The 4C’s and Diamond Certification
Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip.
For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, colour and cut. The majority of diamonds used in fine jewellery weigh one carat or less.
Diamond colour is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value.
GIA’s colour-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colourless, and continues with increasing presence of colour to the letter Z, or light yellow or brown. Many of these colour distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
Internal Inclusions or External Blemishes: Diamond Clarity
Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) – Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance
Cut is the factor that fuels a diamond’s fire, sparkle and brilliance.
Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the flashes of light, or sparkle, when a diamond is moved).
As a value factor, though, cut refers to a diamond’s proportions, symmetry and polish. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light.
For more information please see http://www.gia.edu/lab-reports-services/about-the-4cs/index.html
At Facet, our certified stones are usually above 0.50ct in carat weight. We are happy to send any diamond to be issued with a GIA cert upon request. ALL of our diamonds are guaranteed by us and come with a certificate for valuation detailing the exact properties of what you are purchasing.