THE FOUR C’S

Normal Color Range (D-Z)

Most gem-quality diamonds have some hint of color. This is caused by trace chemicals in the earth where they formed over millions of years. The vast majority of diamonds are graded on the normal D-Z color scale, where D represents completely colorless and Z is notably yellow or brownish.

 

Fancy Colored Diamonds

A small percentage of diamonds with more color saturation than Z are called “Fancy Colored Diamonds,” or FCDs. Yellow or brown FCDs run from light to vivid, and FCDs may even be an altogether different color like pink or blue. All Fancy Colored Diamonds are graded using a different scale and approach than diamonds in the normal D-Z range.

 

Grading Color

Diamonds in the normal D-Z range are graded face-down, viewed through the side of the pavilion. This is because shape and cut quality both influence how light gets in and out of the diamond. Grading face-down allows for a neutral assessment of body color. The descending grades from D to Z are very gradual.

 

Did You Know?

The result of face-down grading is the fact that several diamonds of same-grade can appear different colors when viewed face-up. This can be influenced by several factors, including the following:

  • Laboratory Standards: Different laboratories have slightly different standards for color. Please see our page on “Labs We Use and Why” for more information. [link to 4.1]
  • Shape: Brilliant cutting styles return light to the viewer more efficiently than step cuts, so a round brilliant may show less apparent color face-up than an emerald or Asscher of the same grade.
  • Fluorescence: A diamond in the near-colorless or faint yellow range may have its face-up color reduced by medium or stronger blue-fluorescence. This is only seen on a case-by-case basis.
  • Cut-Quality: A diamond cut with the critical angles and precision needed for highest performance have shorter ray-paths reducing their face-up color; in some cases by multiple grades.

 

 

Top Cut Quality

The finest cut round brilliants often face up with less color than the laboratory color grade they were assigned, which was determined face-down. Why? Because light gets in and out of the diamond faster, on shorter ray-paths. This is the opposite of poor cutting, where critical angles are missed and light rays either escape through the pavilion or make multiple bounces before leaving, illuminating body tone. The more superior the cut quality the less color is seen face-up.

 

Discount Color

Diamonds in many chain stores, malls and discount outlets frequently have more tint for their grade than diamonds sent to stricter labs and/or hand-selected by our gemologists. This can give casual shoppers a negative first impression about certain colors. At Continental we can frequently reverse those impressions: In our experience diamonds cut for high performance have critical angles and precision-cutting which permits light to get in and out with greater intensity. Such diamonds appear more colorless than their laboratory grade. In fact, in hundreds of showroom viewings buyers are shocked when we don’t disclose color and they choose a “favorite” diamond several color grades below their previously imagined threshold due to its remarkable face-up appearance. This kind of determination cannot be made from a lab-report. It requires experienced gemological analysis and rejection of many diamonds to select a few.

 

Continental Diamond and Color

At Continental we are your advocate: We select diamonds for a specific balance of qualities. When it comes to color this includes an analysis of fluorescence, special attention to shape and cut-quality, the grade given by the laboratory and hundreds of other details inspected by our gemologists. While we promote laboratory certification a simple lab report cannot possibly communicate the complex and variable criteria which relates to the specifics of each diamond. To this end we are committed to providing clear and transparent education and explanation which eloquently covers the Four Cs and much more.

What Does Cut Mean?

The cut of a diamond refers to everything man has done in the process of converting it from a piece of rough, natural diamond material into a finished gemstone capable of the beautiful brightness and sparkle which makes diamonds the most popular of all precious gems. The details of cut include shape, make, angles, proportions, optical precision, weight ratio, facet symmetry and final polish. These specifics all combine to determine how the diamond will appear as it travels through the world’s many lighting conditions.

 

Most Important. Least Discussed.

Although cut is the most important component for diamond beauty, it’s typically discussed far less than color and clarity in most places. One reason is that color and clarity grading are easily learned by new sales professionals. But understanding the many details of cut requires a stronger commitment, as well as foundations in geometry and physics. It’s worth noting that most diamonds are cut to average quality and in-depth discussions about cut would reveal that lack of quality in average stores. The fact that many grading labs include little or no information about cut only underscores the resistance to cut education felt in commercial markets.

 

Did You Know?

Diamonds in the top few percent of the world’s cut actually improve in the other Cs: They appear larger for their carat weight, face up more colorless and clarity characteristics can be less visible. Most importantly, they explode with dazzling whiteness and rainbow colors, even away from jewelry store lighting where most diamonds go dark.

  • Top Cut Helps Size Appearance: A diamond cut for the highest level of visual performance appears larger than diamonds of average cut quality because they are bright all the way from edge-to-edge, not just bright in the center.
  • Top Cut Helps Color: A diamond cut with the critical angles and precision needed for highest performance has shorter ray-paths reducing face-up color; in some cases by multiple grades.
  • Top Cut Helps Clarity: A diamond planned and cut for highest performance boasts superior brightness and scintillation, even when removed from jewelry store lighting, which helps to “mask” inclusions.
  • Laboratory Standards: Different laboratories have radically different standards for cut. Please see our page on “Labs We Use and Why” for more information.
  • Shape: Brilliant and mixed shapes like round brilliant, princess and cushion, have a different “flavor” than step cuts such as emerald and asscher.

 

Soft Grading

Laboratory cut grades are famously softer than color and clarity. For example, approximately 85% of all round brilliant diamonds will be classified as “Excellent” or “Very Good” at most grading laboratories. This means it’s largely up to us at Continental to select only the best-cut diamonds to pass on to our clients.

 

Continental Diamond and Cut Quality

At Continental we are your advocate: We hand-select diamonds for a specific balance of qualities. When it comes to cut quality this includes partnering directly with the most boutique and specialized cutting operations in the world to bring the very best to our clients. In hundreds of showroom viewings buyers are shocked when we show them the incredible difference cut quality can make in two diamonds that are otherwise the same. This kind of determination cannot be made from a lab-report. It requires experienced gemological analysis and rejection of many diamonds to select a few. While we promote laboratory certification [link to 4.1] a simple lab report cannot possibly communicate the complex and variable criteria which relates to the specifics of each diamond. To this end we are committed to providing clear and transparent education and explanation which eloquently covers the Four Cs and much more.

Cut is absolutely, unarguably the most important C for diamond beauty. It is also the most difficult to understand.

Diamonds in the top few percent of the world’s cut actually improve in the other Cs: They appear larger for their carat weight, face up more colorless and clarity characteristics can be less visible. Most importantly, they explode with dazzling whiteness and rainbow colors, even away from jewelry store lighting where most diamonds go dark. Even average cut quality makes a diamond flash and sparkle in bright lighting, though it will not enjoy benefits to the other Cs. Poor cut quality may look attractive under bright lights but in normal lighting can make a diamond appear small, tinted and lifeless.

 

Common Cut Standards

Despite its preeminent importance cut is the least discussed C in most markets. Why? One reason is that color and clarity grading are easily learned, but understanding light performance within diamonds requires some geometry and physics. Some professionals seek education but the vast majority of workday salespeople are not trained and do not pursue it. It’s worth noting that most diamonds are cut to average quality and in-depth discussions about cut would reveal that lack of quality in average stores. The fact that many grading labs include little or no information about cut only underscores the resistance to cut education felt in commercial markets.

 

AGS and GIA Cut Standards

The American Gem Society (AGS) and Gemological Institute of America (GIA) are the leaders at enforcing standards for cut performance (although neither grades cut precision).

The American Gem Society (AGS) boasts the only cut grading system recognized by the science community. Published bySPIE, the International Society for Optical Engineering, theirs is a diamond-specific metric which evaluates angular spectrum in three-dimensions and takes different distances and tilt into account. Fewer than 1 in 20 round diamonds are capable of earning the AGS Ideal grade and this number falls to 1 in 100 for princess cuts. Only 2% of diamonds are sent to the AGS for grading, so diamonds graded there are rare.

The GIA employs a two-dimensional cut metric for round diamonds. Approximately the best 15% of round diamonds will earn the top grade in the GIA system, although some fall in a steep/deep area that does not result in high performance. The GIA does not yet grade cut fancy shapes.

Diamonds And Nature

Nearly all diamonds have natural characteristics that formed within the rough crystal over millions of years of growth. Most are microscopic and need magnification to detect. Others may be visible to the naked eye.

 

Absolutely Unique

What is certain is that no two diamonds are the same. Each is like a snowflake; never repeated in nature. In fact, one sure ways to identify your diamond is to memorize where a primary inclusion lies. Depending on the diamond’s clarity specifics (and your eyesight) it may be possible with no aid, or it may require a magnifying device. Either way, every diamond’s inclusions tell a special story that is absolutely unique.

 

Blemishes and Inclusions

Clarity characteristics are separated into two broad categories: Blemishes, which are external, and Inclusions, which are internal. The laboratory grading report will list all characteristics, in order of importance, with the primary characteristic(s) “setting” the clarity grade.

 

Grading Clarity

The clarity grade is determined by examining the diamond face-up at 10X magnification in neutral lighting. Five factors are considered: These include the size, number, position, visibility and type of characteristics visible at 10X magnification. If the implications are minute or minor the clarity grade is likely to be high. If the implications are noticeable or obvious the clarity grade will be lower.

  • When strictly graded, FL and IF indicate the diamond is Flawless, or Internally Flawless; revealing no inclusions at this magnification.
  • VVS1 and VVS2 indicate Very Very Slight inclusions; meaning that only minute characteristics were detected.
  • VS1 and VS2 imply Very Slight inclusions; the grader saw only minor characteristics.
  • SI1 and SI2 grades indicate the diamond was Slightly Included; inclusions were notable under 10X magnification.
  • I1 means Included; characteristics were obvious to the grader when magnified.
  • The I2 and I3 grades are reserved for diamonds with extremely obvious inclusions and/or durability issues caused by the inclusion type.

 

Did You Know?

While diamonds are graded under 10X magnification they are not graded outside the ‘scope. This means that several diamonds of same-grade can appear differently to the naked eye. This is further influenced by several factors, including the following:

  • Laboratory Standards: Different laboratories have slightly different standards for clarity. Please see our page on “Labs We Use and Why” for more information. [link to 4.1]
  • Shape: Brilliant cutting styles have greater faceting complexity and less transparency, so a round brilliant may show inclusions less than an emerald or Asscher of the same grade.
  • Size and Number: An inclusion plot that looks “clean” may not correspond to a cleaner presentation, since a single grade-setting crystal may be more naked-eye visible than several smaller crystals which set the same clarity grade collectively.
  • Position and Visibility: A diamond with a dark central inclusion can present with far more naked-eye visibility than one with a transparent inclusion under a girdle facet, yet both diamonds might have the same clarity grade.
  • Cut-Quality: A diamond cut with the critical angles and precision needed for highest performance boast superior brightness and scintillation, even when removed from jewelry store lighting, which helps to “mask” inclusions.

 

Top Cut Quality

A skilled diamond cutter can plan the “lay” of a grade-setting inclusion to reduce its face-up visibility. It may be impossible to omit a primary characteristic (and the resulting clarity grade) but a skilled cutter can orient the rough so that they become transparent or less visible. This is particularly true for SI1, SI2 and I1 clarity grades.

 

Discount Clarity

Diamonds in many chain stores, malls and discount outlets frequently have more obvious inclusions for their grade than diamonds sent to stricter labs. This can give casual shoppers a negative first impression about certain clarity grades. At Continental we can frequently reverse those impressions: In our experience well-planned diamonds can break conventional barriers. In hundreds of showroom viewings buyers are shocked when we don’t disclose clarity and they select a “favorite” diamond that is revealed to be lower than their previously imagined clarity threshold. This kind of determination cannot be made from a lab-report. It requires experienced gemological analysis and rejection of many diamonds to select a few.

 

Continental Diamond and Clarity

At Continental we are your advocate: We hand-select diamonds for a specific balance of qualities. When it comes to clarity this includes up-front analysis of inclusion type/durability, special attention to naked eye visibility and diamond design, the grade given by the laboratory and hundreds of other details inspected by our gemologists. While we promote laboratory certification a simple lab report cannot possibly communicate the complex and variable criteria which relates to the specifics of each diamond. To this end we are committed to providing clear and transparent education and explanation which eloquently covers the Four Cs and much more.

Carats and Points

Diamond weight is expressed in carats. One carat is equal to 200 milligrams. Carats are further divided into 100 “points” so that a 0.90 carat diamond may be called a 90-pointer, a 0.88 carat diamond an 88-pointer and so-on. The word ‘carat’ has roots in ancient times, when diamonds were first traded compared against carob beans.

 

Did You Know?

Carat weight is NOT size. Diamonds of the same carat weight have different vertical spreads, determined by average girdle diameter.

 

Shallow and Deep Diamonds

The goal of diamond manufacturers is to maximize carat weight from each piece of rough, since carat weight sets price more than any other factor. As a result, many diamonds are cut shallow or deep, which can negatively influence appearance. Be sure your diamond is proportionate for its carat weight.

 

Proportionate Diamonds

Diamonds cut for the highest level of visual performance are proportionate, with critical angles and precision-cutting that promotes the best brightness, dispersion and scintillation. Such high performing diamonds appear larger than diamonds of normal cut quality because they have edge-to-edge brightness, not just a bright center.

 

The example on the right above, with a spread of 6.30 millimeters was cut slightly “deep” and will look smaller than a proportionate one-carat diamond, spreading closer to 6.50 mm. The example on the left above has greater spread, but was cut “shallow” and will lack the critical angles necessary for performance, reducing edge-to-edge brightness and potentially increasing dark zones.

 

Continental Diamond and Carat Weight

At Continental we are your advocate: We select diamonds for a specific balance of qualities. This includes spread appropriate for carat weight, and hundreds of other details inspected by our onsite gemologists. While we promote laboratory certification a simple lab report cannot possibly communicate the complex and variable criteria which relates to the specifics of each diamond. To this end we are committed to providing clear and transparent education and explanation which eloquently covers the Four Cs and much more.