Key Factors for Determining the Value of a Diamond

The key to a diamond’s value is its rarity, and no two diamonds are alike. Rarity is determined by a diamond’s unique characteristics as measured by the Four Cs: Cut, Color, Clarity and Carat Weight.


The Gemological Institute of America (GIA) Color Scale extends from D (colorless) to Z (light yellow or brown). Although many people think of gem quality diamonds as color-less, truly colorless diamonds are actually very rare. Most diamonds used in jewelry are nearly colorless with tints of yellow, brown, or gray. Color grades are determined by comparing each diamond to a master set. Each letter grade represents a range of color and is a measure of how noticeable a color is.

GIA Color Scale:  color scale diamond

diamond clarityClarity

The GIA Clarity Scale includes eleven clarity grades ranging from Flawless to I3. Because diamonds form under tremendous heat and pressure, it is extremely rare to find a diamond that lacks any internal characteristics (called inclusions) and external blemishes. These characteristics are a byproduct of its formation.


GIA Clarity Scale:  clarity diamond


diamondA polished diamond’s beauty lies in its complex relationship with light: how light strikes the surface, how much enters the diamond, and how, and in what form light returns to your eye.

The result is a magnificent display of three attributes. Brightness is the combination of all white light reflecting from the surface and interior of a diamond. Fire describes the scattering of light into its spectral or rainbow colors. Scintillation describes the flashes of light you see when the diamond, the light, or the observer moves.

A polished diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with fine proportions, symmetry, and polish optimize their interaction with light, and have increased brightness, fire, and scintillation.

Carat Weight

One carat equals 200 milligrams or 1/5 of a gram in weight. For diamonds under one carat, each carat is divided into 100 points — similar to pennies in a dollar. 0.75 ct. = 75 points, 1/2 ct. = 50 points.