Gemstones and Jewelry



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Chocolate Diamonds
Colored Diamonds
Diamond Guide (The 4Cs)
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Emerald Guide
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Opal Guide
Peridot Guide
Ruby Guide
Sapphire Guide
Tanzanite Guide
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Karat Gold Jewelry
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Diamond Guide - Diamond Grading Scale

What are the 4Cs of Diamond Quality and
Why Are They Important When Buying Diamond Jewelry?

The four Cs of diamonds stand for clarity, cut, carat and color.  The Gemological Institute of America (GIA) established the International Diamond Grading System, and the subsequent 4Cs, in order to provide a means by which the diamond industry could objectively evaluate diamonds on a consistent basis.

The rating a diamond receives on each of these 4Cs is what ultimately determines the value of the diamond(s) in your diamond jewelry.


Diamond Clarity 

Diamond clarity refers to each diamond’s unique characteristics (flaws).  As flawless diamonds are very rare, don’t be surprised to find that the gorgeous diamond jewelry you admire have inherent flaws – virtually all diamond jewelry does.  Internal flaws are called inclusions and external flaws are called blemishes.

Under the GIA Diamond Grading System, diamonds are issued a clarity rating ranging from Flawless to Included:

Flawless Diamond (F) – No inclusions or blemishes visible under 10x magnification.

Internally Flawless Diamond (IF) – No inclusions and only minor blemishes under 10x magnification.

Very, Very Slightly Included Diamond (VVS1, VVS2) – Inclusions are difficult to see under 10x magnification.

Very Slightly Included Diamond (VS1, VS2) - Minor inclusions visible under 10x magnification.

Slightly Included  Diamond (SI1, SI2) – Inclusions noticeable under 10x magnification.

Imperfect Diamond (I1, I2, I3) – Inclusions are obvious under 10x magnification and may affect brilliance and transparency of the diamond.

Clarity-Enhanced Diamonds

The clarity of a diamond can be enhanced by use of a laser drill (to drill out inclusions in the diamond) or by means of fracture filling (filling tiny cracks with a clear glasslike substance).  Laser drilling does not affect the strength or durability of the diamond itself.  Fracture filling results in repairs that can erode or darken over time and a fractured-filled enhanced diamond is does not have the durability or strength usually associated with diamonds.

As with gold plated jewelry versus karat gold jewelry, there is nothing wrong with purchasing clarity-enhanced diamond jewelry provided the condition of the diamond is fully disclosed to you prior to your purchase and the purchase price reflects such enhancement. 

Diamond Cuts

The cut of a diamond is the only true aspect of a diamond’s value that can be influenced by man.  It is the diamond cutter's responsibility to choose a diamond cut that will bring forth a stone's inner fire, brightness and sparkle while eliminating or minimizing any flaws the diamond may have.   The majority of diamonds cut for diamond jewelry manufacturing purposes - about 75% - are cut into round brilliants.  All other cuts (marquise, emerald, etc.) are known as fancy shapes or fancy cuts.

Under the GIA Diamond Grading System, diamond cuts are rated on a scale from Excellent to Poor.

Diamond Carat Weight 

Okay, ready for some math?  Here we go:

A gemstone’s weight is measured in metric carats, and a carat is equal to 0.2 grams.  Each carat is divided into a scale of 100 points.  In the same way that fifty cents equals a half dollar, a 50 point diamond is equal to carat, a 25 point diamond would be equal to a quarter carat, and so forth.

Although our natural inclination might be to think, “The bigger the  diamond, the more valuable the stone,” keep in mind that a diamond’s value is based on its grade using the 4Cs scale.  It is absolutely possible for a diamond with a small carat weight but with excellent clarity and cut to be more valuable than a larger diamond with less clarity and a lesser cut.

Diamond Color Scale 

Most diamonds used in diamond jewelry are considered near colorless with either yellow or brown tinting.  True colorless diamonds are very, very  rare and therefore quite valuable.

GIA’s Diamond Grading System grades diamond color on a letter scale of D (colorless) through Z ( light yellow or brown).

D, E, F - Grades of colorless diamonds.  D is the highest grade.

G, H, I, J - Grades of near-colorless diamonds.

K, L, M - Grades of faint yellow diamonds.

N, O, P. Q, R, S-Z - Grades of very light yellow diamonds.

Frankly, it's highly doubtful that a layperson will see a great deal of difference between, say, a G color diamond and an I color diamond with the naked eye.  While diamond color and clarity is vitally important from a gemological standpoint, buying a slightly included diamond on the lower end of near-colorless is probably not something that would be detectible in everyday life unless you run with a crowd that carries its own bright lights and jeweler's loupes.  Making a bit of a compromise on clarity and color, however, can mean you're able to afford a larger diamond.  It all depends on the end result you're after and, of course, we all want to buy the best we can afford.

What is a Certified Diamond? 

Buying a certified diamond jewelry means your diamond’s quality has been certified in writing by an independent gemological laboratory.  The most well-known certifications come from  the Gemological Institute of America (GIA – headquartered in Carlsbad, California); the American Gem Society (AGS – headquartered in Las Vegas, Nevada); the International Gemological Institute (IGI – headquartered in Antwerp, Belgium);  and European Gemological Laboratories (EGL – headquartered in New York, New York).

Need more information?  Visit our Jewelry Reference Links page.

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