4C’s Guide

Set a budget

Natural diamonds grow deep inside the earth, while lab-grown diamonds are synthesized at factories.

GIA created the 4Cs (Color, Clarity, Carat, Cut) system to help consumers shop for diamonds without a need for a gemological degree. There is a reason similar-looking diamonds are priced differently, and 4cs is a simple way to understand why. Using the 4C system, color, clarity, and weight can be dialed up or down to find a combination that fits the budget. 

Often overlooked, the Fifth C is craftsmanship – the jeweler’s ability to take advantage of the stone’s unique features to enhance its presentation is crucial. Conversely, a poorly made ring can reduce even the most beautiful diamond to a dull pebble.

Miracle on 47th Street

– Do you have a 3-carat diamond?
– Yes, we do.
– Top color, ideal cut?
– Yes. What is your budget?
– 500 dollars
– … You are in luck! We have a 3-carat flawless diamond, and it’s only $500!
– You are kidding!!!
– Yeah…. But you started it!

Realistic expectations

Be realistic with what size and grade diamond is affordable on your budget. Diamonds are an openly traded commodity, so the prices are uniform across the globe. You get what you pay for.

A diamond engagement ring indicates a social status but does not determine it. Spending more than you can afford to show off is not smart. There is always a possibility of an upgrade in the future. Without a microscope, most grades cannot be told apart except by what’s left in your bank account.

Select a diamond grade

Color and carat weight dramatically affect the price, while clarity and cut have a lesser effect. To find your target grade, first decide what combination of two parameters is most important to you:

  • budget and size
  • budget and grade
  • size and grade

Tooltip and informationWhat diamond size can you afford? Use our exclusive diamond affordability calculator to find out.

selecting a diamond illustration

Most popular grades
Tight Budget: J-K/SI-I –
Smart Choice H-I/ SI1+ (VS1+ for step-cuts)
Premium: F-G/VS+
Vanity: D-F/VVS+
Investment: D-E/IF-VVS1

Pick color

diamond color scale

Diamond color grade significantly affects a diamond’s price because it reflects how rare the stone is. Colorless diamonds are rare but not necessarily the best-looking because a drop of warm tinge can bring a balanced and natural look. Some feel that D-E diamonds have a somewhat unnatural look, similar to cubic zirconia. 

The sweet spot is the G-H color range with natural diamonds and E-F with lab-grown.

Pick clarity

Diamond clarityscale

Moderate inclusions are gifts of nature, providing a generous discount while being virtually undetectable. According to GIA, grades above SI2 are eye-clean. In reality, most SI grades are not eye-clean, meaning some people might be able to see the inclusions without magnification. “Eye-clean” is a subjective opinion that depends on eyesight, lighting conditions, depth perception, and even mental condition.

Eye-clean SI1 is a sweet spot for a brilliant cut. VS2 is the lowest recommended clarity grade for step-cut emeralds or Asscher diamonds because facet reflections do not mask inclusions well.

Carat size diamond weight estimator

 As the diamond weight increases, so does the price, but not incrementally like other commodities. At certain points, diamond prices jump exponentially, for example, at  1, 1.5, 2, 2.5, 3, etc., carat marks. For example, diamonds ranging from 1.00 to 1.49 carats are priced similarly per carat. But once the 1.5-carat magic number  is reached,  the diamond’s price per carat increases dramatically.

Choose Carat Size

Diamond size is a measure of weight expressed in carats, not carrots. Its physical dimensions do not necessarily correspond to its weight, particularly for fancy shapes.

Buying a diamond of a certain carat weight is driven by peer pressure and social status, but sacrificing the size for better quality is a good strategy. A low-grade diamond is a waste of money, regardless of its size. 

A person’s height, body type, or the length of their fingers has nothing to do with a  diamond size. However, the ring style and finger size must be considered when targeting a certain carat size. 

Choose Cut

Diamond shape and diamond cut are two different things. The preferred diamond shape selection is based on personal taste; the most popular is a round brilliant. Diamond cut is the degree of artistry and precision in faceting execution.

Only round diamonds have GIA cut grade; fancy-shaped diamonds do not have a grade for a cut. A GIA “excellent” cut grade is essential for a diamond to guarantee its beauty and superb light return. Symmetry is the key to modern fancy-shaped diamond excellence but not antique cuts.

Diamond Beauty

One man’s meat is another man’s poison

Diamonds bring happiness; otherwise, they would be worthless. The regret of buying a junky diamond lingers long after the joy of scoring a bargain is forgotten. A diamond grade is not a measure of a stone’s beauty but is a mere hint at its scarcity. Beauty is in the eye of the beholder. A perfectly symmetrical, completely void of color and inclusions diamond is not superior; it is just one of the countless variations. The measure of beauty depends on personal taste. 

Diamond Trivia

  • Diamonds are formed deep in the earth at depths between 87 to 118 miles underground. 
  • Diamond is the solid form of carbon, crystallized in a cubic structure.
  • Diamonds come in every color, although some colors, such as green or red, are extremely rare.
  • Every diamond in the market is millions or billions of years old. They existed long before dinosaurs roamed the earth.
  • The largest diamond, called Cullinan, was discovered in South Africa in 1905. It was 3,106.75 carats and weighed more than 1.3 pounds.
  • There are diamonds in space. Scientists have discovered distant planets and stars made almost entirely of diamonds. One of them, 55 Cancri e, is believed to be a one-third diamond.
  • 80% of all diamonds are located in New York City. 

Diamond cut is a structure, design, and execution of the shape, proportion, symmetry, facet pattern, and position. Two essential types of diamond facets are step- and brilliant style. Most people are familiar with kite- and triangular-shaped brilliant facets. Round and fancy-shaped diamonds, except for emerald cuts, have brilliant faceting. Step-cut diamonds such as emerald cuts, Asscher cuts, and baguettes have rectangular or trapezoid facets. A few unusual diamonds with a mix of steps and brilliant facets are called “Mixed” cuts.

The cut significantly affects a diamond’s optical properties; it determines how well the stone reflects and breaks the light. Round brilliants with excellent cut, symmetry, and polish grade are called “ideal cut diamonds.”

Sometimes these diamonds are designated as Triple X, XXX, or ExExEX. Some ideal cut diamonds with a specific pattern of facets can be classified as “Hearts and Arrows” or “Hearts & Arrows.” The idea that an ideal cut is inherently more beautiful is preposterous. Many people find a diamond with a small degree of asymmetry more attractive. The reflections of a perfectly symmetrical diamond lack randomness that make the stone come alive. A precursor of the ideal cut, the “American Standard” cut, was developed in 1919 by Polish engineer Marcel Tolkowsky. His formula was perfected over the years, resulting in the ideal diamond cut. 

The GIA cut grades are “poor,” “fair,” “good,” “very good,” and “excellent.”

What makes a diamond sparkle?

A property called “sparkle” does not exist. The word “sparkle” refers to a combination of brilliance and dispersion. The brilliance is a repeated blinking of diamond facets in random order. At the same time, dispersion is the diamond’s ability to scatter and polarise light, causing the rainbow effect called “fire” in diamonds.

Some diamonds are cut to maximize brilliance, others for fire. Brilliant cut maximizes brilliance at dispersion’s expense. Antique and step-cut diamonds, popular when ballrooms were still lit with candles, are cut to maximize the fire.

Diamond Ratio

The length-to-width ratio is a measure of a stone’s elongation.  The L/W ratio is important for elongated diamond cuts such as emeralds cuts, cushions, ovals, radiants, and to a lesser degree, other shapes.

The ratio is determined by dividing the stone’s length by its width. The L/W ratio is always one for square-proportioned diamonds such as rounds and Asschers (elongated Asschers are called Krupp-cut diamonds).

Very expensive alphabet

The GIA diamond color grading system is widely used and universally accepted. It is a linear scale that ranges from D (colorless) to Z (light yellow or brown). Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by manually comparing their pavilion (flipped upside down) to a master set of stones under controlled lighting and precise viewing conditions. Diamonds up to the I color do not have a noticeable yellow color component. Their difference is the overall brightness. The GIA color grading system is based on the premise that colorless diamonds are rare and not because people find them more attractive. As the color of a diamond moves away from colorless, it becomes less desirable to most people until the color saturation increases enough for the diamond to become a fancy yellow. 

Color and price

The diamond color is only one factor that affects its value. Other factors, such as clarity, cut, and carat weight, are also important, but color affects the price most dramatically despite being the least perceivable property. This is because the material’s color is permanent and cannot be changed, unlike cut and clarity, which can be improved by re-cutting. The carat weight can also be reduced without affecting the diamond’s face-up size. GIA is an absolute authority on diamond grading, so their grades are accepted at face value to evaluate the cost. Other labs, including AGS, EGL, IGI, and GRS, are inconsistent, and their grades are often padded. 

Fifty shades of white

Up to an I-color, the amount of impurities is microscopic and registers with the human eye only as a colorless grey component. That gives diamonds within the D to I-color spectrum a difference in brightness. Most people start perceiving a yellow component in diamonds starting from J-K colors. Most jewelers agree with Tiffany’s opinion that any diamond above J is purely white without a trace of yellow.

Warm colored diamonds

The word color makes people think that any diamond below D is yellow. This is misleading. In reality, diamonds are white (or, more correctly, colorless) with only a small degree of warm tint. The hint of yellow gives a diamond a natural look, just like a warmer spectrum makes natural light more pleasing than cold fluorescent light. Those who appreciate the beauty of a warm-toned diamond have an affinity for finer things in life, such as antiques and art. Until the 20th century, lower color grades were not detrimental to the diamond’s value. Culture and tradition play an important role in color choices.

For example, warmer diamond tones are welcomed in India and Russia. At the same time, there is a strong preference for colorless stones in Asia. Museums worldwide are not ashamed to display royal regalia, where diamonds of various color grades are mixed. For example, in the Kremlin Armory, where Mr. Snowden is moonlighting as a janitor, cases are filled with piles of low-color diamonds.

Perceived diamond warmth

Unlike a solitaire ring that can be set with any color-grade diamond, a center stone for a three- or five-stone ring is recommended to be H-color or higher. Matching side stones to lower-colored diamonds is more complicated and can produce undesirable color amplification. Side stones are usually one color grade lower than a diamond in the center. Pave and micro-pave looks brighter with diamonds in the colorless diamonds. The main diamond in a ring with pave is recommended to be G or higher. 

Diamonds are graded upside down on a pure white background. A team of well-equipped diamond graders examines the diamond against a set of masters to determine the color. In a case they are split in their opinions, a vote is taken.
Diamond grading is more consistent today due to technological advances such as the use of colorimeters.
Nevertheless, the grading process is highly subjective. Diamond color is perceived differently from various angles. Cut, proportions, brilliance, and dispersion affect color perception. Old European cuts, step-cut diamonds, stones with lower depth face whiter than their grade suggests.
Once, we cut a single piece of rough into a pair of diamonds, each getting a different color grade. It took much effort to convince GIA to reconsider their decision.
The passing of time can affect the grade. When old stones are re-certified, they often get a slightly higher color grade because grading standards were more relaxed in the past.

A D-colored diamond is a freak of nature utterly void of any trace color. These albinos are prized because of their scarcity, not beauty. In fact, D-colored diamonds are unnaturally bright and look artificial.
A long time ago, a pure white stone was most likely a diamond because the only simulants were yellowish zircon or topaz.
Throughout history, a D-colored diamond, Mussolini’s briefcase, The Antikythera gizmo, and other artifacts are deemed valuable simply because they are rarities, not because they are exceptionally attractive. D-colored diamond can be a prized possession for a collector but not a bride. Setting it into an engagement ring is a waste.

Even professionals (with rare exceptions) cannot eyeball the difference between adjacent color grades. Color perception is highly subjective. It varies from person to person. Lighting conditions, the angle at which the stone is viewed, and cut variations affect the stone’s appearance. Most consumers cannot distinguish within 1-2 color grades even when diamonds are next to each other. Telling the difference when the stone is worn in the ring on a finger is impossible, especially when the ring is not regularly cleaned.

D is the top color grade, but it’s not practical and too expensive for most people.
We agree with Tiffany’s (de-facto bridal authority) that all diamonds I- and better are perfectly white and do not have a yellow tint. The only difference is how bright they are.
D-E colors are “vanity” grade. They are used mainly in high-end jewelry, which demands the finest material without concern of the cost.
F-G colors are “premium” and widely used in fine jewelry.
H-I is a “practical” choice for a reasonable price without sacrificing diamond quality.
It is worth repeating: the difference between F-G and H-I grades is only in brightness. These stones are perfectly white and do not have a yellow tint.

A little “suntan” is not detrimental for antique diamonds such as Asschers or Antique cushions. It gives them sharpness and better depth perception for a rich, natural look. Even J to M diamond is worth consideration for an Asscher or an antique cushion. Some people even prefer lower colors in antique-cut diamonds claiming they look more natural. In our professional opinion, the sweet spot for an Asscher is in the H to J color range. The sweet spot for an Antique cushion is in the G to I range. Step-cuts and antique-cut diamonds tend to muzzle the color.

Diamonds beyond Z-grade are called “fancy.” Their value increases with the color strength. Diamonds occur naturally in almost every hue: red, green, pink, and blue. They are the rarest and command astronomical prices. Adding a gold mirror “reflector” to low-colored diamonds (U and below) can amplify their color into a valuable and distinct fancy yellow color. Brilliant cuts tend to amplify the color. That’s why most fancy-colored diamonds are brilliant cuts such as radiants or modified cushions.

Store lighting cannot change the diamond color, but it can make it less obvious.
The full-spectrum lighting, which is equivalent to natural light, is best to view diamonds. Most jewelry stores are lit up with full-spectrum lights.
Even the natural daylight varies with seasons and weather conditions.

BMG stands for brown, milky, green in diamonds. Yellow is assumed to be natural diamond color, but it can brown and green as well. The diamond’s hue is not stated on the certificate unless it falls into the “fancy” color range.
Brownish or greenish hues can make diamonds below H-color look dark and unattractive. Such stones are undesirable and should be avoided.
The tint is impossible to detect by non-professionals, and even some pros struggle to see it.


What is Diamond Clarity?
Clarity is the presence of foreign matter called inclusions and blemishes in diamonds. Gemologists refer to inclusions as “identifying characteristics” and consider them a diamond’s unique “fingerprint” rather than a nuisance.

Diamond clarity is determined by the number, size, location, and type of inclusions:

  • Transparent or opaque crystals called pinpoints
  • Groups of pinpoints called clouds
  • Internal fractures called feathers
  • Internal graining (crystal growth twinning planes)

External blemishes: polishing lines, grain lines, scratches, chips, nicks, and “naturals” (part of the rough diamonds’ original surface).
Diamonds are graded by skilled professionals using natural or artificial light with a 10X loupe corrected for chromatic and spherical aberration or with a 10X binocular microscope equipped with dark-field illumination.

Clarity grades

The universally accepted GIA grading system has a total of eleven grades grouped into six categories:

Flawless (FL) Nothing is visible under 10x magnification. It’s a pure diamond crystal with positively no blemishes or inclusions. Flawless diamonds are generally not used in jewelry. They will most likely develop blemishes during the wear and drop to IF or even the VVS category.
Internally Flawless (IF) No inclusions visible under 10x magnification except minor blemishes. The blemishes can be repolished to bring the clarity grade to the Flawless. The surface grain lines cannot be repolished.
Very, Very Slightly Included (VVS1 and VVS2) Inclusions are so minor (often smaller than specks of dust) that it can take hours for a skilled gemologist to find them under 10x magnification. The difference between VVS1 and VVS2 grades is in the number and location of inclusions. VVS1 diamonds typically have no more than two inclusions on the periphery, while VVS2 inclusions can be closer to the center.
Very Slightly Included (VS1 and VS2) Minor inclusions requiring an effort to see the inclusions under 10x magnification. In step cuts, VS2 inclusions can be noticeable to a person with a sharp eye.
Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification.
Included (I1, I2, and I3) Inclusions are obvious under 10x magnification and, in I2 and below, almost certainly affecting diamond transparency and brilliance. Usually, these inclusions will be centrally located and noticed immediately when the diamond is examined. SI inclusions are usually evident when the stone is placed table-down on a white background but not face-up.

The SI clarity grade is an abbreviation for Slightly Included, according to the GIA clarity grading system. The SI-graded diamonds have readily and immediately visible inclusions under 10x  magnification. There are SI1 and SI2 subdivisions according to the severity of the inclusions and their visibility to the naked eye when carefully scrutinized.

Most SI1 brilliant-cut diamonds are eye-clean, but claims that all  SI1 diamonds are eye-clean are patently false. Another false claim is spotting inclusions within ideal-cut diamonds is harder because they are brighter and exhibit more sparkle.

All SI diamonds should be evaluated one by one, viewed from a normal distance of 9-12 inches while keeping in mind that the result depends on the observer’s vision. Even when incisions can be seen with an unaided eye, they are not necessarily glaringly obvious. Sometimes the inclusions can be barely made out only at a certain angle. This should be considered when evaluating the overall effect on the stone and reflected in the diamond’s price.

Occasionally some SI2 diamonds, despite being eye-clean, are borderline SI1s. This is rare and can be attributed to GIA personnel having a bad-hair day.

Diamonds with translucent, non-reflective inclusion or inclusions located at the girdle where prongs could cover them are desirable.
Prongs and bezels holding a stone are partially covering it. Strategically placing metal over the inclusion can hide it from view.
There are a few things to consider. Often the inclusion is too big to be covered. Also, some inclusions make a diamond fragile, so applying pressure with a prong during the setting can shatter the stone. And finally, sometimes, it is impossible to cover several inclusions without altering the prong’s position, which can negatively affect the jewel’s look.

An “eye-clean” diamond has no imperfections visible to the unaided eye. However, vision clarity, peripheral awareness, eye coordination, depth perception, focusing ability, and color vision vary from person to person. It makes a clear definition of “eye clean” impossible.

The traditional clarity grading system relies on 10x magnification to define the visibility of the inclusion.
What GIA should have done is to split SI stones into three or even four sub-categories. Unfortunately, they opted for just two, opening the door for creative and totally subjective opinions.
Regardless of their clarity grade, the eye-clean stones offer excellent value to the consumer.

There are only two clarity grades for most consumers: stones that look clean and those with something inside, real or imaginary.

The SI is a watershed grade for brilliant-cut diamonds making a “good SI” a sweet spot for bargain hunters.
For step-cuts, the VS2 grade is where eye-clean stones are mixed with those where inclusions stick out like a vegan at the steak dinner.

  • Knot is an exposed crystal breaking the diamond surface.
  • Abrasion is the damage from scraping or wearing away edges. Myriads of tiny chips blunt the intersections where facets meet.
  • Scratches are scores or marks on the surface caused by contact with another diamond.
  • Natural is a leftover section of the rough diamond skin that is left unpolished. Usually, naturals are on the girdle and are often mistaken for chips. Triangular marks called trigons help to identify them as the naturals.
  • Nick is a small chip on a girdle or facet. 
  • – White or transparent polish lines left on the surface after polishing can be easily removed, usually without losing weight. A “drag line” is a deep single polish line.
  • Polish marks are hazy areas on the surface caused by excessive heat during polishing.
  • Pit is a minute opening on the stone’s surface, usually mistaken for a pinpoint or a speck of dust.
  • Grain lines are wavy ripples caused by polishing the crystal’s zone of irregular growth.
  • Wavy skin is a transparent rippled texture from polishing a facet against the grain. 
  • Extra facets are usually added to remove a flaw close to the surface. Additional facets are usually located next to the girdle, where they are less visible.
  • Rough girdle is a grainy patch on a polished girdle left unpolished during faceting.

Leon Mege internal graining illustrationWhen external forces deep in the earth’s crust have caused a diamond crystal to grow unevenly, its internal structure is shifted, forming a linear or wavy pattern. The result is similar to heat waves visible when hot and cold air mix. Usually transparent, the graining can be reflective or opaque.

Internal graining cannot be removed because it is confined to the diamond interior. Relatively rare, internal graining usually has a minor impact on the overall look of a diamond. Still, internal graining significantly impacts the diamond value, especially when visible through the crown or can be seen with the naked eye.

Surface graining is an irregular diamond structure visible under extremely high magnification when lit up from an acute angle. It appears as faint transparent lines. Surface graining is stated in the comments section of a grading report because it is not an inclusion.

Unlike its brethren, internal graining, surface graining has zero effect on the diamond’s value. Moreover, it is so minor that the only clarity characteristic allowed in a Flawless diamond, according to GIA, is surface graining. In many cases, surface graining can be polished off without weight loss.

If we blow a diamond to the side of the Earth, the graining will be a mound only a few feet high on its surface. It is easier to spot surface graining than a hole inside a wheel of Parmesan. 

These are residual markings left behind when the rough crystal is cut by laser. They are minor blemishes on the diamond’s surface or inside the crystalline structure. A manufacturing remnant on the GIA report could also refer to faint burn marks caused by the excessive heat of the polishing wheel. Most of the time, they are not eye-visible and do not affect the diamond’s value.

carat size doesnt matter

Carat, Not Karat, Not Carrot

Diamonds are weighed on a carat scale (not to be confused with Karat, a unit of gold purity). The name “carat” is derived from the carob seed – a measuring unit used in the Middle Ages.

There are 100 points in one carat. For example, a half-carat diamond weighs 50/100’s of a carat or fifty points. The relationship between a diamond’s size and weight is not linear. A two-carat diamond is not twice the size of a one-carat diamond, only twice as heavy.

In the absence of the other three Cs – cut, clarity, and color, the increase in carat size is the most objective and definitive component of the 4Cs that makes the diamond rarer and more valuable.

Diamond’s Size in Millimeters

The size alone is not enough to determine a diamond’s value. We have to consider its cut, proportions, and polish. Even a large diamond has its value plummet when it is poorly cut.  When measuring small stones (melee or stones less than 0.05 carats in weight), we stop speaking of diamond weight and speak in terms of the diameter of a stone when referring to its size.

A single tiny stone is impossible to weigh. Jewelers weigh small diamonds in parcels to get an accurate reading. Center stones are usually weighed up to 100th of a carat. Recently, gem labs started issuing certificates that state a diamond weighs up to one-thousandth of a carat.

A round diamond’s diameter measured in millimeters can be used to estimate its weight in carats by using the following formula:

[Average diameter in mm] x [Depth in mm] x 0.0061




Diameter Carat
6.5 mm
1.00 ct
6.8 mm
1.25 ct
7.3 mm
1.50 ct
7.75 mm
1.75 ct
8.00 mm
2.00 ct
8.40 mm
2.25 ct
8.70 mm
2.50 ct
9.00 mm
2.75 ct
9.10 mm
3.00 ct
9.70 mm
3.50 ct
10.1 mm
4.00 ct
11.1 mm
5.00 ct
Diameter Carat
3.10 mm
0.12 ct
3.20 mm
0.13 ct
3.30 mm
0.14 ct
3.40 mm
0.15 ct
3.50 mm
0.16 ct
3.60 mm
0.17 ct
3.70 mm
0.18 ct
3.80 mm
0.20 ct
3.90 mm
0.22 ct
4.00 mm
0.25 ct
4.10 mm
0.27 ct
4.20 mm
0.28 ct
4.30 mm
0.30 ct
4.40 mm
0.31 ct
4.50 mm
0.34 ct
4.60 mm
0.40 ct
4.80 mm
0.44 ct
5.00 mm
0.49 ct
5.30 mm
0.55 ct
5.50 mm
0.63 ct
5.70 mm
0.70 ct
5.80 mm
0.75 ct
6.00 mm
0.82 ct
Diameter Carat
0.80 mm
0.0025 ct
1.00 mm
0.0050 ct
1.10 mm
0.0067 ct
1.20 mm
0.0090 ct
1.25 mm
0.010 ct
1.30 mm
0.012 ct
1.40 mm
0.013 ct
1.50 mm
0.014 ct
1.60 mm
0.016 ct
1.75 mm
0.019 ct
1.80 mm
0.02 ct
1.90 mm
0.025 ct
2.00 mm
0.03 ct
2.10 mm
0.035 ct
2.20 mm
0.04 ct
2.30 mm
0.045 ct
2.40 mm
0.05 ct
2.50 mm
0.06 ct
2.60 mm
0.07 ct
2.70 mm
0.08 ct
2.80 mm
0.09 ct
2.90 mm
0.10 ct
3.00 mm
0.11 ct

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