What are the four Cs of diamond?

Perhaps you have heard the term “4Cs” , but, unless you are buying a diamond, you may not have delved into what that means and why it matters.

That’s why I’m here, to help.

The short version? The 4Cs set the standard for the quality of a diamond. They give us the information we need to make an informed and smart shopping decision. They describe the stone. When the GIA (Gemological Institute of America) developed these standards, it made it much easier to purchase a diamond without seeing it.

Since so many diamonds are shipped from mines and cutting centers abroad, the clear definitions established by the 4Cs represent a revolutionary moment in diamond history.
Because of the 4Cs, a buyer can make an informed purchase decision without ever seeing the stone.

The first C stands for cut

Cut is where a skilled lapidary (cutter) can influence a diamond’s beauty the most. Because diamonds are crystals, the symmetry of the cut is critical to its beauty. Well-cut diamonds deliver the dazzle – they sparkle and flash with brilliance and fire. The geometry of a diamond –  the angles at which the facets are cut, and the proportion and balance of the facets, all contribute to the beauty of the finished stone.

A fine lapidary can orient the cut of a stone to optimize beauty, weight, sparkle and minimize the effect of unwanted inclusions.

three detailed and multi-diamond gold and silver necklaces

The next C stands for carat

Carat indicates the weight of a diamond. For some people, the bigger the better, for others it’s the quality of the stone that’s important. For most of us ... all the Cs are important.

Another way to rate carats is with “points”. A 1ct stone is 100pts. A half-carat stone is .50pts., and so on. That allows cutters to be precise about diamond weights.

There are some diamond weights that are considered “sweet spots”. They are the sizes that hit the “ideal weight” for a fine diamond, and they start at one-half carat and go up by half-carat increments. You typically pay more for a diamond in a “sweet spot”.

An insider tip: If you are selecting a solitaire – in any of the sweet spots – go for a stone that is one or two points under the specific carat mark. For a one-carat stone, it would be a .97 or .98  To the naked eye it will look just like a sweet-spot diamond, but it will cost a whole lot less.

Big stones are very fashionable, but they can get very pricey. More and more consumers are mixing lab-grown diamonds with their mined diamonds, as lab-grown stones are typically more affordable and are indistinguishable to the naked eye.

I love them all!

The third C stands for color

Color is very much in the “eye of the beholder”. For centuries, the most sought-after diamonds were colorless or “white” diamonds. (They aren’t actually white although the white designation is frequently misused. They are without color or colorless.)

The GIA has very specific color designations (with the exception of the pinks, reds and blues). They start at “D” for colorless and go down in increments to finally land at “Z”, which is the most yellow in the acceptable grading scale.

Brown diamonds are the most prevalent and have been used for many years in industry. Over the last several decades, we have come to appreciate the beauty in them. Many are clear and bright with a warm appeal. When a diamond in the brown range is “gem quality” it is used in jewelry. We love our champagne diamonds and think that many of the “brown shades” are stunning!

While color is a matter of choice, it is also extremely helpful to have the color-grading system established by GIA to use as a definitive guide. We think it’s the best of both worlds.

a brown diamond turtle metal necklace

The last C stands for clarity

When it comes to diamonds, it’s really about the sparkle. It’s about crazy, rainbows-of-light that dance on your hand or your wrist. It’s about the fiery flashes that shine and twinkle at your ears ... it’s all about that dancing light.

Clarity is one of the most important Cs. An unclear diamond, a diamond with heavy or obvious inclusions, can’t sparkle like a stone with good clarity. I say good clarity because diamonds are made by massive geological forces ... we like to say Mother Nature ... and very few are perfect.

However, most inclusions in the jewelry you see offered at jewelry stores like JTV are minimal and can’t be seen just by looking at the piece. Light is able to bounce out with the dazzle we desire from diamonds.

Why do all 4Cs matter?

It wasn’t by accident that Robert Shipley, founder of GIA, developed the 4Cs. They are the key factors that determine whether – or not – people are happy with the diamonds they select. The 4Cs make us smart, informed consumers. We can make purchases with confidence, knowing exactly what we are purchasing.

It would be unacceptable for me to leave lab-grown diamonds out of our discussion. Lab-grown diamonds are measured by the same standards – the same 4Cs established by GIA. More consumers than ever before are looking closely at lab-grown diamonds and what they offer. Chemically, physically, and optically the same as the Mother Earth stone – they, too, deliver the dazzle in which we delight.

The 4Cs, when combined, give a clear picture of every diamond ever known or grown. They provide an information foundation on which we can build a solid understanding and appreciation of the diamonds we adore.

a gold, silver and rosegold, white diamond dangle necklace

Are there 4Cs or 5Cs?

A fifth C has been introduced to the world in recent years. It’s the C of Certification. And, while not official, it is meaningful. As technology advances, we learn more about the amazing diamond and certification becomes a factor. Due to the advanced equipment we use, we can see more deeply into each diamond, we can analyze each more thoroughly, and we can measure our diamonds more accurately.

The C of Certification tells us that a professional, trained and licensed to assess and grade a stone, has looked at the certified gem. It doesn’t mean that a certified stone is a better stone. It only guarantees that the diamond is what they say it is!!!

People assume that a certified stone is somehow better – and it often is – but most importantly, that certification is a tool of knowledge. It tells you precisely about the stone you are considering.

4Cs and a G?

I think that there ought to be another area of evaluation. I think we should have the Cs of quality, and a G. The G stands for Goosebumps.

When you see a diamond, when you slip on a piece of diamond jewelry, if it doesn’t make your heart sing, don’t buy it.
The most important measure of any gemstone is whether you’ll love owning it and wearing it. It’s whether you will be thrilled to show it to your friends and family. Your special diamond should give you Goosebumps of joy.

You are the expert in that area. No one else can measure that for you.


Misty Mills is a long-standing member of the JTV family. Her first hosting opportunity came in June 1997 selling Beanie Babies! Her love of all things that sparkle quickly came through and she started selling fine jewelry within a month.

Read more about Misty on her JTV host page.