Diamond Knowledge


Carat weight is simply the weight of a diamond and does not necessarily relate to size. Diamonds are weighed in carats, and one carat is equal to 1/5 of a gram. Diamond weights can also be expressed in points or percentages. Each carat is divided into 100 points; therefore, if a diamond is described as 53 points, the weight is 53% of a carat, or just slightly more than a 1/2 carat diamond.

The diamond market has defined several different "magic weights" for diamonds, which impacts the price. A "magic weight" is the weight at which the value, or cost, per carat of the diamond increases. For example, a diamond that weighs 0.98ct can have a significantly lower cost than one that weighs 1.00ct, with all other factors equal, because 1.00ct is a "magic weight". When shopping for a loose diamond, ask for the specific weight to verify that the price is relative to the exact carat weight.


To determine a diamond's clarity, gemologists view it under 10-power (10X) magnification, evaluating the diamond for inclusions. Inclusions or surface blemishes are natural "birthmarks," which most diamonds contain. The fewer and smaller the inclusions are, the less they will interfere with light passage through the diamond, and a diamond gets its beauty from how it reacts to light.

Therefore, the better the clarity, the more the value, and gemologists classify clarity using these eleven grades:


Flawless diamonds show no blemishes or inclusions when examined by a skilled and experienced grader under 10 x magnifications.

The following do not disqualify a stone from the flawless category.

  • An extra facet on the pavilion which cannot be seen face up.
  • Naturals totally confided to the girdle, which neither thickened the girdle nor distort its outline
  • Internal graining which is not reflective, white, or colored, and does not significantly affect transparency.


    Internally Flawless stones show no inclusions and only significant blemishes under 10x magnifications. Normally what separate Internally Flawless (IF) from Flawless (FL) stones are characteristics that can be removed by minor republishing (light surface graining is an exception)


    VVS diamonds contain minute inclusions that are difficult for even the skilled grader to locate under 10x magnifications. In VVS1, they are extremely difficult to see, visible only from the pavilion or small and shallow enough to be removed by minor re-polishing. In VVS2, the minor inclusions are very difficult to see.


    VS stones contain minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) for a trained grader to see under 10x magnification. Small included crystals, small feathers, and distinct clouds are typical.


    SI stones contain noticeable inclusions which are easy (SI1) to very easy (SI2) to see under 10x magnification. In some SIs, inclusions can be seen with the unaided eye.


    I-grade diamonds contain inclusions which are obvious to a trained grader under 10x magnification, can often be easily seen face-up with the unaided eye, seriously affect the stone's potential durability, or are so numerous they affect transparency and brilliance.

    I1 (Imperfect: Level 1)
  • Moderate effect on beauty or durability. This is the first grade at which an inclusion can be seen with the naked eye, or without the 10x magnification. This is also the most common diamond grade found in the retail market today.
  • I2 (Imperfect: Level 2)
  • Inclusions easily visible to the naked eye and has a severe effect on beauty or durability. An I2 diamond is noticeably different from an I1 diamond. The I2 grade is given to a diamond that has several or very easily seen inclusions in it.
  • I3 (Included: Level 3)
  • Several very visible inclusions and has a severe effect on beauty and durability. The lowest grade a diamond can receive and still be considered gem quality is I3, after which it becomes an industrial grade diamond. An I3would have extremely visible inclusions. Often an I3 diamond has inclusions that can seriously threaten the durability of a diamond.