Diamonds
Members of the Cornwell Family have been helping people select diamonds for over 150 years. No two diamonds are alike, and although you can learn a lot about diamonds, without training it is extremely difficult to tell the difference between them. Know your jeweler. At Cornwell Jewelers, we have the training and skill to assist you. The 4Cs are the basics of diamond beauty and value. The 4Cs are cut, color, clarity, and carat weight. These are in order of their importance of how they affect the beauty and value of a diamond. The American Gem society has a grading system for all of the 4Cs. The scale ranges from 0 to 1, with 0 being the highest quality. There is also a 5th C — confidence. Wherever you choose to buy your diamond, you need to have confidence in that person to be your expert.
Cut
Cut is the most important factor of a diamond’s beauty and value. In its natural state, a diamond’s beauty is generally concealed. What draws out its brilliance is the cut, which under ideal circumstances maximizes the optical properties within, particularly the diamond’s ability to refract light and disperse color. Not to be confused with the shape of a diamond, cut refers to the arrangement of a diamond’s facets. The American Gem Society grading scale for round brilliant diamonds is based from 0 to 10. When a diamond captures and releases the maximum play of light it receives a 0 grade - called an ideal cut.
To achieve an ideal cut, the diamond cutter must adhere to a whole series of exacting tolerances. Those tolerances, in turn, may well mean that much of the rough diamond has to be cut away. For this reason, ideal cut diamonds are the exception rather than the rule. Fewer than 1% of all diamonds are cut to ideal proportions. Consequently, you’re likely to find ideal cut diamonds in only the finest stores. A store dedicated to cut will have a saran machine or proportion scope to verify cut. Before a diamond cutter is allowed to cut a one carat diamond, he or she must apprentice for 10 years.
Cut is the most critical of all the variables that affect the value of a diamond. Cut can affect the value up to 60% of the diamond’s worth. It is essential that you know the quality of the cut when purchasing your diamond.
Color
Color is the second of the 4Cs. Although most diamonds appear white, they do in fact range from colorless to yellowish, with many graduations in between. Colorless diamonds are the most valuable. Because subtle color variations dramatically affect a diamond’s value, the 0 to 10 grading scale is used. Diamonds graded from 0 to 3 are in the high-quality range. At 3.5, the diamond will begin to have a faint yellow appearance.
At Cornwell Jewelers we grade a diamond’s color using an AGS colored graded master diamond set and a diamond light. Many jewelers lack the expertise and equipment to accurately classify a diamond’s color. For a person not gemologically trained and without the proper grading equipment, you would notice a difference between two unmounted diamonds that were four color grades apart in the 0 to 3 range.
Clarity
Clarity is the third of the 4Cs. Clarity refers to a diamond’s internal and surface characteristics. Diamonds form between 75 and 120 miles below the Earth’s surface -- the only place the necessary temperature and pressure conditions exist. During the formation process, changes in pressure or temperature can create minute fractures in the diamond. Other materials that enter during the formation of the diamond can also create internal characteristics.
The AGS grading scale from 0 to 10 is used. Diamonds graded from 0 to 6 are considered high in quality. The grade is based on the number, size, and location of the characteristics. These occur naturally in diamonds and are referred to as “nature’s beauty marks.” The fewer and smaller the characteristics, the less they interfere with light as it passes through the diamond.
Clarity is graded using a 10x microscope. In diamonds graded from 0 to 6, there will be no visible characteristics through the top of the diamond. The differences among diamonds in this clarity range can only be seen through a microscope. A flawless diamond (grade 0) is extremely rare and extremely valuable. Diamonds with significant characteristics have a much lower value and their durability could be affected.
Carat
Carat weight may be the least important of the 4Cs in determining the value of a diamond. Despite the ease of measuring weight and the relative insignificance of weight in determining the value of a diamond, there are some facts you should understand about weight and value. As diamonds increase in size, their cost increases geometrically rather than arithmetically. This means that a one carat diamond can cost significantly more than a one-half carat diamond of equal quality. On the other hand, when a diamond is improperly cut, the additional weight may reduce its brilliance.
Diamond weight is based on points; for instance, a diamond that is 52 points is a little over a half of a carat. A full carat is 100 points. The largest gem diamond ever recorded is the Cullinan, which weighed 3,106.70 carats. The diamond was mined in South Africa in 1905. Once cut, the largest of the gems was a 530.20 carat pear shape.
Confidence
Many people have heard of the 4Cs before coming to the Internet for more information. The fifth C, often not discussed, is the most important – confidence. You can learn about aspects of diamond value and grading, but without formal training it would be extremely difficult to distinguish the difference between two diamonds of similar quality.
Know your jeweler. If you are not a jewelry expert, find someone who is. You should have confidence in wherever and whomever you select your diamond from. A member of the American Gem Society is a great place to start. AGS member stores, like Cornwell Jewelers, have trained professionals who know jewelry. We are your diamond experts.
Shape
Shape, which isn’t to be confused with cut, merely means the geometric form of the diamond. Based on the crystalline structure of the rough diamond, cutters decide what shape to cut the diamond. Popular shapes include those shown here.
Certificates
“Certs,” as they are called in the diamond world, are reports completed by a lab about their opinion of a diamond’s quality factors. There are many labs that offer reports, however the labs we use are the American Gem Society and the Gemological Institute of America. The AGS lab offers a cut grade for round, brilliant diamonds. Diamonds graded by these labs must be completed when the diamond is unmounted, so all of its characteristics can be viewed. Diamonds graded in a mounting cannot be done as accurately.
Even though a diamond has been graded by a lab, you still need an expert to verify it. Unfortunately, there have been forged lab reports. Also, humans can error. That’s why we check and double check our diamonds for accuracy of grading. A second opinion of your diamond’s quality factors is a good idea, especially if it is over ½ carat.
Are diamonds forever?
Diamonds are the oldest substance known to man and are the hardest gemstone. Even though diamonds are extremely durable, due to their crystalline structure, they can be nicked or chipped, especially on the outside edge of the diamond.
All fine jewelry should be worn with care. Just like you wouldn’t wear your favorite dress shoes to mow the lawn, you shouldn’t wear fine jewelry during times when it could be damaged. Worn with a little care, a diamond will last forever. What else can be handed down from generation to generation, and look the same as the day you got it? Diamonds are forever.
