The clarity rating of a diamond is based on the number and visibility of inclusions (tiny pinpoints, markings, and clouding) within the diamond. These inclusions can affect the overall appearance of the diamond. There are two types of flaws that can occur in natural diamonds: inclusions, which are internal flaws, and blemishes, which are external or surface flaws. In general, diamonds with fewer inclusions and blemishes will have a higher clarity rating, which increases their brilliance and value.
Expert tip 1: When it comes to diamonds with a VS1 grading or higher, it is necessary to use magnification to see the impurities. Choosing a diamond with a VS1 or higher grading is a subjective quality decision that goes beyond what can be seen with the naked eye. Larger diamonds with these higher grades are rarer and therefore command higher prices, and they also tend to be a better investment.
Expert tip 2: Although diamonds with an SI1 or SI2 grading are generally not considered “eye-clean” (i.e., free of visible impurities), some SI1 diamonds (up to 20% of cases) may appear to be eye-clean due to the impurities being light in color or scattered. This number falls to just 5% for SI2 diamonds. The most common types of impurities found in diamonds are feathers and crystals.