Diamond Grading Tools

• Diamond grading tools help establish the value of the diamond. diamonds black 1 image by Renato Francia from Fotolia.com

  Diamonds are graded on their color, clarity, cut and carat weight, also known as the 4C's of diamond grading. The combination of these four guidelines are what determines the price and value of the diamond. Understanding and measuring each of these parameters requires knowledge, experience and the right set of tools.

Master Grade Set

• The less color, the greater the value of the diamond---a colorless diamond will have the most value. Color is compared to a master grade set, which is a set of diamonds that have already been graded. The tool allows the grader to identify the diamond's color according to the diamond in the master set it most closely matches. This process is accurate but can be time consuming and so graders will declare the color of smaller stones by grading in batches or ranges. Master grading sets can be purchased from gem supply companies, a typical set contains gem grades E through N although other set combinations are available. Sets start at $200.

Magnification

• Grading clarity is the process of identifying the number of inclusions (items that block light like other minerals, voids or fractures) the diamond contains and comparing that against the Gemological Institute of America's clarity grades. Graders assign clarity using magnification at 10x and use both a 10x loupe and a 10x gemological microscope. The loupe, also called triplet, is small, inexpensive and easy to carry and comes in a variety of styles including loupes that are glasses or clip onto glasses. Gemological microscopes allow for deeper investigation into the inclusions in the stone. Cost of a 10x microscopes starts at around $300 and can rise into the $3000 to $5000 range.

Cut Estimator

• Graders must identify a diamond's parameters which include table size, crown angle, star length, and pavilion angle to grade the cut. Digital proportion analyzers work by using a camera and software that measure and photograph the diamond from all angles by rotation. The software attached to the analyzer produces a report that grades the diamond on cut.

  An eye piece that attaches to a gemological microscope can also help determine many of the proportions. These proportion analyzers can be purchased as an attachment to the microscope.

Electronic Scales

• Electronic carat scales are used to determine carat, which is the weight of the diamond. A single carat is equal to one fifth of a gram or 0.2 grams. Also known as jewelry scales, a sturdy, reliable scale can be found in the $200 to $300 range.