Diamond Education

Learn About 4C’s

Cut, Color, Clarity, Carat

Cut

Cut is the basic facet arrangement of a diamond. It is the only attribute in a diamond a human can modify unlike color and clarity as it decides how a light ray will enter and get refracted from a diamond.

The finer the cut, the brilliant is the diamond’s shine and the more is its value. Hence it is one of the most important criteria for judging a diamond’s value as it directly affects its appearance.

Brilliance, Polish and Symmetry of a Diamond

Cut of a diamond affects its Brilliance (reflection of light), whereas Polish (smoothness of facets) and Symmetry (alignment of facets) affect the sparkle of a diamond. A poor polish can make a diamond look dull and a poor symmetry can misdirect the light reducing the sparkle.

Types of Cut

There are three types of cuts as shown in the figure:

Shallow Cut

In which light refracts away through the bottom.

Ideal Cut

In which light gets reflected through the top producing maximum brilliance.

Deep Cut

In which light refracts away through the sides.

GIA Cut Grading

Diamond cuts are graded on the following scale established by the Gemological Institute of America (GIA):

• Excellent Cut: The rarest cut grade of all, Excellent cut reflects maximum light entering the diamond and thus shines with optimum brilliance.

• Very Good Cut: Very Good cut grade may cost less than the Excellent cut, but it is equally beautiful and brilliant.

• Good Cut: Good cut grade of a diamond helps reflect light to obtain a good amount of brilliance, though not equal to the Excellent or Very Good cut. Thus it demands a much lesser price.

• Fair Cut: Being not as brilliant as a Good cut, Fair cut grade quality diamonds refract less amount of light, but make a better choice than Poor cut diamonds.

If you want to buy a diamond with utmost brilliance, then Excellent cut grade is a suitable option with good polish and symmetry.

However, if the budget restricts you, a diamond with good polish and symmetry and excellent or very good cut can be chosen in G-H color and SI1 or SI2 clarity.

 

Clarity

Clarity determines the purity of a diamond. Sometimes due to the retention of carbon, a diamond may appear impure. Such natural impurities found in diamonds are called Inclusions. The lesser the inclusions, the higher is the Clarity of the diamond which makes it appear eye-clean, pure and therefore more expensive.

Internally, inclusions may occur in the form of tiny spots, fractures, feathers etc., while externally they may appear as scratches and fissures. Sometimes an inclusion does not affect a diamond’s brilliance or gets easily hidden by its setting. Diamonds with least or no inclusions are of the highest quality and therefore the most sought after

GIA Clarity Grading

The Gemological Institute of America (GIA) has various grading scales to judge the purity of a diamond. They are:

• FL (Flawless) – Diamonds that are absolutely flawless i.e., no inclusions or blemishes are seen to a skilled grader using 10x magnification.

• IF (Internally Flawless) -Diamonds those have no inclusions, but slight blemishes appear externally to a skilled grader using 10x magnification.

• VVS1, VVS2 (Very, Very Slightly Included) – Most sought after diamonds with very-very small inclusions internally even difficult for a skilled grader to identify under 10x magnification. They are highly priced as these inclusions are never visible to naked eye.

• VS1, VS2(Very Slightly Included) – Diamonds with very slight inclusions clearly visible to a skilled grader using 10x magnification. VS1 and VS2 diamonds are very affordable.

• SI1, SI2 (Slightly Included) – Diamonds with slight inclusions noticeable to a skilled grader using 10x magnification.

• I1, I2 and I3 (Included) – Diamonds with inclusions obviously visible under 10x magnification and may effect transparency and brilliance.

B2C Jewels’ Ideal Clarity Grade

If you prefer a diamond with no inclusions visible to the naked eye, then VS1 or VS2 would be an ideal clarity match for you. However, diamonds with SI1 or SI2 clarity are also a neat choice and are generally referred to as Eye-Clean Diamonds.

What is the definition of Eye-Clean?

We define an eye-clean diamond as no inclusions seen in the face-up orientation at a distance of 25cm, under normal lighting, when viewed by a gemologist with 20/20 vision.

Although there is not an industry standard definition of an eye-clean diamond, our definition is derived from three factors: distance, lighting and vision. For a person with normal 20/20 vision, the ‘near point’, defined as the closest point that an item can be viewed by the eye without appearing blurry under normal lighting, is 25cm. By incorporating an expectation of ‘near point’ (25cm) viewing, normal lighting, and 20/20 vision our definition of ‘eye-clean’ gives a realistic baseline for all diamonds – whether loose or in a jewelry setting.

 

Color

Color is the next most important aspect of a diamond. When we talk about color of a diamond, we generally refer to the presence or rather absence of color in it. Presence of color in a diamond is in the form of yellow or brownish tints. This diminishes its sparkle as it restricts maximum refraction of light. The value and shine of a diamond increases as it moves towards colorless. The bigger the stone, the more obvious is the presence of color in it. Fancy cuts such as pears, hearts and marquises tend to draw color which appears more pronounced at the points.

Types of Colors

Most diamonds sold in the retail trade run from near colorless to slightly yellow or brown, in the normal color range. Diamonds are also found in a variety of other colors such as black, grey, blue, green, yellow, brown, orange, pink and the rarest of all, red. Diamonds with distinct tints other than the normal colors are classified as Fancy colors. The term White Diamond is interchangeably used for colorless diamond. But in reality, the appearance of a White Diamond is very different from a colorless diamond as the former is not as clear as a colorless one.

Fluorescence of a Diamond

Fluorescence is the property which is seen in some diamonds when they are exposed to ultraviolet light. Therefore, it should not be a deterrent in buying a diamond because under most light conditions, fluorescence is not visible. Only a trained gemologist can detect the fluorescence and that too in ultra violet light. Presence of fluorescence can be graded as faint, inert, negligible, medium and strong or very strong, out of which the latter two are the better options which can make your diamond look even cleaner.

GIA Color Grading

Diamonds are graded on a color scale established by the Gemological Institute of America (GIA) which ranges from D (colorless) to Z. The GIA grades diamonds in the following color scale:

 

• D,E,F: Colorless

• G,H,I,J: Near Colorless

• K,L,M: Faint Yellow or Faint Brown

• N,O,P,Q,R: Very Light Yellow or Very Light Brown

• S to Z: Light Yellow or Light Brown

 

Metal and Color

The color of the metal in a mounting can either mask or enhance the color of the diamond.

• Yellow metal makes slightly yellow or brown diamonds appear more colorless, while darker yellows and browns look darker and richer in yellow gold setting. Warmer colored diamonds (K-Z) are particularly desirable when set in yellow gold.

• White metal makes slightly yellow or brown stones look duller (usually unpleasant), but on the other hand enhances the color of blue stones. Icy winter whites (D-J) look stunning in white gold or platinum.

B2C Jewels’ Ideal Color Grade

G – H grades with medium to no fluorescence are a perfect choice for those who prefer colorless stones but are constrained by their budget.

 

Carat

Weight of a diamond determines its carat. An increase in its carat weight indicates increase in its price as well. Higher carat weight also increases price per carat in large diamonds, i.e. the total price of four quarter carat diamonds would be considerably less than the price for a single 1 carat diamond of comparable quality, and total price of hundred point carat diamonds would be yet lesser than the total price of four quarter carat diamonds.

Measurement of a Diamond

Like many other gemstones, diamonds are also weighed in metric carats where 1 carat = 0.2 grams which is slightly more than 0.007 ounce avoirdupois (measurement used in grocery stores). Fraction of a carat can make a huge value difference, even in the case of smaller diamonds. That is why diamonds are weighed in a thousandth of a carat and rounded to the nearest hundredth point. Diamond range starts from a small point to more than 100 carat, but in regular diamond market people shop for diamonds ranging from 5 points to 3 carat.

While purchasing diamonds, people generally consider the total carat weight of all diamonds present in a jewelry piece and do not talk about the individual weight of each diamond. E.g. if a ring carries fifty 1 point diamonds or two quarter carat diamonds or a single half carat diamond, the total diamond weight is observed as half carat in all cases, however the prices may vary considerably, being the highest for a single half carat diamond.

Cullinan is the largest rough gem diamond ever discovered and it weighs around 3,106.75 carats, while Golden Jubilee Diamond weighing 545.67 carats is the largest polished diamond.

Diamond Relative Carat / Size Comparison

Carat is a measurement of weight, not size and so the overall diameter (mm) could differ slightly even though the carat weight is correct. Image is not to scale. Diamond pictures are shown for comparison purpose only. Actual size can vary depending on your screen resolution, monitor size, etc.

Loose diamonds can be weighed on a jeweler’s balance. However incase the diamond is mounted, the weight is estimated using the weight-estimation formula. Estimating weight in this fashion is less precise but enough to let appraisers make reasonable evaluations without demounting the diamonds.

 

Diamond Shape

Diamonds are natural crystals that come in large variety of shapes such as round, princess, heart, oval, marquise etc. The following information will help you to choose the right shaped diamond.

Brilliant Round

A classic diamond to most people is a round gem of sparkling white brilliance with a kaleidoscope of dazzling facets. This shape has set the standard for all other diamond shapes and accounts for more than 75% of diamonds sold today.

Princess

Princess is a brilliant square diamond with sharp, uncut corners and pavilion facets that are wide at the culet and narrowed towards the girdle. Princess is one of the most popular cuts in the United States after the brilliant round.

Oval

It is similar to the round diamond in sparkle and brilliance. A perfectly symmetrical oval diamond is very popular as a center diamond piece for engagement rings and among women with small hands or short fingers as they make fingers appear slender.

Marquise

Marquise is a boat-shaped modified round diamond with pointed ends. Its elongated shape makes fingers look long and slender. It is very essential to choose a diamond with perfect facet alignment to retain its brilliance.

Heart

This ultimate symbol of romance essentially shaped like a heart, is an ultimate gift for Valentine’s Day. A very flat diamond appears big, but lacks brilliance, while an overly deep diamond’s brilliance looks good but the diamond looks smaller than the ideal.

Emerald

Emerald diamond is a step-cut diamond having a row of elongated facets (usually 48 to 50) that resembles a stair case. The flat planes of the outside edges allow for a variety of side stone shapes, except for trillions that don’t blend well with emerald.

Radiant

This square or rectangular shape diamond has 70 facets that maximize the effect of its color refraction. Avoid radiant diamonds which are less deep or too deep and ones that lack life.

Cushion

A cushion cut is square or rectangular in shape with rounded corners and 58 brilliant facets that resemble a pillow shape, hence the name. Cushion cut diamonds are very popular in matching pairs.

Asscher

The Asscher cut is a variation of the Emerald cut except that it is square. It is characterized by a small table and large steps. Since it is cut in the same manner as the Emerald, one has to be very careful while selecting and paying for the right diamond.

 

Diamond Certification

Many gemological laboratories give a report of their evaluation of a diamond that influences the price of the diamond. Certificates are minute details and characteristics of a diamond that are not visible to the naked eye. For a buyer, diamond certificate is an assurance that the product bought is genuine and is worth the amount paid.

Sample GIA Diamond Grading Report View

Why need a Diamond Certificate?

The Gemological Institute of America (GIA) has various grading scales to judge the purity of a diamond. They are:

A certificate assures a diamond buyer of the quality and authenticity of the diamond.

As most diamond buyers are not experts, a certificate allows an objective comparison.

In addition, should you resell your gem, the certificate will provide the stamp of authenticity you’ll need to get a fair price.

Which Gemological Labs are reliable?

 

1. The Gemological Institute of America (GIA):

GIA is the most reputed and reliable laboratory for gem evaluation as it has developed the first internationally accepted Diamond Grading System and set the standard for diamond quality documentation around the world. The GIA Gem Trade Laboratory issues these reports on a majority of high quality diamonds over one carat in size.

Details in a GIA Diamond Certificate:

Date: Located at the top most left corner of the report, it shows the date on which the Diamond was examined and issued by GIA.

GIA Report Number: Unique GIA identification number.

Laser Inscription Registry: At the request of the customer, the diamond is micro laser inscribed with its unique GIA Report Number.

Shape And Cutting Style: Description of the outline of the diamond (shape) and the pattern of the facet arrangement (cutting style).

Measurements: The dimensions of the diamond listed as minimum diameter – maximum diameter x depth for round diamonds and length x width x depth for fancy shape diamonds.

Carat Weight: The weight of the diamond given in carats

Color Grade: The assessment of absence of color from colorless to light yellow or brown when compared to GIA Master Color Comparison Diamonds.

Clarity Grade: The assessment of inclusions (internal characteristics) and blemishes (external characteristics) visible under 10x magnifiers.

Clarity Characteristics: The description of any internal and/or external characteristics, if present.

Cut Grade: A grading for the cut of diamond ranging from excellent to fair.

Polish: The overall condition or smoothness of the diamond’s surface.

Symmetry: Exactness of the diamond’s outline and the shape, placement and alignment of its facets.

Fluorescence: The strength and the color of the diamond when viewed under long-wave ultra violet light.

Comments: The additional identifying characteristics or features that are otherwise not represented on the report.

GIA Color and Clarity Scales: The grading scale graphics of GIA Clarity and Color with the relative positions of color and inclusions in the GIA Diamond Grading System.

Proportion Diagram: A Graphical profile representation with the diamond’s actual proportions.

Security Features: A suite of security components including a hologram, security screen and microprint lines in addition to several other proprietary security features to ensure integrity.

 

2. American Gem Society (AGS):

AGS laboratories serve an international clientele of retail jewelers, wholesale suppliers, diamond cutters and manufacturers. AGS’ Diamond Quality Document or DQD provides information on all 4 C’s of diamond grading. Ratings are given on a scale of 0 to 10.

AGS Clarity Grade: This scale ranges from 0 to 10, 0 being the rarest and most desirable and 10 the least desirable. An AGS Grade of 0, with no comments about the finish of the diamond in the comments section of the document, is equivalent to the GIA Grade of Flawless. An AGS Grade of 0 with comment(s) referring to the finish or surface characteristics is equivalent to the GIA Grade of Internally Flawless.

AGS Color Grade: The AGS Color Scale is based on the original colorimeter invented by Robert M. Shipley Jr. The old AGS scale had only eleven color grades 0 to10, which was then updated with point increments. This update provided three things: more accuracy, more grades (21 instead of 11) and exact cross-reference to the GIA letter scale.

AGS Plot: The plot, including the crown and pavilion views, is printed directly on the DQD. For Round diamonds, the AGS laboratories are able to print the crown view with the accurate table diameter percentage.

 

3. International Gemological Institute (IGI):

Over 250 staff members at IGI issue over 400,000 gem reports annually. IGI has three distinct products: Diamond Report, Identification Report and Information Appraisal Report.

 

4. European Gemological Laboratory (EGL):

EGL has defined criteria and standard procedures for accuracy and consistency in its Diamond Certificate and Diamond Consultation. EGL Certificates are recognized worldwide. Their main clients are diamond wholesalers, dealers, manufacturers, and craftsmen.