Getting to know diamonds
The 4Cs, plainly.
Four words you will see often: cut, color, clarity and carat. Start with what each describes, then bring your questions back to the individual diamond.
Read the guide
Cut: how a diamond handles light
Shape names the outline, such as round or oval. Cut describes the arrangement and quality of the facets, which affect the light you see as brightness, colored flashes and sparkle.
GIA’s Excellent-to-Poor cut scale is designed for standard round brilliant diamonds in the D-to-Z color range. Do not apply that scale automatically to every shape or report. Ask to see the individual stone in ordinary lighting as well as its report.
Color: reading the scale
GIA’s D-to-Z scale runs from colorless at D to light yellow or brown at Z. Graders compare diamonds under controlled conditions. Fancy-colored diamonds use a different grading approach.
Use the stated grade as a starting point, then look at the piece you are considering. A screen image is not a substitute for a laboratory color assessment.
Clarity: details inside and on the surface
Clarity considers internal features, called inclusions, and surface features, called blemishes. GIA evaluates their size, number, position and other characteristics under 10× magnification.
A clarity grade is not a promise about what you personally will notice without magnification. Ask about the actual diamond rather than assuming every stone with the same grade will look identical.
Carat: weight, not dimensions
One carat equals 0.2 grams and is divided into 100 points. Carat measures weight; it does not give you the diamond’s width or length.
Compare measurements in millimeters alongside weight. For jewelry with several stones, ask whether the listed weight describes the center stone or the total across the piece.
Bring these questions to your shortlist
Keep the comparison specific to the piece you would receive.
- Is the diamond natural or laboratory-grown, and are any treatments disclosed?
- Is a laboratory report available for this stone? Which laboratory issued it, and when?
- What are the stone’s measurements, the setting details and the care instructions?
- Can you view the actual piece and confirm the price and applicable return terms?
Sources reviewed . General education; check the details and care instructions for your individual piece.