The 4Cs


When shopping for an engagement ring you’ll hear words like cut, clarity, carat weight, color, the 4Cs, fire, brilliance, prong set, pave, and many others.  Having a basic understanding of not only diamond terminology, but engagement ring terminology as well will benefit you greatly as you begin your search.

Here are some diamond and engagement ring terms you should familiarize yourself with before you begin your engagement ring search.

Diamond Terminology

Blemish – a clarity characteristic confined to the surface of a polished diamond

Brilliant cut – a cutting style in which triangular and kite shaped facets spread out from the diamond’s center toward the girdle

Brilliance – the brightness that stems from the center of the diamond.  Brilliance occurs when light enters through the table, reaches the pavilion facets, and is reflected back through the table.

4Cs Cut, Color, Clarity, Carat weight

Carat (ct) – standard term used for the weight of a diamond

Clarity – absence of internal inclusions and external blemishes

Color – absence of color in a diamond

Cut – the proportions and finish of a polished diamond

Clarity characteristics – internal or external feature of a diamond that helps determine the quality and establish its identity

Crown – the upper portion of the diamond above the girdle

Culet – a facet sometimes added to the bottom of the pavilion to protect the tip

Eye clean – a term used to describe a diamond with no blemishes or inclusions that can be seen with the unaided eye

Face-up (aka table up) – a position where the diamond’s crown and table are pointed towards the viewer

Face-down (aka table down) – a position where the diamond’s pavilion is pointed towards the viewer

Facet – a smooth flat plane on the surface of a diamond.  Facets allow light to enter a diamond and reflect off its surface at different angles creating color and light.

Fancy cut– any diamond shape other than a round

Fire – the flashes of colors in a polished diamond

Fluorescence – the emission of visible light by a diamond when it is exposed to ultraviolet radiation

Girdle – the outer edge or outline of the diamond’s shape

Inclusion – a clarity characteristic totally enclosed in a polished diamond or extending into it from the surface

Pavilion – the lower portion of a diamond below the girdle

Plot (aka diamond certificate) – a map of a diamond’s inclusions, blemishes, and facet arrangements

Point (pt) – a unit of measurement used to describe the weight of a diamond

Proportions – the angles and relative measurements of a polished diamond and the relationship between them

Scintillation – the flashes of light and dark areas you see when the diamond, light, or observer moves

Shape – the face-up outline of a diamond

Shape appeal (aka “eye-pleasing”) – a diamonds overall appearance in relation to others of the same size, shape, and cutting style

Scintillation – the flashes of light and dark areas you see when the diamond, light, or observer moves.

Engagement Ring Terminology

Setting Styles

A Prong setting (aka claw setting) is the most common type of setting for solitaire diamond rings.   The diamond is placed in a metal head or basket and it is secured using 3-8 prongs.  The shapes of prongs vary in style and may even contain small accent diamonds.

Advantages – allows more diamond to show than any other style, is secure, easy to clean, and is quick to set.

Disadvantages – does not provide a smooth surface and the prongs can catch on clothing or hair and the girdle area of the diamond is left exposed.

A Channel setting is very popular for not only engagement rings, but wedding bands as well.  The diamonds are placed in a row and are “suspended” between two continuous pieces of metal on the top and bottom with no metal between each stone.   It provides a smooth surface across the ring and protects the girdle of the diamonds; which makes it a great setting choice for someone that is very active or uses their hands a great deal.  The diamonds used for a wedding band are usually all the same size, but may differ in size for engagement rings graduating from larger to smaller down the shank.

Advantages – protects the girdle area of the diamonds and provides for a smooth surface.

Disadvantages – more time consuming and costly to set than a prong setting because all stones must be evenly spaced and secure.

A Pave setting (aka bead setting) contains small round brilliant cut diamonds that are set level with the surface of the ring.  Tiny holes are made in the setting and once the diamond is placed into the hole the surrounding metal is raised to form tiny beads or prongs that will hold the diamond in place.  Pave adds brilliance to the ring and creates the illusion of a larger center stone.  Pave settings are commonly designed using white gold or platinum to minimize the appearance of metal.  Pave settings are quite durable, but aren’t for everyone.  Pave settings also require a little more cleaning and care than prong, channel, and bezel settings.

Advantages – provides great protection for the girdle and pavilion, accentuates the center stone and can make it appear larger than a prong setting, and it allows for an uninterrupted design.

Disadvantages – it doesn’t provide for a smooth surface like a channel setting or channel setting.

Metal Choices

Platinum is rare, pure and known for its durability.  Platinum is 95% pure and will not fade or tarnish keeping its rich white color for a lifetime.  With everyday wear platinum will develop a patina overtime.  Platinum is extremely strong and will hold precious stones firmly and securely in place.  Platinum will scratch, but unlike other metals no metal is lost it is just displaced.  Platinum is hypoallergenic and is a great choice for someone with sensitive skin.

Palladium is part of the platinum family and has a grayish white tone.  It is 10% stronger than platinum and consists of 95% palladium and 5% ruthenium which makes it more scratch resistant than platinum.   Palladium is also a hypoallergenic metal.

White Gold, available in 10kt, 14kt or 18kt, is pure gold alloyed with palladium, zinc or nickel.  The alloys in white gold make it stronger than yellow gold.  To mask the slightly yellowish tone in white gold it is rhodium plated giving it a bright white finish.

Yellow Gold, available in 10kt, 14kt or 18kt, is pure gold alloyed with copper and silver.  Its color looks great with all skin tones and gemstones.

Rose Gold, available in 10kt, 14kt or 18kt, is pure gold alloyed with copper.  Rose Gold has a soft tone that compliments the skin’s natural coloring.  Rose Gold comes in a variety of shades from reddish to a soft pink.  Rose Gold is not recommended for individuals with metal allergies because of its copper alloy.

Shop all Since 1910 diamonds and engagement rings to find the perfect one for you

Buying a diamond should be a great experience and one that is not confusing or overwhelming.  Like any other large purchase you make, education and knowledge is key.  Before purchasing your diamond make sure you have at least a basic understanding of the 4Cs, diamond shapes, diamond terminology, and what to look for on a diamond grading report.  This will prepare you to ask the right questions and will give you the confidence that the decision you make is the right one for you.

The 4Cs of Diamonds: Cut, Clarity, Carat Weight, Color

Diamond Cut

Of the 4Cs, Gemologists believe that cut has the greatest influence on a diamond’s beauty.  Cut is the factor that determines the diamond’s fire, sparkle, and brilliance.   Diamonds have a unique ability to effectively manipulate light.  This unique quality can only be realized with an extremely high level of accuracy during the cutting and polishing process.  Where nature dictates the uniqueness of color and clarity, humans affect the cut.  While cutting diamond rough, cutters must not only consider the proportions of a diamond, but also the craftsmanship of overall symmetry and polish as well.

A diamond’s brilliance comes from light entering the crown and reflecting from one facet to another and returning back out the crown.  A diamond that is cut too shallow or too deep will not reflect light properly and the diamond will not be as brilliant as a diamond with an excellent cut.

Diamond Clarity

Clarity refers to the absence of clarity characteristics in the diamond. The GIA clarity scale consists of 11 grades ranging from flawless to included.  When determining a diamond’s clarity grade, GIA considers the size, nature, color, position, and quantity of clarity characteristics under 10x magnification.  The lesser the number of inclusions or blemishes a diamond has the higher clarity grade it will receive.  A diamond with no inclusions using 10x magnification will be considered flawless and is very rare and more costly.


An inclusion is a clarity characteristic either totally enclosed in a polished diamond, reaching or extending into it from the surface, or one that is caused by treatments or the cutting process.  Note – Inclusions caused by treatments or the cutting process may not always be documented on the diamond certificate.


A blemish or external clarity characteristic is on the surface of the diamond only and can be caused by wear, the cutting process, or may be a result of the diamond’s crystal structure.   Blemishes play a lesser role than inclusions do when determining the clarity grade, but may affect the polish grade.

GIA Clarity Grades

FLFlawless – no blemishes or inclusions under 10x magnification.

IFInternally flawless – no inclusions and only very minor surface blemishes.

VVS1 and VVS2 Very, very slightly included – very, very small microscopic inclusions extremely difficult to see under 10x magnification.

VS1Very slightly included – very small microscopic inclusions difficult to see under 10x magnification.

VS2Very slightly included – very small inclusions somewhat easy to see under 10x magnification.  These diamonds represent a good value to someone looking for a high quality diamond, as the very small imperfections do not affect the beauty of the diamond.

SI1Slightly included – small inclusions that are easy to see under 10x magnification. This clarity is an excellent choice for someone looking to stay within a budget, but wants a diamond that will look as good as a higher clarity diamond except when viewed under magnification.

SI2 – Slightly included – small inclusions that are visible under 10x magnification. Depending on their location within the diamond, they may sometimes be visible to the unaided eye without magnification.  SI2 diamonds are attractively priced and typically no visible difference can be seen without magnification.  If you are interested in an SI2 diamond and would like us to personally verify if it is eye-clean, please give us a call at 1-800-979-1910.

I1* and I2Included – imperfect with inclusions that are obvious to the unaided eye and may affect the diamond’s durability.

I3*Included – imperfect with inclusions that are extremely obvious to the unaided eye and pose a definite threat to the diamond’s durability.

*At Since1910.com, we do not sell I1, I2, and I3 clarity diamonds.

Diamond Carat Weight

Carat weight refers to the size of the diamond.  Carat is the standard term used for the weight of a diamond and received its name from the seed of a carob tree.  The carob seeds were used by early diamond traders on scales as units of weight for small amounts of diamonds because of their consistent size.  The weight of the carob seed was 200 milligrams and the weight of a carat is exactly 200 milligrams or as it is know today, 0.2 grams

Many believe that the term carat represents the size of the diamond however; carat represents the weight of a diamond.  One carat is divided into 100 points.  So, for example, a quarter carat or 25 point diamond weights .25 carats (cts).   Diamonds weighing over one carat are expressed as carats and decimals.   They are measured to the hundred thousandths of a carat and rounded to a hundredth of a carat.   For example, a 1.25 stone would be described as one point twenty five carats.

The cost of a diamond is not measured in weight alone.   Several diamonds of the same weight can be priced considerable different.  When calculating the cost of any diamond, clarity, cut, and color are major factors as well.

Diamond Color

Color refers to the absence of color in the diamond.  Diamonds composed of pure carbon are colorless and extremely rare and costly.  Most diamonds contain nitrogen, boron, or hydrogen all of which impact color.  A majority of white diamonds sold on the market today contain traces of nitrogen, which causes slight shades of yellow or brown.  Small, subtle differences in color can make a substantial difference in a diamond’s value.

In a effort to eliminate confusion related to diamond color, the Gemological Institute of America (GIA) implemented the color grading system in the 1950s which is still being used industry wide today.   Diamonds are graded on a scale beginning with the letter D (colorless) and ending with Z (light yellow or brown).   When creating the new color scale GIA chose to start with the letter D as a means of starting over.  Prior to GIA implementing the D-Z scale, other systems all of which were inconsistent and inaccurate, already used the letters A-C, numbers 0-3, and the Roman numerals I-III.  It is important to note that diamonds at the end of the color range with a noticeable yellow tinge are not considered fancy yellow color diamonds.

Factors to Consider When Choosing a Diamond Color

  • When a diamond is well cut the diamond’s refraction and dispersion will often disguise certain degrees of color and may make a darker diamond appear whiter when viewed with the unaided eye (without magnification).
  • The size of the diamond will also affect the appearance of its color.  Color can easily be seen in larger diamonds as opposed to smaller diamonds.  Often times it is difficult to see color in diamonds under a 1/2 carat with the unaided eye.
  • The shape of the diamond will affect its color as well particularly step cut diamonds such as the Asscher and Emerald that have large open facets and do not display the brilliance of other cuts.  The center of these diamonds display a “window effect” where some of the color in the diamond can appear washed out and make it appear whiter then its actual color grade.  The shallower the cut of the diamond the more apparent this will be.

Diamond Shapes

Diamond shape is the basic outline of the diamond.   Here are some popular shapes sold today.

Round Brilliant is the most popular.  It consists of 56 to 58 facets and displays the most brilliance, fire, and scintillation of all diamond cuts on the market today.

Asscher is a stepped square cut also known as the modified square emerald cut.  It consists of 72 facets and resembles the shape of an octagon.

Cushion is not as brilliant as many of the more modern cuts, but has a classic romantic look that definitely stands out in a crowd.

Emerald is a cut that provides a very elegant classy look and is known for its long lines.  The pavilion is cut with large rectangular facets to create an open effect or optical appearance.

Heart is known as the most romantic of all shaped diamonds.  The heart consists of 59 facets and is essentially a pear cut with a cleft at the top.

Marquise resembles the shape of a football when viewed from above.  The marquise is bright, clear, and has a great deal of sparkle.

Oval is an adaptation of the round brilliant and usually looks larger than the round brilliant of the same carat weight.

Pear is half oval and half marquise.  The pear has 58 facets and displays the brilliance, fire, and sparkle of the round brilliant.

Princess is square shaped with uncut pointed corners.  The princess has 58 facets and is known for its brilliance, fire, and sparkle.

Radiant has 70 facets and has the brilliance and fire of the round brilliant.  The radiant is square/rectangle in shape with cropped corners.

Diamond Certificates

A diamond certificate (aka – diamond plot, diamond grading report) is a document certifying a diamond is genuine and is created by a group of gemologists after the diamond is carefully evaluated.  The report contains information such as carat weight, color, clarity, proportions, and a cut grade for round diamonds.   The certificate also contains a “blueprint” of the diamond’s clarity characteristics.

To understand all aspects of the diamond grading report, click on the GIA link below:


To understand all aspects of the diamond anatomy, click on the GIA link below: