Quick guide to Diamonds

Here is a very brief guide to diamonds.

This information is necessary for understanding how diamonds are described on a GIA grading report.

A more detailed read is available on our Diamond Education page.

Color of a diamond

  • The color of a diamond is graded with an alphabetic letter starting at D.
  • D is the clearest and is completely colorless.
  • J diamonds have still only very very faint coloring.
  • D diamonds are extremely rare.
  • A diamond with more colour than a Z rating is called a fancy.
  • Fancies are rare.
  • Fancies can be all sorts of colors, such as vibrant yellow, red, pink, blue, green, orange, gray or black.
Clarity of a diamond
  • Small crystals or trace elements inside a diamond are noted on a grading report and the diamond is graded accordingly.
  • IF or FL=Internally Flawless or Flawless and are the rarest types.
  • Next comes VVS1=Very Slightly Included 1.
  • Diamonds that receive an SI1, SI2, I1, I2, or I3 grade may have inclusions that are visible to the unaided eye.

Cut of a diamond

  • The shape of a diamond is called the “cut”
  • Engagement rings can be made with a wide variety of cuts.
  • The most frequently chosen cut is “round brilliant”. It is a shape that has been mathematically engineered to achieve the highest possible sparkle.

Carat weight of a diamond

  • One carat is equal to 200 milligrams or 1/142 of an ounce.
  • 1 carat diamonds are considered ideal for engagement rings.
  • Those with ‘petite’ hands may prefer a half carat diamond.
  • Some engagement rings are much larger , like Elizabeth Taylor’s 33.19 ct which she referred to as “my ice skating rink”.

How big is a 1 carat diamond?

  • The diameter of a 1 carat diamond when cut into a round brilliant shape will be approximately 6.4 mm to 6.5 mm. The size of every diamond is detailed on its grading report.


The video above from GIA goes over this information.

As can be seen in the video below a J stone is still only very slightly colored.


This video compares a J stone which shows the most color, on the left to an I stone, and then compared to an H stone and then a G stone.

girl says, check out the videos on diamond education