A Summary of the Diamond 4 C's
A diamond is graded based on four factors. They're carat weight, cut, color and clarity.
Let's start with carat weight. Carat weight is the overrated value determining factor for a diamond. A diamonds weight is represented in the 'carat' unit measurement. One carat is equal to 0.2grams. The abbreviation for carat is 'ct'. The basic concept is; a diamond of a heavier carat weight, considering all other factors equal is certainly more valuable than a diamond of a lesser carat weight. Larger diamonds are rarer than smaller ones therefore, a one carat diamond is more expensive than purchasing four 0.25ct diamonds, considering all other things equal.
The cut is the underrated 'C' when most consumers are purchasing diamonds. The cut has a tremendous effect on a diamonds fire, brilliance and scintillation. The cut refers to the proportions, symmetry and polish of the diamond. The important cut factors to consider when buying a diamond are the table size, total depth percentage, crown angle, girdle thickness, and culet size. The goal is to purchase a diamond that is cut well enough for the light to enter through the table, bounce around the pavilion or bottom of the stone and leave through the table again. We do not want light leakage through the pavilion or at least we want to minimize it. The more light leakage, the less lively the stone will look.
Diamonds also come in an array of colors and these different colors are extremely relevant to the value. Most loose diamonds purchased today are classified in what is called the normal color range created by the
Gemological Institute of America. This includes diamonds ranging from completely colorless to light yellow and light brown. Colorless stones are the rarest which in turn mean they are the most valuable of diamonds. The recognized color scale starts at the letter 'D'(colorless) and goes down to the letter 'Z'(light yellow or brown). Please note, fancy colored diamonds are a whole other apple.
Diamonds have what are called clarity characteristics or imperfections. If the diamond imperfection is located on the interior of the stone, it's called an inclusion and an imperfection located on the surface of the diamond is called a blemish. Both inclusions and blemishes affect the value. Inclusions have more of an effect on the value than blemishes because blemishes are relatively easy to polish out and usually have less of an affect on the fire, brilliance and scintillation. The clarity grade is determined on how many and how visible an inclusion or inclusions are to a trained gemologist, using a 10x loupe. There is a world wide clarity grading scale starting at the highest grade being 'Flawless' and ending at the lowest grade being 'I' clarity. A diamond that is graded Flawless is exactly that, meaning the diamond has no inclusions and no blemishes. A flawless diamond is extremely rare and many people in the diamond trade will not see a flawless diamond in their lifetimes. An 'I' clarity graded diamond contains inclusions visible to the naked eye which make these stones the least valuable of diamonds used in jewelry. Most diamonds sold at the retail level will have inclusions, some more than others.