Carat
Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to gold purity.)
Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, color and cut. The majority of diamonds used in fine jewelry weigh one carat or less.
Because even a fraction of a carat can make a considerable difference in cost, precision is crucial. In the diamond industry, weight is often measured to the hundred thousandths of a carat, and rounded to a hundredth of a carat. Diamond weights greater than one carat are expressed in carats and decimals. (For instance, a 1.08 ct. stone would be described as “one point oh eight carats,” or “one oh eight.”)
HOW DID THE CARAT SYSTEM START?
The carat, the standard unit of weight for diamonds and other gemstones, takes its name from the carob seed. Because these small seeds had a fairly uniform weight, early gem traders used them as counterweights in their balance scales. The modern metric carat, equal to 0.2 grams, was adopted by the United States in 1913 and other countries soon after. Today, a carat weighs exactly the same in every corner of the world.
Why does diamond Carat Weight matter?
The truth is, it doesn’t matter. Think about it. When you look at a diamond set in a ring, what does your eye see? Does your eye see weight, or does your eye see physical size? Obviously, your eye can only see physical dimensions — light doesn’t carry weight information back to your eye. And if you think about it even more, your eye also doesn’t see the total physical size of the diamond, because most of it will be covered in jewelry. All you can really see when you look at a diamond is the size of its surface area on the top of the diamond. For a round diamond, that’s the diameter, and for other shapes, it’s a function of length and width. For simplicity’s sake, for the rest of this article, I will refer to diameter, but what I am writing applied equally to non-round shapes.
Now, obviously, there is a direct correlation between the diamond carat weight and the diameter of a diamond. It’s mathematically impossible for a 0.05ct diamond to have more surface area than a 1.00 carat diamond. But because cut qualities can vary greatly, there is a vast amount of variance in the range of possible diameters for any given carat weight. In my experience at Leo Schachter, a 1.00ct diamond can have a diameter that ranges from 5.60mm (a horrifically ugly deep diamond) all the way to about 6.60mm (a shallow “flat” diamond).
So as you can see, while weight should matter to you because it will help determine how much you are going to pay, what you should really be focusing on is the diamond’s cut grade and diameter. After all, wouldn’t you rather have a 0.90ct diamond that is 6.2mm and looks fantastic yet is cheaper than a 1.00ct diamond that is only 6.1mm and looks terrible?
Cut
The traditional 58 facets in a round brilliant diamond, each precisely cut and defined, are as small as two millimeters in diameter. But without this precision, a diamond wouldn’t be nearly as beautiful. The allure of a particular diamond depends more on cut than anything else.
Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the flashes of light, or sparkle, when a diamond is moved).
An understanding of diamond cut begins with the shape of a diamond. The standard round brilliant is the shape used in most diamond jewelry. All others are known as fancy shapes. Traditional fancy shapes include the marquise, pear, oval and emerald cuts. Hearts, cushions, triangles and a variety of others are also gaining popularity in diamond jewelry.
As a value factor, though, cut refers to a diamond’s proportions, symmetry and polish. For example, look at a side view of the standard round brilliant. The major components, from top to bottom, are the crown, girdle and pavilion. A round brilliant cut diamond has 57 or 58 facets, the 58th being a tiny flat facet at the bottom of the pavilion that’s known as the culet. The large, flat facet on the top is the table. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light.
In early 2005, GIA unveiled a diamond cut grading system for standard round brilliants in the D-to-Z color range. This system, the product of more than 15 years of intensive research and testing, assigns an overall diamond cut grade ranging from Excellent to Poor.
HOW Diamond Laboratories grade Cut: Proportions - Polish - Symmetry
The cut is the most important element to control brilliance, scintillation and fire.
The sparkling quality of the cut is to be determined by 3 separate factors:
1. Proportions
Too shallow and / or too deep cut diamonds will loose brilliance through the side and bottom.
The result is a dull diamond with less brilliance, affecting the ultimate value in terms of quality and price!
Excellent, Very Good, Good, Fair, Poor or Unusual
2. Polish
Finish grade or polish for ideal cut diamonds are described as following:
All facets of a diamond are carefully polished to eliminate all imperfections, characteristics such as abrasions,
scratches, nicks and polishing marks on the surface of the diamond to give the mirror shine and the final beauty touch.
Polish grading: Excellent, Very Good, Good, Fair, Poor or Unusual
3. Symmetry
is the balance and regularity / evenness of facets.
Facets are compared in opposing pairs, defined as following:
Symmetry grading: Excellent, Very Good, Good, Fair, Poor or Unusual
Triple Excellent cut
When proportions, Polish and Symmetry are graded Excellent it is named Triple Excellent
Ideal cut = Perfect cut = Triple Excellent + Hearts & Arrows = Best Value!
Symmetry: is the balance and regularity / evenness of facets.
Facets are compared in opposing pairs,
defined as following:
Very Good. (some laboratories describe this by Excellent)
Good. (some laboratories describe this by Fair)
Poor.
Unusual.
Hearts & Arrows Cut
Hearts and Arrows pattern is defined by perfect symmetry of the major facets with particular lengths of its lower girdle facets.
Hearts and Arrows is also named super ideal cut diamond.
Hearts and arrows is the pattern of ideal optical symmetry + excellent parallelism, particular lengths of lower girdle
facets and major facets, obtained by excellent cut of the the angles of the major facets and the minor facets.
Viewed from the crown, (TOP) the pattern has eight arrows.
Viewed from the pavilion, (BELOW) the pattern has eight hearts.
By special magnifying viewer you can see this.
HRD (the Diamond High Council), IGI and GIA grade Hearts and Arrows cut as H&A and by labeled images
Color
Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy-color diamonds, such as pinks and blues, which lie outside this color range.)
Most diamonds found in jewelry stores run from colorless to near-colorless, with slight hints of yellow or brown.
GIA’s color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or near-colorless. Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions.
Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
Clarity
Because diamonds formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes).
Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).
Every diamond is unique. None is absolutely perfect under 10× magnification, though some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewelers have never even seen one.
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) - No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) - No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) - Inclusions are clearly visible under 10× magnification but can be characterized as minor
Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader using 10× magnification
Included (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance
Some Facts
The most common mistake people make when buying diamonds is they purchase a diamond with a diamond clarity grade that is simply too high to appreciate in order to buy a “good investment.”
I worked in the diamond business for 6+ years. If you gave me a diamond with a VVS2 diamond clarity grade, it might take me a few minutes with a 10x powered loupe to find the actual pinpoint of an imperfection that is the “Very Very Small Inclusion.” I could find a VS1 in less time, but it’s only marginally larger than a VVS2. VS2s and SI1 diamond clarity grades can be spotted right away with a 10x powered loupe, but almost always still completely invisible to the naked eye. And even most SI diamond clarity grade diamonds cannot be seen by the naked eye.
Bottom Line Recommendation:
- Choose the lowest color and clarity that still look great to the naked eye, and then choose the largest diamond carat weight that still fits within your budget. But always keep in mind the cut quality, since a poorly cut heavier diamond can look smaller than an excellently cut lighter diamond.
- Diamond Cut Grade: For GIA Certified Diamonds, a cut grade of “Very Good” will look great. You will, however, be able to notice an improvement in brilliance by upgrading to “Excellent.” For AGS Certified Diamonds, a cut grade of “Excellent” will suffice, but you will notice added brilliance by upgrading to “Ideal”
- “Triple Excellent” or “Triple Zero” look pretty on paper, but you shouldn’t pay extra for Excellent (or AGS Ideal) Polish or Symmetry. You cannot detect the difference between Good (AGS Very Good) Polish and Symmetry and Excellent (AGS Ideal) Polish and Symmetry with your naked eye. In most cases you need a microscope to detect the difference.
- For Round Brilliant Cut Diamonds, don’t give too much credence to an online vendor’s cut grade. Only focus on the GIA or AGS cut grade on the certificate.
- White Gold / Platinum Ring
- Round: H-J – higher than H and you’re paying for a feature you won’t be able to appreciate
- Princess, Emerald, Asscher: G-I
- Everything Else: F-H
- Yellow Gold Ring
- Round: K-M – the yellow color of the gold is absorbed into the diamond color, so anything higher than K is going to look slightly yellowish anyway
- Princess, Emerald, Asscher: J-K
- Everything Else: I-J
Money Saving Tip: Buy a diamond in the I-K color range with Strong Blue fluorescence and your diamond will end up looking one to two color grades whiter!
- Buy the lowest diamond clarity you can that is still “naked eye-clean.” While this is impossible with most online vendors, James Allen has a fantastic tool they call a “virtual loupe” which allows you to view their diamonds at about 20x magnification. If you are unsure if the picture you’re looking at will translate to an “eye-clean” diamond, then please contact me and send me the link. I’ll be happy to take a look for you.
To wrap things up
The greatest myth about diamonds is that they are a smart investment. Edward Jay Epstein, in his industry-shaking exposè on the “Diamond Invention” entitled “Have You Ever Tried to Sell a Diamond?” clearly and emphatically puts this idea to rest. I recommend any prospective diamond buyer first read this article from start to finish. It’s important to be in the right frame of mind when making such a major purchase and not be influenced by all the magic and emotion thrown at you from DeBeers advertising.
Diamonds are a retail product just like any other. The product goes through various stages of production and distribution (mining, polishing, distribution, retail, and finally customer). As the diamond changes hands, each participant takes their cut. By the time the finished product ends up in the customers’ hands, the price is sufficiently inflated that you could never sell it without losing money. If cars lose 15% when they leave the lot, then figure most diamonds probably lose at least 30-40% when they leave the store.
