First things first check when the report was issued. High quality diamonds should be re-assessed every 5 to 10 years. Although the diamond is the hardest material on earth, it can still be chipped or cracked. Large chips and cracks can be seen with the naked eye, and so fine diamonds should be visually inspected every so often. But the real test is under a microscope. Chips and cracks can affect the clarity grade of the diamond and decrease the value of the stone significantly.
Also, make sure that the report is genuine and issued by a authoritative laboratory. The most famous institutions that issue reports are the GIA and the AGL in the United States. Also make sure that the report states that the gem itself is a diamond. This may seem silly, but a diamond grade report that does not contain the word diamond should be raising red flags.
Now that the preliminary inspections are done, move on to the exciting parts of the report, the specifications of the diamond itself. The most widely used measurement of the diamond’s worth is the weight, denoted by the carat unit of measurement. Along with the carat the dimensions should also be listed and recorded. The dimensions of the diamond also serve to identify the diamond itself as the accuracy of the measurement is very precise. It is quite rare to find two diamonds of equal carat weight and the exact same measurements down to the millimeter. Also if a diamond was ever chipped and repaired, the resulting change in measurements will reveal that the diamond had been altered with.
The dimensions will also indicate whether the diamond is out-of-round or not. Out-of-round diamonds are less perfectly round and are valued much less than well-rounded diamonds that are cut more perfectly round. Well-rounded diamonds deviate only about 0.10 millimeters in a one carat stone, and if the deviation is greater than the 0.10 millimeter then it is called out-of-round.
The depth and table percentages are part of the most important attributes that determines the diamonds beauty. The depth table percentages helps dictate how the cut of the diamond is proportioned and so how much light will be reflected within the gem and back out to the eye. The depth percentage should be at a range of 57% to 64% and the table percentage should be at a 53% – 64% range.
Of course we also have the clarity of the diamond that greatly influences the price. The clarity of the diamond ranges from flawless to very slightly included to imperfect. The clarity refers to tiny imperfections in the gem, often not visible to the naked eye, that exist within the diamond. This is because other elements or materials can become trapped while the diamond was being formed. Other causes of clarity imperfection are on the outer layer of the diamond caused often by tiny chips.
Another important factor is the color of the diamond. Yes, diamonds are supposed to be clear/white but diamonds can come in a variety of colors. Some colors, like blue or pink, can drastically increase the value of the diamond. The color variations occur not because of impurities as in the clarity, but often because the diamond, which is made of carbon atoms tightly arranged together, can also have very small traces of other elements within it. For example, Nitrogen is the most common element found in diamonds, other than carbon of course, and it can cause the diamond to have a yellow to brown tint. Other and less common reasons for color variation is irradiation, causing a green coloration, and what scientists called plastic deformation, which refers to a slight variation in the structure and placement of the carbon atoms and can cause a pink to red coloration. The rarities of the colors are ordered as follows from most common to rarest: Yellow, brown, colorless, blue, green, black, pink, orange purple and red.
So make sure to look over the report carefully when shopping around for diamonds. There are many factors that affect the value of the diamond itself, often many that are not visible to the naked eye.
