Before you begin a Diamond Appraisal in Houston:
Diamonds are known not only for beauty and rarity but also hardness. A quick jewelry appraisal reveals that diamonds are the hardest stone known to man, according to the Mohs scale. The only thing that can scratch another diamond is another diamond itself. Besides gemstone use, the majority of diamonds mined are actually for industrial use, especially used for drilling equipment.
Diamonds are durable because of their geological structure and formation. Formed out of carbon in the earth’s mantle, heat and pressure crush the carbon and form crystals, or diamonds. But the diamonds don’t stay in the mantle, several miles below the surface. They migrate closer to the earth’s surface making them easy to mine for through the earth’s natural processes. Gas forces molten rock to move toward the surface of the earth, catching diamonds along the way, before the molten erupts. During the cooling process, and over the years, the molten rock erodes, exposing the diamonds inside.
The 4 C’s:
GIA (Gemological Institute of America) was the institute which introduced the 4 C’s which are recognized by many jewelers in Houston. One part of what the cut of the diamond refers to is the shape it is cut into (Heart, Round, Princess, Cushion, Radiant, Emerald, Ascher, etc.)
Another part of what “cut” or “make” refers to is how proportionate was the diamond cut, which is determined by the diamond cutters. GIA grades the cut of the grade and this cut can range from Excellent, Very Good, Good, Fair, and Poor. This cut grade was recently introduced by GIA in 2006. The cut grade determines the brightness, fire, and dispersion of the light that reflects off the diamond. The better cut diamond you may have the more fire, and dispersion of light it will reflect. Keep in mind buying an “excellent” cut grade diamond will most likely come with a premium price, both in the wholesale and retail markets, as these are some of the most sought after stones today.
Cut can easily be one of the most important out of the 4 c’s but also the most difficult to detect out right. It takes a well trained eye to determine the quality of the cut or make of the stone within a short amount of time. Of course we at Sehgal Diamonds can definitely guide you to detect the different standards of cut in any stone. A stone that is too shallow, which means the table of the diamond is too wide, can have light leak through different parts of the stone rather than the bottom of the stone. In every stone if it is a perfectly cut diamond the light will come through the top of the diamond and leak from the bottom. However if the stone is too “shallow” or too “deep” or has a “heavy” make this is not true, and your stone will not have the brilliance and beauty it should! To really learn about cut , one should learn about the diamond anatomy and terms as shown below. So when you are the market for diamonds you are fully aware of how a diamond is made and will be more than capable to “dissect” the diamond yourself!
Here are some diamond vocabulary which help explain the diagram better:
Table: The top and flat part of a stone. It’s largest facet of the diamond. Generally if the table is to wide, the diamond will usually turn out to be shallow. If the table is too small the diamond will be deep. A good table measurement is usually around 53% – 62%
Depth: The depth is the measurement from the table of the diamond to the culet (which is the bottom most part of the diamond). Generally if the table is too large the stone does not come out as deep or maybe shallow. If the table is too small generally the diamond is to deep. The depth of the stone is a large factor in determining the quality of the cut of your diamond. I would say a good depth would typically be around 59% – 62.5%
Culet: The culet typically refers to the bottom most part of the diamond. A culet is a small facet on the bottom of the diamond and typically was used to protect the diamond from chipping. Most modern cut diamonds have no culet or a very small culet. They are rarely used today.
Crown: The crown or crown angle are the facets that slope right beneath the table and connect to the girdle of the diamond. An excellent or ideal cut diamond would have a crown angle typically from 33 – 35%
Girdle: The outer edge or the widest part of the diamond. The girdle forms a band around the stone. The girdle will vary from very thick to very thin and all in between. The girdle part of the diamond is typically where the diamond is held in a jewelry setting.
Pavilion: The pavilion refers to the bottom half of the diamond, below the girdle.
Polish: The polish grade applies to the final finish to the diamond. Sometimes the diamond was not polished well and can leave streaks or small blemishes on the outside of the diamond. The polish is graded from Excellent to Poor.
Symmetry: The symmetry of the diamond applies to the overall proportion of the cut. It is a good indicator of the overall CUT grade. Sometimes not all facets point correctly towards to girdle or other misalignments of the facets of a diamond could affect the grade for symmetry. The symmetry of the diamond is also graded from Excellent to Poor.