The FIVE C’s of Diamonds

You’ve probably heard of the Four C’s of diamonds, Carat, Color, Cut, and Clarity. These have been the main discussion points between diamond buyer and seller for centuries. Would it surprise you that the average person could not tell the difference in minor variations in any of these attributes, even if the diamonds were examined side-by-side under a microscope? That’s okay, because the fifth C, Certification means an independently trained gemologist has already done the work for you.

Let’s quickly cover the original Four C’s:

  • Carat – Refers to the weight of the diamond 1 carat equals 0.2 grams.
 Diamonds under a carat (say .99 carats) tend to price disproportionately less than diamonds of one carat or higher (say1.0 carat).
  • Color – Color grades are measured from D to Z. D is completely void of any color and is the most valuable, and Z has a noticeable yellow tint, making it less desirable.
  • Cut – Not to be confused with a diamond’s shape such as round, oval, etc. Cut refers to the polish and symmetry of the facets’ (a facet is each of the many tiny flat sides of a diamond – a round diamond has 57 facets for example) proportions on the surface of a diamond. The “cut scale” is measured as: excellent, very good, good and fair. Cut, more than any other factor, determine’s a diamond’s beauty.
  • Clarity – While it may be easier to determine a misshaped diamond (cut) it is far more difficult to measure an unclear one. When a gemologist examines a diamond, he uses special tools to see internal flaws (aka inclusions). A diamond that is graded “internally flawless” (IF) without any blemishes, is almost unheard of and worth a fortune. At the other end of the scale is “I3,” which means that inclusions can be seen with the naked eye. The scale then is from FL (flawless) to I3, (easily observable to the naked eye):
    • FL (flawless);
    • IL (internally flawless);
    • VVS1, VVS2 (inclusions are very, very slightly included and discernible under 10x magnification);
    • VS1, VS2 (inclusions are very slightly included and discernible under 10x magnification, but characterized as minor);
    • S1, S2 (flaws are slightly visible to the trained eye, without magnification); and
    • I1, I2, I3 (easily discernible to the naked eye).


The fifth, and possibly most important C, Certification!

GIA SCreenshot

One of the greatest contributions to the diamond industry was the advent of diamond certifications. For a nominal charge your jeweler can have his diamond inventory certified before you walk in the door (and most do!). Color, cut, clarity and carat are all confirmed by a reputable third party such as GIA, who is entirely focused on protecting and enhancing its’ reputation in the buyer community and disinterested in if their grading upsets the jewelers. There are four reputable diamond grading labs and one so-so. The four biggies, in order of reputation, are:

  • Gemological Institute of America (GIA),
  • American Gem Society (AGS),
  • Hoge Raad voor Diamant (HRD),
  • International Gemological Institute (IGI), and
  • European Gemological Laboratory (EGL).


In reality most diamonds are graded by GIA or AGS. If the grading comes from one of the others you should be suspicious. If the diamond comes from EGL, run, don’t walk, from the jeweler’s office! EGL has been known to grade in favor of the jeweler, not the customer and as a consequence is considered much looser. James Allen and Zoara will not stock any diamonds certified by EGL. They limit their inventory to diamonds certified by GIA and AGS.

So that’s it for day two. Tomorrow we’re going to discuss “florescence.” A term used to describe the reaction of trace minerals that cause a “glowing” effect on the diamond under a UV light.