret. Diamond Nexus gemstones are only available in precious metal, solid-gold settings.
White Sapphire:Sapphire is the second hardest natural mineral on the Mohs scale, surpassed only by diamond. They are, unlike the others in this review, a natural stone. Their radiance & brilliance are not up to the standards of diamond however. Nevertheless, quality white sapphires priced at around $220 per carat are a good diamond alternative.
Gemisis Cultured Diamond:Gemisis diamonds are beautiful & almost perfect diamond replicas. Unfortunately, they are not available in a clear, white color, so they are not a good choice for traditional diamond settings. However, if a yellow, orange or pink diamond is what you crave, Gemisis offers stunning choices in beautiful precious metal, fine-jewelry settings.
Recap: Synthetic diamonds offer many advantages over the mined variety. You can buy with confidence, knowing that you are getting exactly what you paid for & have not been the victim of diamond pricing chicanery. If you are concerned with the world around you, you can have a clear conscience, knowing that your money has not contributed to the support of an unethical & abusive industry.
However, there are many choices of synthetic diamonds, with varying degrees of quality. Take a little time to review the seller's information to get a clear idea of what the science is behind the gemstones you are buying.
If it comes down to the money, an investment is not in your mind but you want some cheap bling, I believe the best choices are quality Moissanite stones or the new Gemisis Cultured Diamonds. Personally myself I go for the natural diamonds. Why buy something that will be worthless on the turn around?
