Home >> Science & Nature >> Rocks & Minerals

The Characteristics of a Perfectly Cut Brilliant Diamond

Thanks to a combination of carbon, intense heat, extreme pressure and time, the Earth's mantle occasionally yields a rare treasure: diamonds. Diamond evaluation is both an art and a science. In an attempt to standardize the way diamonds are assessed value, the Gemological Institute of America (GIA) has developed criteria for accurately and consistently evaluating diamonds. These criteria are centered around the four C's: cut, color, clarity and carat.

Cut
- "Cut" refers to a diamond's proportion, symmetry and polish. The GIA's Cut Scale is divided into five sections: Excellent, Very Good, Good, Fair and Poor. Criteria for determining where a diamond falls on the Cut Scale include scintillation (sparkle), contrast (light vs. dark), pattern (how the light and dark are positioned), weight ratio (weight vs. diameter), durability (width of girdle and presence of inclusions, or impurities), polish (presence of scratches or chips) and symmetry (outline of the stone). A brilliant cut diamond is given a Poor rating if it shows little brilliance and has poor proportions. A perfectly cut brilliant diamond would have an Excellent rating, showing high scintillation, an even pattern of dark and light, a wider girdle and no inclusions or scratches.
Color
- In general, the more colorless a diamond is, the more value it has. The GIA's Color Scale runs from D to Z, with D being colorless and Z showing light yellow color. These color variations can be very subtle. A perfectly cut brilliant diamond would have a D color rating.
Clarity
- Clarity refers to a diamond's internal impurities (inclusions) or external impurities (blemishes). The International Diamond Grading System assesses diamonds as flawless (FL), internally flawless (IF), very very slightly included (VVS1 and VVS2), slightly included (SI1 and SI2) or imperfect (I1, I2 and I3). A perfectly cut brilliant diamond would fall in the FL or IF range, but it is important to note that completely flawless diamonds are exceedingly rare. In fact, most jewelers have never seen one.
Carat
- Carat weight is absolute and easy to assess --- the diamond is simply weighed. One carat is equivalent to 0.2 grams. Carats are divided into 100 points; for example, a half carat diamond is 50 points. The characteristics of a perfectly cut brilliant diamond vary depending on its cut, color and clarity. A perfectly cut brilliant three-carat diamond will simply be larger than a one-carat diamond with the same cut, color and clarity ratings.

Rocks & Minerals