Diamond Education

Diamond Buying Guide

The Robust Diamonds Education Guide is designed to give you the tools and information you need to properly evaluate diamond quality and value with confidence. Every diamond certified by the Diamond labs undergoes a thorough, independent evaluation, which affect the diamond's price. based on 4 C's (Carat Weight, Cut, Color, Clarity).

Cut refers not to a diamond's shape (e.g. round, oval, pear, etc.) but to a diamond's proportions, symmetry and polish. The beauty of a diamond depends more on cut than any other factor. Though extremely difficult to analyze and quantify, diamond cut has three primary effects on appearance: brilliance (the brightness created by the combination of all the white light reflections from the surface and the inside of a polished diamond), fire (the dispersion of light into the colors of the visible spectrum, seen as flashes of color), and scintillation (the flashes of light and dark, or sparkle, when a diamond or light source is moved).
Labs grades diamonds on a scale of D (colorless) through Z (light color). All D-Z diamonds are considered white, even though they contain varying degrees of color. True fancy colored diamonds (such as yellows, pinks, and blues) are graded on a separate color scale.The less body color in a white diamond, the more true color it will reflect, and thus the greater its value.
The GIA diamond grading scale is divided into six categories and eleven grades. The clarity categories and grades are:
  • Flawless category (FL) diamonds have no inclusions or blemishes visible under 10x magnification.
  • Internally Flawless category (IF) diamonds have no inclusions visible under 10x magnification, only small blemishes on the diamond surface.
  • Very, Very Slightly Included category (VVS) diamonds have minute inclusions that are difficult for a skilled grader to see under 10x magnification.
  • The VVS category is divided into two grades; VVS1 denotes a higher clarity grade than VVS2. Pinpoints and needles set the grade at VVS.
  • Very Slightly Included category (VS) diamonds have minor inclusions that are difficult to somewhat easy for a trained grader to see when viewed under 10x magnification. The VS category is divided into two grades; VS1 denotes a higher clarity grade than VS2. Typically the inclusions in VS diamonds are invisible without magnification; however, infrequently some VS2 inclusions may still be visible. An example would be on a large emerald cut diamond which has a small inclusion under the corner of the table.
  • Slightly Included category (SI) diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification. The SI category is divided into two grades; SI1 denotes a higher clarity grade than SI2. These may or may not be noticeable to the naked eye.
  • Included category (I) diamonds have obvious inclusions that are clearly visible to a trained grader under 10x magnification. Included diamonds have inclusions that are usually visible without magnification or have inclusions that threaten the durability of the stone. The I category is divided into three grades; I1 denotes a higher clarity grade than I2, which in turn is higher than I3. Inclusions in I1 diamonds often are seen by the unaided eye. I2 inclusions are easily seen, while I3 diamonds have large and extremely easy to see inclusions that typically impact the brilliance of the diamond, as well as having inclusions that are often likely to threaten the structure of the diamond.

Virtually all diamond cuts sold for use in jewelry are one of ten round or fancy diamond shapes. The most popular diamond shapes are: ROUND, PRINCESS, OVAL, MARQUISE, PEAR, CUSHION, EMERALD, ASSCHER, RADIANT, HEART.
Before being purchased, many diamonds, and all Robust Diamonds are sent to a third party laboratory for a comprehensive evaluation; a process known as diamond certification. A reputable lab is one staffed by professional gemologists who specialize in diamond grading. Each diamond certificate issued is uniquely numbered, and corresponds to one individual diamond. From that point forward, the diamond and certificate (laminated to prevent tampering or damage) will travel together from seller to buyer.