No matter what type of diamond jewelry you are shopping for - diamond engagement rings, diamond earrings, diamond necklaces or diamond bracelets, there are some things you need to know to help you select the best diamonds for your money. These guidelines are called the 4 C’s. The 4 C’s are carat, clarity, cut and color.
The simplest factor used to determine the value of a diamond is carat weight. The words carat and karat are often confused. Karat is the word we use to refers to the percentage of pure gold in a gold charm, pendant, chain, earrings or other pieces of gold jewelry. Pure gold is 24 karat. When we say 14 karat, we are talking about jewelry that is 14/24 pure gold. That is why you may see a 14 karat gold piece stamped 585 which indicates it is 58.5% pure gold. 10 karat may be stamped 417.
When the word carat is used it refers to the actual weight of gemstones. The word carat comes from the Greek word for carob bean. In ancient times carob beans were used to measure the weight of things. Each carob bean weighs exactly 1/5th of a gram. Therefore, one carat equals exactly 1/5th of a gram. One carat is divided into 100 points, so a diamond weighing ¾ carat has 75 points or .75 carats. Although the carat weight has nothing to do with the beauty of the diamond, it certainly has a lot to do with the rarity of the stone, which dramatically impacts the value of the gemstone.
As diamonds increase in size and weight, their price per carat increases geometrically, not mathematically if the other 3 C's are equal. Thus, a two-carat diamond will be more than double the price of a one-carat diamond of the same quality. Diamonds are weighed loose on a calibrated scale to provide a highly precise diamond weight and are specified on the Diamond Report to two decimal points. The carat weight of a diamond or other gemstone has nothing to do with the quality or beauty of the stone. The three C’s that determine the beauty are color, cut and clarity.
Although diamonds come in every color under the sun when we refer to the color grade of a diamond we give it a grade based on how colorless it is. Colorless diamonds are very rare. Almost all diamonds have at least a slight tint of yellow, brown or gray, or a combination of these colors. The Gemological Institute of America set the standard with their grading chart which is a letter scale ranging from the letter D through Z. D,E,F are all considered colorless, G to J are called near colorless. The color in a diamond becomes more and more noticeable as we go from K to Z. If a diamond has more color than Z and the color is attractive we call it a fancy color diamond. But what we are talking about here are diamonds with grades from D to J. To determine a diamonds true color, the diamond is viewed from the side under balanced white light. It is compared to diamonds in a master set whose colors have been predetermined by the Gemological Institute of America.
This analysis is done with the unaided eye under no magnification. While most people will not notice the actual color of a diamond with a little education and experience it will become much more obvious. Therefore, once a diamond’s clarity has been determined to be SI1 or above and the stone is eye clean almost everyone agrees it is much more desirable to look for a diamond with high color instead of paying extra money to increase the clarity of your diamond. Remember, you can see color with your unaided eye. The more you get to actually look at and handle a diamond the better you will become at judging color and the more comfortable you will feel about selecting a diamond you will enjoy forever!
The Castle’s diamonds are color graded in an accredited gem laboratory or by our on site Graduate Gemologist under controlled lighting and precise viewing conditions by comparing them to master stones of established color grade. Each diamond receives a color grade based on the GIA’s color-grading scale which is the industries most widely accepted grading scale.
How a diamond has been cut, polished, and to what proportions are of utmost importance. Before 1919, there were no strict standards of how diamonds were cut. In that year a 19 year old math student using the refractive index of diamond to determine exact measurements and proportions for a diamond to be shaped to maximize the brilliance, fire and scintillation. That student’s name was Marcel Tolkowsky thus the “Tolkowsky Ideal Cut” was born and in just a very few years the whole world was cutting to much stricter standards.
Cut is the craftsmanship that turns a rough diamond into a work of art. Cut is the most critical factor in releasing a diamonds “fire” and “brilliance”. It is the only factor humans can control. Approximately fifty percent of rough diamond material is usually lost during the cutting process.
Each facet, or plane, of the diamond should be placed in exact geometric relation to each other. The culet or “point” should be in the exact center of the bottom of the diamond and the diamond needs to be well polished. This symmetry is crucial for light entering the diamond to be reflected back to the eye as “fire”. Once these geometric proportions are compromised, the beauty and brilliance of the diamond are sacrificed for size and weight.
An ideal cut diamond reflects light from one facet to another and is dispersed through the top of the diamond. A diamond that is cut too deep allows light to escape through the opposite side of the pavilion. Too shallow of a cut lets light pass through the pavilion of the diamond before it can be reflected.
Some believe that cut is the biggest indicator of beauty and should be made priority over the other C’s. The quality of a diamond’s angles, proportions, symmetrical facets, brilliance, fire, scintillation and finishing details directly impact a diamonds ability to sparkle and its overall aesthetic appeal.
Natural diamonds are formed under tremendous heat and pressure deep in the earth. It is normal during this process for a diamond to have a variety of internal character tics called “inclusions” and external characteristics called “blemishes”. Diamonds are clarity graded under 10X magnification using a loupe or gem scope by a skilled grader. The Castle’s diamonds are clarity graded by an accredited gem laboratory or by our on site Graduate Gemologist. All diamonds are graded on the GIA clarity scale which has 6 categories, some of which are divided for a total of 11 specific grades.
In order to grade the clarity of a diamond it is necessary to consider 5 factors: size, number, position, nature and color or relief of the various clarity characteristics. This analysis is done using a 10x loupe or microscope under the experienced eye of an accredited gemologist.
All diamonds have been identified by nature with natural “inclusions” –crystals, feathers, needles, pinpoints, clouds, etc. These traits developed in the diamond during its formation. Diamond clarity is determined by the absence of these inclusions. The fewer the inclusions, the more rare the diamond and the greater the value. Flawless and internally flawless diamonds are exceedingly rare. The term “flawless” is a highly restricted one. While inclusions may not affect the beauty of a diamond, they do affect it’s value and price.
By definition a diamond is eye clean if it has a clarity grade of SI1 or higher. Lower grades than SI1 may affect the beauty of the diamond. The lower the grade the more effect it will have. No matter how good a diamond may look if it has a durability problem it will be graded no better than I2. The following information was taken directly from the Gemological Institute of America’s Lab Manual.