Most people know that a diamond started life as a lump of carbon (like a charcoal briquette) subjected to intense heat and pressure under the earth – transforming it into the hardest (and most desirable) material known to man.
Diamond Basics – The Four C’s
There are four essential aspects of a diamond that determine it’s beauty, quality, and value. They are known as “The Four C’s”. Traditionally, they are listed in this order of importance to the beauty of the stone: cut, color, clarity, and carat weight.
In the diamond trade, the cutting and proportioning of a diamond (referred to as “make”) are of critical importance. The make of a diamond has an enormous influence on the beauty of the stone. Faceted diamonds and transparent gems have crown facets which optically act as windows, and the bottom or pavilion facets are mirrors. The better the cut, the more beauty and life to a stone.
There are three components to the light that returns to the eye from a diamond. Brilliance refers to the light that enters the diamond and returns as white light. Dispersion (or fire) is the light that is dispersed into spectral color and return as flashes of rainbow. Scintillation is the light that is reflected off a facet without entering the diamond. A balance of these three components creates what we perceive as the optimal beauty in a diamond.
In round diamonds, an “IDEAL” cut is one that is cut to within strict proportional parameters, maximizing light return. Ideal cuts are more expensive because it takes longer to cut them, thus the yield from the rough crystals is less. Recently developed instruments have allowed for diamonds to be evaluated based on actual performance rather than on the traditional mathematical model used for an ideal cut. With these instruments it is possible to see where a diamond is “leaking” light through the pavilion.
In the other diamond shapes, (princess, oval, emerald , and marquise) there is no accepted “ideal” cut, but the American Gem Society Laboratory is in the process of developing parameters for measuring the performance of these cuts.
This is one of the first things people notice when judging a diamond. The closer to “white” (i.e. clear or colorless), the better. Few diamonds are absolutely colorless, those however, that are graded as a “D” color on the GIA (Gemological Institute of America) scale are very close. There is no A, B, or C color. “D” is the best there is, although E and F grades are also considered extremely fine and are also called “colorless”. No other color may be called colorless by Federal Trade Commission rules and regulations.
The GIA scale runs all the way to Z, with increasing amounts of yellow/brown associated with each letter. (There are several other color grading systems in use, but the GIA is the most used and the most informative).
Diamonds, although rare to begin with, are even more rare if they have strong shades of blue (like the Hope diamond), or red, green, bright yellow, etc. These are known as “fancies” in the trade and there is no comparable letter scale to grade them.
As a product of nature, very few diamonds are totally flawless. Nearly all contain imperfections such as tiny black or white specks, minute cracks, grain lines, etc. These imperfections are called “inclusions” if they are internal to the stone, and “blemishes” if they are on its surface.
A clarity grade is really a rating of the number, size, severity, and type of inclusions- the fewer/smaller the number of imperfections, the more fire and brilliance the diamond will have. The light entering the crown, won’t have as many obstacles inside the stone preventing light return.
Again, there are many different grading systems in use, but the most commonly used one is the GIA scale. The American Gem Society scale for color, clarity, and cut goes from 0 (the best) to 10.
FL Flawless. No visible flaws under 10X-loupe magnification.
IF Internally Flawless. No internal flaws. Only minor external blemishes.
VVS1 Very, Very Slightly Included. Very difficult for even a trained observer to detect.
VVS2 Very, Very Slightly Included, although little more than VVS1.
VS1 Very Slightly Included. Inclusions still only visible under magnification.
VS2 Very Slightly Included, although little more than VS1.
SI1 Slightly Included. Flaws may be visible without magnification on side or back.
SI2 Slightly Included, although little more than SI1.
I1 Imperfect. Flaws may be seen with naked eye.
I2 Imperfect. More flaws than I1. Integrity of stone may be at risk.
I3 Imperfect. More flaws than I2. Stone lifeless and dull, integrity of stone is usually at risk.
4. Carat weight
The easiest aspect of a diamond to understand is its carat weight. Note that it is a weight, not a size. A carat (abbreviated “ct”) weighs one-fifth of a gram or 200 milligrams. There are 100 “points” to a carat. Therefore a ½ carat diamond might also be referred to as a 50 point stone.
People commonly associate carat weight with a certain size of diamond. They expect a “1-carat” diamond to look a certain way. To some extent this is true, but there are other factors that affect how big a diamond looks, notably the cut.
Naturally, carat weight affects price - however in a “nonlinear” way. That is, a diamond twice as big will cost much more than twice as much. Larger diamonds are rarer and therefore command a higher price per carat and, thus, a higher total price.
Many people are unaware that a number of techniques are used to improve the clarity of diamonds by removing or hiding imperfections.
Two very common techniques are laser drilling and fracture filling.
1. Laser Drilling
Many diamonds come from the earth with tiny black carbon specks inside them. Even if they are hard to see, they tend to scatter light and reduce the brilliance of the diamond.
About 25 years ago, high powered laser beams were first used to “burn-out” these impurities.
To reach the “inclusion”, a laser drill is used to create a tiny hole reaching deep inside the diamond. Often the laser’s heat will vaporize the speck. If not, acid is poured into the hole, usually dissolving the spot or bleaching it to a less noticeable white color. The holes are so small in diameter, it’s very difficult to see that the diamond has been drilled. Looking at the side of the stone in very bright light may show some thin “threads”.
Reliable diamond grading reports will always indicate when the stone has been laser drilled.
The Federal Trade Commission has recently revised the “Trade Practice Guides” for the jewelry industry, and surprisingly, has omitted laser drilling from its list of diamond treatments that must be disclosed to the public.
Normally, the FTC requires disclosure if the treatment: (1) is reversible (i.e. not permanent), (2) requires special care and handling (different from an untreated gem), and (3) substantially affects the diamond’s value.
Laser drilling is permanent, and the treated gems don’t require any special care. However, drilled diamonds are worth less than un-drilled ones of otherwise equal size and equal grade.
When you’re spending your hard-earned money on a diamond, you deserve to know the truth about what you’re buying. At Grimball Jewelers, we strive to disclose any treatment used to enhance a diamond sold at our store.
2. Fracture Filling
Sometimes, a chemical substance is used to fill small cracks in a diamond. The effect of this treatment can be very dramatic, turning a very “ugly” diamond into one that is remarkably brilliant.
However, a treated, clarity-enhanced diamond is worth far less than one that is naturally beautiful. There is nothing inherently wrong with gem enhancement- as long as you know what’s been done to the stone, and you’re not paying for one thing and receiving another.
Other Enhancement Techniques
There are various chemical coatings that can be used on a diamond to temporarily enhance its color.
Radiation treatments can be applied to off-colored diamonds, turning low-value brownish yellow stones into expensive fancy colored diamonds (pinks, greens, blues, etc.). This is not fraud as long as it is disclosed. However, this treatment is difficult to detect except by a gem lab, and oftentimes the diamonds are misrepresented as natural.
At Grimball Jewelers, we double check every diamond before it is shown to you or placed in our showcases- you can buy with confidence.
As you’d expect, there’s been a lot of interest in creating artificial diamonds in a laboratory - a form of modern day alchemy.
Industrial-quality artificial diamonds have been available for decades and are used in grinding wheels, drill bits, etc. Industrial diamonds are small and appearance is unimportant.
After the breakup of the Soviet Union, numerous crystal-growing labs sprang up in Russia and are now producing created diamonds in good qualities and increasing sizes.
Most created diamonds are less than one carat in the rough. Since 30% to 70% of the rough material is removed during cutting, the majority of created diamonds end up as fractional carat faceted stones. However, the growers have recently started producing rough stones in 3-carat sizes, and we therefore expect to see full-carat (and larger) cut diamonds on the market soon.
Nearly all created diamonds are an intense yellow-orange “fancy” color, due to nitrogen introduced during processing. They’re very pretty, but the market for near colorless diamonds is much larger than for the fancies. The crystal growers are working on this problem, and we can expect to see “I” color grades and better (all the way to “D” and “E”) in the near future.
Clarity can be very good in synthetics, as high as GIA graded VS1. It is becoming increasingly important to deal only with well-educated jewelers who have trained Gemologists on staff to protect your interests when purchasing a real diamond.
Whereas a synthetic diamond is an actual diamond created in a laboratory, a simulant is a pretender- another “diamond-like” looking stone that is substituted for the real thing.
1. Cubic Zirconia (CZ)
When it first became commercially available many years ago, cubic zirconia fooled quite a few people. It doesn’t anymore, and many can tell it’s not a real diamond at arm’s length. Nonetheless, there are some good fakes out there, and you need to be careful if dealing with a seller you don’t know well.
Very recently introduced to the marketplace, moissanite is another simulant. Its physical and optical properties are much closer to a real diamond’s. Moissanite is strongly doubly refractive, so it will pose no serious identification challenge to a knowledgeable gemologist.
Colored Gems & Treated Gems
Two commonly “accepted” colored gem treatments are the “oiling” of emeralds and the “cooking” of sapphires and rubies. However, fracture-filling of emeralds and glass-filling of rubies is controversial.
1) Oiling Emeralds
Nearly all natural emeralds have extensive internal flaws. The appearance of these stones can be markedly enhanced by placing in a vacuum chamber and immersing them in cedarwood oil (or another colorless oil). When the vacuum is removed, the oil is pulled into the minute spaces between fracture planes, making them less visually apparent. This also allows light to travel further in the stone without interruption, which results in the stone having a richer, more vibrant color (often several shades darker than before it was oiled).
This treatment can produce a remarkable change in the appearance of an emerald, greatly enhancing the beauty and clarity of the stone.
However, over time, cedarwood oil can leak out of the stone. It may be necessary to retreat the emerald every few years.
In recent years, several alternative filling materials have come to market. The most famous is Opticon. Opticon and other epoxy rosins are used in conjunction with hardeners. This results in a more permanent treatment, however, they can sometimes cause discoloration, and may be impossible to completely remove for retreating the stones.
Most of the emeralds we sell at Grimball Jewelers are from Eternity Emerald which has a proprietary process for treating emeralds which is permanent with a lifetime guarantee. These can be steamed and cleaned like any other gem.
2) Heat Treating Sapphires and Rubies
Sapphires and rubies are now almost always subjected to high heat in a gem furnace to improve their transparency and color. A well-known side effect is increased brittleness of the gems. This can result in the facet edges becoming abraded more rapidly than they otherwise would. Unless accompanied by a recognized gem lab report such as one from the American Gem Lab (AGL), you should always assume that your rubies and sapphires have been heat treated.
3) Fracture Filling
As opposed to oiling (which has become an “industry-standard” practice), fracture-filling of emeralds and glass-filling of rubies is a controversial yet also common practice.
At Grimball Jewelers, we strive to tell you about any treatment or enhancement that your stone may have had.
Most jewelry sold today is not 100% gold (not even “solid gold” pieces). Pure gold is too soft and easily damaged – so it is alloyed with other metals for strength and durability.
Pure gold is 24-karat (abbreviated 24K). Here is a handy table listing the amount of gold for in each karatage:
In the United States, jewelry must be at least 10K in order to be sold as real gold. However, in some other countries the karatage requirement is lower. In Canada, the legal minimum karatage is 9K, while in Mexico it is 8K. You will see the “karat mark” stamped on most gold jewelry. Please don’t confuse karat with “carat,” which is a measure of weight for diamonds and other gems.
2) Gold Colors
Silver, copper, nickel, and zinc are commonly used as alloying metals. Different combinations and proportions of these elements are used to create different gold colors such as white, rose, or green gold. Yellow gold remains the most popular, and the higher the karatage, the deeper and richer the color will be. Naturally, the higher the karatage, the greater the cost.
To protect the consumer from underkarating, U.S. law requires that any piece of jewelry displaying the karat mark also be stamped with the manufacturer’s trademark or hallmark. Often, the country of origin is stamped as well.