There are four factors that determine the value of a diamond, collectively known as the 4Cs of Diamonds. The best way to shop for a diamond is to have a good understanding of the 4Cs and determine which factors are most important to you, as each “C” means something different for each individual. For example, some women care most about the carat weight and diamond size, while others might consider the clarity and cut more important. A diamond jewelry purchase should never be based on the specifications alone.
 
A jeweler is your best source of information, but review each page dedicated to the 4Cs of diamonds to learn what you should look for when searching for your next diamond jewelry purchase -- whether online or at jewelry stores near you. Here's a handy guide to the Diamond 4Cs charts (pdf) to bring with you as you shop.

Diamond Carat Weight

Carat weight measures a diamond’s weight and size. Because large diamonds are rare, they generally have a greater value per carat.
Learn about diamond carat weight >

Diamond Clarity

A diamond’s clarity is affected by any external and internal characteristics created by nature when the diamond was formed or as a result of the cutting process. Learn more about diamond clarity and see diamond clarity charts in this section.
Learn about diamond clarity >

Diamond Color

While the most popular diamonds are colorless, diamonds come in every color of the spectrum. Diamond color grades are determined by professionals under ideal circumstances, a situation seldom duplicated outside of a laboratory. Choose a diamond based on its appeal to you, rather than on a technical color scale.
Learn about diamond color >

Diamond Cut

Each diamond is cut to very exacting standards. The cut is one of the most important quality factors of a diamond, as it affects the diamond’s optical and physical properties, like brilliance – how a diamond reflects light.
Learn about diamond cut >
Diamonds and gemstones are cut into many different shapes, each with their own aesthetic and cutting requirements. While diamond and gem shapes are sometimes referred to as the cut (for example an emerald-cut diamond), the cut refers to how a jeweler cuts the gemstone to achieve its symmetry and proportion.

Most people are familiar with the round solitaire diamond and common "fancy" shapes -- which refer to a gemstone cut in any shape other than round. Fancy cuts include such shapes as baguette, emerald, triangle, pear, princess, oval and marquis. If you are uncertain about a term used to describe your diamond, ask your professional jeweler to clarify it for you.

Use our chart of diamond and gemstone shapes to identify your favorite:

diamond-shape
Technological advances in recent years have made it possible for natural diamonds to be enhanced, which increases their beauty and affordability, or grown in a laboratory environment. It’s important to discuss with your professional jeweler if the diamond you are purchasing has been enhanced in any way. Some treatments require special care, of which you need to be aware. 
To many, cut is considered the most important of aspect of a gemstone’s quality and value. Diamond cut affects some of its optical and physical properties including how it reflects light and “sparkles.”

The Diamond Cut Process

Diamond cut refers to how the jeweler physically cuts the diamond stone into its shape and to the proportions and symmetry that achieve optimal light dispersion, which affects a diamond’s quality and price.

Each diamond is cut to very exacting standards. Let’s look at the process to cut a beautiful diamond to better understand the terminology the jewelry industry uses to explain diamond cut factors.

The most common cut, the round brilliant, has 58 facets, or small, flat, polished planes designed to yield the maximum amount of light reflected back to the viewer.

A diamond’s light reflection, known as brilliance, is an extremely important factor in evaluating the quality of a diamond’s cut. A poorly cut diamond will actually lose light and appear dull.

The widest circumference of a diamond is known as the girdle. Above the girdle of a brilliant cut diamond are 32 facets plus the table, which is the largest and topmost facet. Below the girdle are 24 facets plus the culet, or point. 

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Proportion diagrams will typically include the following information:

Depth: The height of a gemstone measured from the culet to the table.
Table: Located at the top of the diamond, the table is the largest facet of a diamond.
Girdle: Range of girdle thickness.
Culet: Appearance, or lack thereof, of the culet facet.

A diamond’s cut impacts four aspects of the stone’s optical and physical properties:

Luster: The quality and amount of light that is reflected off just the surface of the diamond. Luster is directly related to the hardness of the stone and the quality of its polish.

Brilliance: The amount of white light that is returned to the eye from both internal and external surfaces. Brilliance is determined by the quality of the diamond’s polish and the number and size of inclusions inside the gem.

Dispersion: The display of spectral or rainbow colors seen coming from the inside of a diamond. Often referred to as “fire,” dispersion is directly related to how well the stone is proportioned.

Scintillation: A diamond will show scintillation, or “sparkle,” when movement is involved. The viewer, the light source or the diamond itself must be in motion for scintillation to occur.

The most important part of choosing a diamond is to choose one that appeals to you personally. While it is beneficial to understand the technical aspects of diamonds, it is most essential to fall in love with your diamond. Visit your local Jewelers of America member jewelry store to work with a professional jeweler who can show you a range of diamonds and explain their unique characteristics.

Diamonds come in every color of the spectrum, but the most popular are colorless. Truly colorless, pure white diamonds are extremely rare and, therefore, the most costly. Laboratories, like the Gemological Institute of America (GIA), grade stones according to how far they deviate from the purest white as one of the diamond 4Cs.

The best way to see the true color of a diamond is by looking at it against a white surface. Colorless stones are graded D, E or F. All three grades are considered colorless but with slightly decreasing transparency. Color grading continues down through the alphabet, with each letter designating a slight darker or warmer tint.

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Colored Diamonds

Diamonds also come in a spectrum of majestic colors, from red and canary yellow to blue, green and purple. These colorful diamonds, known as fancies, are valued for their depth of color, just as white diamonds are valued for their lack of color. Therefore, fancy color diamonds are graded in order of increasing intensity from Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Dark and Fancy Deep.

Diamond color grades are determined by professionals under ideal circumstances, a situation seldom duplicated outside of a laboratory. Choose a diamond based on its appeal to you, rather than on a technical color scale.

A Note on Color Grading

It is important to remember that color is a range. Think of a diamond color grade as your age. If you’re 34 years old, your 34th birthday may have been yesterday, or your 35th birthday may be next month. But when someone asks your age, you simply tell them you’re 34. It works the same way with color grading. For example, a diamond with a G color grade could, in fact, be very close to an F or to an H.

Carat weight is one of the 4Cs of diamonds that measures measures a diamond’s weight and size. The term "carat" is derived from the carob seeds that were used to balance scales in ancient times.

Today’s metric carat is equal to 200 milligrams, or one-fifth of a gram, and there are approximately 142 carats to an ounce. Carats are further divided into points. There are 100 points in a carat. A half-carat diamond may be referred to as a 50-point stone.

Because large diamonds are rare, they generally have a greater value per carat. When considering the value of a diamond or gemstone, two diamonds or gems of equal carat weight can have differing price points based on the quality of cut, color and clarity -- the three other diamond quality factors. A professional jeweler, like a member of Jewelers of America, is educated to distinguish and explain the various diamond quality factors so you find the highest quality diamond that fits your budget.


Diamond Size Chart


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Image not to scale when viewed on mobile devices.
A diamond’s clarity, one of diamonds 4Cs, is affected by any external and internal characteristics created by nature when the diamond was formed or as a result of the cutting process.

Characteristics such as internal spots or lines are called inclusions. Although these marks make each stone unique, the fewer the inclusions, the more valuable the stone. Inclusions can sometimes interfere with the passage of light through the stone, diminishing the sparkle and value of the diamond.

According to the quality analysis system of the Gemological Institute of America (GIA), clarity is graded on a scale ranging from Flawless (Fl) to Imperfect (I). Only a tiny percentage of diamonds ever achieve a grade of Flawless.


Diamond Clarity Scale


diamond-clarity-scale

A Note on Diamond Clarity

It is important to remember that clarity is a range. Think of a clarity grade as your age. If you’re 34 years old, your 34th birthday may have been yesterday, or your 35th birthday may be next month. But when someone asks your age, you simply tell them you’re 34. It works the same way with clarity grading.

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Rare and fascinating, mysterious and magical, the diamond has ignited romantic passion throughout history. The word alone conjures up a thousand images of rare, precious, desirable, beautiful, sparkling tokens of love. This guide from Jewelers of America details what you should know when buying diamonds or diamond jewelry for yourself or someone you love.

One of the most important aspects of buying quality diamond jewelry is where you shop. A trustworthy jeweler or jewelry store, like members of Jewelers of America, will walk you through the jewelry shopping experience and take you on an educational journey about diamond information.

The information in our diamond jewelry guide is intended to help you browse for diamond jewelry in advance of your purchase and understand the basic diamond quality factors so you can feel comfortable starting a dialogue with any jewelry salesperson.

A Diamond’s Unique Characteristics

Diamonds might not be the rarest gemstone known to man, but they have a set of unique characteristics that sets diamond jewelry apart from other gemstones and gives them a value beyond price. When considering a diamond jewelry purchase, a jeweler might first inform you of these special features of a diamond:

Unique Beauty 

The beauty and inner fire of the diamond has made this precious gem prized for centuries. Each stone, like its owner, is endowed with a personality and character uniquely its own. 

Durability

A diamond is the hardest substance known to man (ranking 10.0 on the Mohs Hardness Scale) and is resistant to deterioration. When cared for properly, diamond jewelry can be worn every day and passed on as an heirloom to future generations.

 

Enduring Value

Gem-quality diamonds have consistently retained their value, and most often have increased in value, after years of being worn and enjoyed.

4Cs of Diamonds

There are four factors that determine the value of a diamond, collectively known as the 4Cs of Diamonds: Carat, Clarity, Cut & Color. The Diamond 4Cs are so important to selecting the perfect stone for you that we cover them indepth. Go to our guide on the diamond 4Cs >

Where to Buy Diamond Jewelry

Since expertise in the grading, selection and sale of diamonds takes years of training, always purchase diamond jewelry from a professional you can trust. Choose a retailer who has demonstrated a commitment to professionalism and has an established reputation. Ask if the jeweler is a member of Jewelers of America. Our members commit annually to a Code of Professional Practices, so you can buy jewelry with confidence.  Search our “Find a JA Jeweler” directory, or look for the “J” logo on company’s door or website.

The jewelry store experience should be relaxed and fun. The best jewelers are passionate about their craft and love sharing their knowledge with customers. They will show you a selection of diamonds and be able to explain the subtle differences in grade and value. The knowledge and expertise you gain in the jewelry store will guide you in choosing the perfect diamond for a lifetime of wearing pleasure.

A big plus of establishing a relationship with a jewelry store near you is that they will be there for your future purchases, repairs or custom design needs.

Caring for Your Diamond

Diamonds may be the hardest substance known to man, but they still can be damaged, abraded or scratched. Use the following guidelines to ensure your diamond jewelry retains its beauty for years to come:

  • Don’t jumble your diamond jewelry with other pieces, because diamonds can scratch other jewelry and each other.
  • Keep your diamond jewelry in a fabric-lined jewel case or in a box with compartments or dividers.
  • Don’t wear your diamonds when doing rough work. Even though a diamond is durable, a hard blow can chip and damage it.
  • Diamonds look best when they are clean, revealing the diamond’s fire and brilliance. Clean your diamonds regularly using commercial jewelry cleaner, a mix of ammonia and water, or a mild detergent. Dip the jewelry into the solution, and use a soft brush to dislodge dust or dirt from under the setting.
  • Keep diamond jewelry away from chlorine bleach or other chemicals that can pit or discolor the mounting. Do not wear your diamond jewelry in chlorinated pools or hot tubs.
  • See your professional jeweler at least once a year to have your diamond jewelry professionally cleaned and checked for loose prongs and wear.

Visit our Jewelry Care section for more information on how to clean and care for your fine jewelry.


Find a JA Jeweler

There are over 8,000 JA Member jewelers across America. Find a store near you:

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