Diamond - How to Buy?

How to Select a Diamond

What makes one diamond worth more than another? How do you get quality and value? Katarina's diamond education pages will help answer all your questions. Learn about the four C's (cut, color, clarity, and carat weight), how those characteristics affect appearance and price, and which characteristics are most important.

Understanding the essential characteristics of diamonds will allow you to shop for diamond jewelry with confidence. We want to take the mystery out of diamond shopping—while acknowledging the air of mystery that will always surround this most fascinating and highly prized precious stone. And if you need more information, simply email us at sales@katarina.com or call our customer care department at 888-528-2746 and we will happily answer your questions!
 
Shape
Shape means the form of the diamond as viewed from above. (Shape is different from cut, which is discussed below.) Choosing a shape is largely a matter of personal style and preference, although shape can affect the appearance of a diamond, emphasizing its clarity or making it appear larger, for example.
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Cut
Cut refers to the number and placement of the angles, or facets, applied to a diamond. Cut is one of the most important characteristics to understand, because it has the most influence on a diamond's "sparkle."
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Color
When it comes to the color of diamonds, less is more.The most valuable and rare diamonds are colorless. (They may also be referred to as "white.") The more visible color in a diamond, the lower color grade it receives. Color is rated differently in "fancy color diamonds"—blue, pink, or yellow diamonds whose color is intentional and part of the diamonds' appeal.
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Clarity
Most diamonds carry small natural imperfections—the fewer the imperfections, the higher clarity grade a diamond receives. It's important to understand how these minute flaws affect a diamond's appearance. Most are not visible to the unaided eye, so they have little effect on a diamond's beauty.
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Carat Weight
The carat is a measure of weight. The number of carats tells you the overall size of a diamond, but keep in mind that the shape and cut of a diamond can affect how large the stone appears to the viewer.
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Certification
Certified diamonds come with a report from an independent diamond grading laboratory, stating the stone's color, clarity, carat weight and other characteristics.
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FAQ
Answers to frequently asked questions about diamonds.
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Shape
    Top Tips
  • Choosing a shape is largely a matter of personal style and preference.
  • Shape can emphasize certain characteristics of a diamond, for example, brilliance, clarity, or carat weight
Diamond Shape - Katarina
   
Round  
The most popular diamond shape today, the round diamond symbolizes the eternal circle of love and commitment. The round brilliant cut diamond is also the most researched. Diamond cutters have almost a century of experience and mathematical formulas to draw on when cutting a round diamond for optimal fire and brilliance. Because of this knowledge, a round cut is a good choice when trying to balance cut, color, and clarity grades to get the brilliance you want at the price you prefer.
   
Asscher  
This shape is named after the Dutch diamond cutter Joseph Asscher, who designed it in 1902. The shape gained in popularity after the British Royal Family invited Asscher to cut the Cullinan diamond, a rough diamond over 3,000 carats in size. Like the emerald shape, this square diamond has rectangular facets in its pavilion that create a unique optical effect. And like the emerald, the Asscher shape features a larger, open table (the flat facet on top of the diamond) that highlights the clarity of a diamond. In diamonds of clarity grades SI or lower, larger inclusions may be more visible in the Asscher shape. For the classic square Asscher look, choose a length-to-width ratio between 1.00 and 1.05. To avoid visible color in the diamond's corners, choose color grades K or higher.
   
Emerald  

The emerald cut is rectangular, with rectangular facets in its pavilion (the bottom portion of the diamond) that create a unique optical effect and give the cut its special beauty. The emerald is often referred to as "step cut" because its broad, flat concentric facets resemble stair steps. With its larger, open table (the flat facet on top of the diamond), this shape highlights the clarity of a diamond. In diamonds of clarity grades SI or lower, larger inclusions may be more visible in the emerald shape. Emerald-cut diamonds can vary greatly in how rectangular they are. The length-to-width ratio will determine what the diamond will look like when viewed from above. For the most pleasing proportions, look for a length-to-width ratio between 1.30 and 1.40.

   
Oval  
The oval cut produces beautiful fire similar to that of a round diamond. A longer oval shape can highlight long, slender fingers. The exact shape of the oval can vary significantly. The length-to-width ratio will determine what the diamond will look like when viewed from above. For classic oval proportions, choose a length-to-width ratio between 1.33 and 1.66
   
Marquise  
When it is important to maximize carat weight and make a diamond appear larger, Katarina recommends the marquise cut. Like the oval cut, the marquise gives an elongated look to the wearer's fingers. This diamond is often set with side stones to beautiful effect. For the most graceful marquise proportions, look for length-to-width ratios between 1.75 and 2.25.
   
Pear  
With its single point and rounded end, this diamond shape is also known as a teardrop. A longer pear shape can make the fingers appear long and slender. Choose a length-to-width ratio between 1.45 and 1.75 for the most pleasing proportions.
   
Radiant  

The radiant diamond is square or slightly rectangular with trimmed corners and looks wonderful with side stones. If you prefer a square shape, Katarina suggests length-to-width ratios between 1 and 1.05. If you want a more rectangular diamond, look for length-to-width ratios greater than 1.10.

   
Princess  
Another favorite for engagement rings, the princess is square or rectangular in shape and offers lovely brilliance. Other than round, princess is the only shape whose cuts can be graded as ideal (the highest cut grade). To find the dimension of princess you want, look for the length-to-width ratio, which determines what the diamond will look like when viewed from above. For the most aesthetically pleasing dimensions in a square princess cut, Katarina recommends length-to-width ratios between 1 and 1.05. If you prefer more of a rectangular shape, look for length-to-width ratios greater than 1.10. To avoid visible color in the diamond's corners, choose color grades K or higher.
   
Heart  
This universal symbol of love is popular for engagement rings. For a nicely proportioned heart shape, look for length-to-width ratios between .90 and 1.10. To avoid visible color at the diamond's edges, choose color grades K or higher.
   
Cushion  

At Katarina, we love the vintage feel of the cushion cut's rounded corners and larger facets, which also serve to increase the diamond's brilliance. The larger facets emphasize the diamond's clarity, so be sure that any inclusions in an SI or lower clarity stone do not affect its appearance. Cushion-cut diamonds, also called pillow-cut, are square or rectangular. For a square shape, look for length-to-width ratios between 1 and 1.05. In a rectangular diamond, choose length-to-width ratios greater than 1.15.

 
Cut
    Top Tips
  • Cut is the most important attribute to consider when selecting a diamond.
  • It has the greatest overall influence on a diamond's beauty because it creates much of a stone's sparkle.
Diamond Cut - Katarina
   
Cut is the one characteristic of a diamond that nature does not influence; the quality of the cut results from the skill of the cutter. The facets given to the diamond's surface will help it shine brilliantly—or, if the cut is poor, weaken its spark.
Given that cut has the most influence on a diamond's sparkle, Katarina recommends choosing the highest cut grade that is within your budget.
Cut grades range from ideal to poor and tell how much light is reflected from the diamond. The best cuts reflect light out of the top (called the "table") of the diamond. An ideal cut reflects nearly all light that enters the diamond. Cuts that are too shallow or too deep are equally poor; in a too-shallow cut, light escapes from the bottom of the diamond, while a cut that is too deep allows light to leave through the side of the stone.
For fine jewelry such as engagement rings, Katarina recommends cuts rated very good or good to provide brilliance at an excellent value.
   
Fully Faceted vs. Single Cut Diamonds  

Katarina uses fully faceted diamonds whenever possible in our jewelry—including our fashion pieces. Many of our competitors use single cut diamonds in their fashion jewelry. Single cut diamonds have only 18 facets. That may sound like a lot, but compare it to 58—the number of angles on a fully faceted stone! We use fully faceted diamonds wherever possible to create the most sparkle and fire, even in a lower-cost piece of fashion jewelry. Our customers tell us they can see the difference!

   
Cut Grades    
     
Ideal cut:    

Reflects nearly all light that enters the diamond, and is exceptional quality. The top 3% of diamond quality based on cut.

     
Very good cut:    

Reflects only slightly less light than the ideal cut, and carries a lower price. The top 15% of diamond quality based on cut.

     
Good cut:    
Reflects most light that enters the diamond, and is much more affordable than a very good cut. The top 25% of diamond quality based on cut.
     
Fair cut:    
Still considered quality, but the diamond's fire will not be as brilliant as in a cut that is rated good or higher. The top 35% of diamond quality based on cut.
     
Poor cut:    
So deep or shallow that the cuts lose most of the light out the sides and bottom of the diamond. Katarina does not carry diamonds whose cuts are rated poor.
     
Color
    Top Tips
  • The more colorless (or white) a diamond is, the better color grade it receives. (Except in the case of "fancy color" diamonds, in which color is desirable.)
  • A color grade of D is the highest possible, while Z is the lowest.
  • As a characteristic, color is only slightly less important than cut.
Diamond Color
   

Color is an important characteristic to consider when selecting a diamond, second only to cut. Color is rated using the letters D through Z, with utterly colorless diamonds scored as D. The yellower a diamond is, the lower color rating it receives.
Katarina recommends diamonds with color ratings ranging from G to J for the best combination of beauty and value; their color is not detectable to the unaided eye, but they are less expensive than D through F diamonds.

   
Clarity
    Top Tips
  • Clarity is a measure of the number and size of the tiny flaws that are present in virtually all diamonds.
  • Many of these flaws are microscopic, and do not affect a diamond's appearance.
  • Clarity has the least impact on a diamond's sparkle, so it is a less important characteristic than cut or color.
Diamond Clarity
   

Most diamonds carry small natural imperfections called inclusions. The fewer the inclusions, the higher clarity grade a diamond receives. The highest clarity diamonds are rated FL ("flawless"), or VVS ("very, very slightly" included) and are the most expensive. At the other end of the spectrum, low-quality diamonds with inclusions that are visible to the unaided eye are rated I ("included"). Clarity grades are further divided into 1 and 2, with 1 indicating better clarity. So a diamond rated VS1 has slightly better clarity than one rated VS2.
The idea of flaws in your diamond might be alarming, but in many cases clarity is actually the characteristic that has the least effect on a diamond's appearance. Most inclusions are microscopic.
The best value can be found in diamonds rated VS ("very slightly" included) and SI ("slightly included"). The imperfections in most VS or SI diamonds cannot be seen without magnification, and do not detract from the stone's beauty.
Fashion jewelry uses diamonds with lower clarity ratings, typically SI or I. Fashion jewelry is intended to change according to current fashions—it's not an investment or an heirloom, the way fine jewelry pieces such as engagement rings are. Fashion jewelry is meant to be affordable, and the diamonds in fashion jewelry are generally smaller than the diamonds in fine jewelry, at which size inclusions are impossible to detect.

 
Diamond Clarity Ratings    
     
FL, IF
Flawless/Internally Flawless:
   

No inclusions. The rarest and most costly diamonds.

     
VVS1, VVS2
Very, Very Slightly Included:
   

Very difficult to see flaws under 10x magnification. A superb quality diamond.

     
VS1, VS2
Very Slightly Included:
   

Flaws are not typically visible to the unaided eye. More affordable than the VVS1 or VVS2 grades.

     
SI1, SI2
Slightly Included:
   

Flaws are visible under 10x magnification, and may be visible with the unaided eye. A good value.

     
I1, I2, I3
Included:
   

Flaws visible to unaided eye. These are among the least expensive diamonds, but the inclusions may result in some loss of brilliance.

     
Carat Weight
    Top Tips
  • Carat represents a diamond's weight, but the diamond's perceived size will also be affected by shape and cut.
  • The size of the diamond as it appears when viewed from the top (for rings) or from the front (for necklaces) is important because that is how it will normally be seen.
  • To gain an accurate picture of diamond size, carat weight should be considered along with the distance across the top of the diamond and the diamond's cut grade.
Diamond Carat Weight - Katarina
The carat is a measure of weight. The number of carats tells you the overall size of a diamond, but other factors can affect how large the stone appears to the viewer. To gain an accurate picture of diamond size, you should considering carat weight with two other traits: 1) the distance across the top of the diamond measured in millimeters, and 2) the diamond's cut grade.
The distance across the top of the diamond is significant because this is how we see most diamonds in their settings.
A diamond's cut grade is important because, as discussed in the cut section, a diamond that is cut with the proper proportions reflects the maximum amount of light out of the top of the diamond. A well-cut diamond appears larger because of its sparkle. Conversely, a poorly cut diamond may have more of its carat weight concentrated in the base of the diamond, making the diamond appear smaller than you would expect based on its carat weight. So a diamond that is technically smaller according to its carat weight can appear larger than a diamond that weighs more but is poorly cut.
You may see diamond weight measured in points instead of carats. Carats are made up of points, with one carat equaling 100 points. For example, a 1/2 carat diamond weighs 50 points.
Katarina recommends that you first select your cut, color, and clarity grade, and then determine the carat weight of diamond that will fit within your budget.
To see examples of how diamonds of different carat weights look when set in a ring, check out this chart. You will see that when viewed from the top, a 2 carat diamond does not appear to be twice the size of a 1 carat diamond—another example of how carat weight alone cannot tell you how large a diamond will look.
   
Choosing Your Carat Weight  
Consider the size of her finger (for a ring), the size of your setting, and your budget.
When buying a ring, know that the smaller the finger, the larger a diamond will appear. A 1 carat diamond looks much larger on a size 4 finger than on a size 8.
Not all settings will work with all diamond carats or shapes. If you already have a setting, check its specifications or call Katarina (888-528-2746) for help.
If you prefer a larger carat weight, yet you're working within a strict budget, consider a diamond with a good cut, SI1-SI2 clarity, and an I or J color grade, if you want a diamond solitaire. Another way to create a bigger "look" at a lower overall cost is to add side stones to a center diamond.
Another strategy for value is to choose a diamond that is just below a full- or half-carat weight. For example, a diamond that is 0.90 carat costs less than a diamond that is 1 carat, but the size difference is almost impossible to detect because carat weight is distributed across the whole diamond.
   
Certification

Certified diamonds are evaluated by an independent diamond grading laboratory, which issues a certificate stating the stone's color, clarity, carat weight and other characteristics. The certificate ensures that you are getting the diamond with exactly the characteristics you want. Certification applies to loose diamonds and larger diamonds, such as those in engagement rings. The smaller diamonds typically used in fashion jewelry are not certified.
There are several different independent diamond grading laboratories. The American Gem Society Laboratory (AGSL) and Gemological Institute of America (GIA) are considered to be the most conservative and consistent. Other labs include the International Gemological Institute (IGI) and the European Gemological Laboratory (EGL).
There is expense involved in certification. AGL and GIA charge a premium for their certification processes—a cost that Katarina must pass on to customers. It costs less to certify diamonds through IGI and EGL. Katarina certifies some of its diamonds through IGI and EGL, which allows us to offer the best value to our customers on the most popular diamonds.
Our diamonds that are uncertified receive our own evaluation of cut, color and clarity. It is in our interest to provide fair and accurate evaluations. We want our customers to be completely happy with the quality and beauty of their diamonds. As always, all purchases from Katarina can be returned within 30 days of purchase for a full refund.

 
FAQ
  Cut  
  What are polish and symmetry? How do they affect a diamond's brilliance?  
  Polish is the smoothness of a diamond's facets. The term symmetry refers to the arrangement of the facets. These characteristics are graded during certification. While polish and symmetry do have some effect on a diamond's sparkle, cut is far more important. Comparing the polish and symmetry of two diamonds that are otherwise identical is a good way to choose between them.  
  How do you measure the quality of cut?  
  Grading laboratories use an optical measuring device to create a three-dimensional model of the diamond's proportions and angles. Then computer modeling can trace light behavior and measure its levels of brilliance, fire and sparkle as it exits the top of the diamond, and discover where light is being lost if the cut is poor.  
  Why can't I find a diamond with an ideal cut grade in the shape I want?  
  Independent grading laboratories have only established standards for an ideal cut in round and princess shapes at this time.  
  What is the difference between fully faceted diamonds and single cut diamonds?  
  A fully faceted diamond has a minimum of 58 facets applied to it. A single cut diamond has only 18 facets, which results in less sparkle and brilliance. At Katarina, we use fully faceted diamonds whenever possible in our jewelry. Lesser-quality fashion jewelry is often made with single cut diamonds. Our use of fully faceted diamonds wherever possible is just one example of how Katarina provides you with superior quality at a great price.  
  In a three-stone ring, should you choose side stones with the same cut, color and clarity as the center diamond?  
  At Katarina, we find that keeping the cut grade the same for each of the diamonds produces the most pleasing appearance. However, color and clarity can differ. Color can vary up to three grades without a visible difference. For example, D, E, and F will match. Similarly, any stone with a clarity of VS2 or above will look the same.  
     
  Color  
  What is fluorescence? How does it affect the color of a diamond?  
  Fluorescence is a bluish glow that some diamonds produce under ultraviolet light. Fluorescence has no effect on diamond color as seen in normal light. Still, this quality is rated by diamond grading laboratories, as none, faint, medium, strong, or very strong. Diamonds with a strong or very strong fluorescence are a good value for consumers because the market prices them slightly lower than diamonds with less fluorescence.  
  What are "fancy color diamonds"?  
  Natural fancy color diamonds are extremely rare and valuable. They are created when diamonds are exposed to certain trace elements while the diamonds are forming deep within the earth. Naturally occurring colored diamonds can be almost any hue of the rainbow—as can artificially colored diamonds. Color can be applied to diamonds through a variety of processes, such as dyeing or irradiation. Artificially colored stones are a fraction of the price of naturally occurring colored diamonds, and offer a way to obtain the interest and style of colored diamonds when working within a budget. Blue diamonds have become very popular in recent years.  
     
  Clarity  
  How important is clarity in determining a diamond's brilliance?  
  Clarity refers to the number and size of the inclusions (imperfections) that occur in almost all diamonds. In most cases, these imperfections are microscopic, so they do not affect a diamond's beauty. Cut has a much larger effect on brilliance than clarity does, and an expert cut can help camouflage the imperfections of a diamond with a lower clarity grade. In diamonds rated SI or higher, the inclusions have no discernable effect on a diamond's sparkle. Diamonds with clarity ratings I1, I2, or I3 can have inclusions that are visible to the unaided eye—in extreme cases, those flaws might slightly diminish a stone's brilliance.