Special Diamond Cuts Diamond Shapes Branded Diamond Fancy Shapes
THE 4 C'S DIAMONDS - CUT CARAT COLOR CLARITY
CHARACTERISTICS
  • In the past, the 4 most popular factors (used to grade a diamond) were cut, carat, color and clarity. (It should be noted that De Beers introduced this set of criteria in 1939 in order to give retailers and consumers a set of reference criteria when evaluating diamonds.)

  • Nature dictates the characteristics of color, clarity and carat, while the cut is directly influenced by the cutting and polishing process.


CERTIFICATES
  • Grading Certificates consider these characteristics to be very important, but a few certificates are also available with more updated cut specifications.

CUT
  • Cut refers to the angles and proportions created in transforming a rough diamond into a polished diamond.

  • A well-cut diamond will reflect light internally from one mirror-like facet to another, dispersing it through the table of the stone.

  • Cuts that are too deep or too shallow lose or leak light through the side or bottom (affecting the diamond's brilliance).

* Facets:
Diamond cutting requires great skill and training, because the diamond polisher-cutter must polish tiny surfaces known as facets (crown, culet, table, girdle, and pavilion) onto the rough diamond in a very precise manner.

  • The facets, when arranged in precise proportions, will maximize the fire, life, and brilliance of a diamond.

  • It should be noted that to cut a diamond perfectly, a diamond polisher will often need to cut away more than 50% of the rough diamond thereby seriously affecting the yield of the rough (the consideration being for beauty not for carat weight).

  • Ideal cuts and hearts and arrows diamonds are examples of diamonds that have been cut for maximum brilliance and light performance and not for weight retention.

Depending on the facet design, cutting styles are categorized into 3 basic types:
step-cut, brilliant-cut, and mixed-cut.

  • Until some of the new patented branded cuts, brilliant cuts were thought to reflect the most light.

  • Step-cuts have rows of facets. (The emerald is an example of this cutting style.)

  • Mixed-cuts have both step and brilliant-cut facets. (One of the most popular is the princess.)

* Shape:
Cut may also refer to the shape of a diamond: round, emerald, heart, marquise, princess, lily cut, caressa, crisscut, etc.

* Accuracy + Symmetry + Facet Design = Light Performance
  • Perhaps, the most exciting new feature (as seen in a number of grading reports or with separate certification) is the evaluation of the performance of light of a diamond's cut. Light performance is a function of facet design, accuracy, and symmetry.

CARAT
  • A carat is a measure of weight. (Carat weight is one of the factors to take into consideration when choosing a diamond.)
  • A carat is sometimes confused with size (diameter/depth) even though it is actually a measure of weight.

(Lili Diamonds also does calibrated measurements of diamonds for jewelry designs and layouts.

** Carat with a C should not be confused with Karat with a K **

  • Carat (with a C) is for diamonds. Its source of reference is the carob seed.

  • The term carat is a derivative of the word carob. Carob seeds, which are uniform in weight, and because of their accuracy were used as a reference for weighing diamonds (during the days of the caravan travelers). One carob seed equaled one carat.

  • One carat can also be divided into 100 "points." (A .75 carat diamond is the same as a 75-points or a 3/4 carat diamond.)

  • The spelling of Karat (with a K) is used for measuring the purity of gold and is the equivalent of 200 milligrams.

COLOR
  • Diamonds are graded for a wide range of colors on a color scale. Established by the Gemological Institute of America - GIA, the scale ranges from D (colorless) to Z, and is used as a reference color scale by most gemological laboratories.
  • In the past, colors were classified with more interesting names including commercial, wesselton, top light brown, silver cape, cape, off-white, river, and many more.
  • Today some diamonds are classified with more descriptive names such as vivid yellow, fancy yellow, vivid pink, champagne, coffee, smokey, amber, and cognac.

> Natural Fancy Colors:
  • Natural fancy colors that are found in nature include: pink, blue, green, yellow, brown, orange and, very rarely, red.
    These are incredibly rare and valuable.

  • Some famous fancy color diamonds include the Heart of Eternity diamond and the De Beers diamond.

CLARITY

  • Rough diamonds have natural blemishes (inclusions) in their internal structure which are formed by minerals or fractures while the diamond is forming in the earth.

  • When a diamond is polished, light enters it and is subsequently reflected and refracted out.

  • If there is anything disrupting the flow of light in the diamond, such as an inclusion, a proportion of the light reflected will be lost.

  • Because most inclusions are not visible to the naked eye unless magnified, to view inclusions, trained gemologists use a magnifying loupe (to see a diamond at 10x its actual size).

  • A grading method that rates diamonds on the size, nature, and positioning of the inclusion requires an expert eye to assess.

  • Clarity descriptions range from IF (Internally Flawless - no visible characteristics under magnification) to I (Included - characteristics visible with the naked eye). VVS is Very, Very Slightly Included and to VS is Very Slightly Included.

  • Inclusions appear as different shapes, such as crystals, clouds or feathers. (The majority of these natural birthmarks are invisible to the naked eye, yet they affect the way light is reflected and refracted within the stone. Diamonds that have no inclusions under magnification are extremely rare and are rated FL for flawless.)

REFERENCES:
  • 4C's information reference sourced from The De Beers Group corporate website. www.debeersgroup.com/debeersweb/Diamond+Industry/The+Four+cs/

  • Performance of Light Information: Lili Diamonds.