Determining the Value of Gemstones Using The 4 C's
When determining the quality of various gemstones, especially diamonds, there are 4 different factors that contribute to the overall value of a given gemstone. Those 4 factors all begin with the letter C, and while they are most often used to help value diamonds, they apply to other gemstones as well. We will be referring to these 4 Cs using diamonds from here on out, but just know that all of this information also applies to virtually any gemstone.
The 4 Cs are:
It wasn't until the middle of the 20th century that the GIA (Gemological Institute of America) created these standards of judging diamonds, which later became universally adopted by all. Before this, there was no universal standard by which to objectively judge the value of a diamond, and instead it was all subjective. The introduction of the 4 Cs created 2 new breakthroughs for assessing diamonds - the first being that there was now a universal vernacular that everyone could adopt to be able to uniformly communicate about diamond quality; secondly, diamond shoppers, provided they are careful to educate themselves about the 4 Cs, could now also know exactly what kind of diamond they are getting for the money they are spending. Now let's take a closer look at each C so we can understand them better.
Carat - This one is perhaps the most simple of the 4 Cs. Carat weight is a measurement used to determine how much a diamond weighs, which tells you how big or how small a diamond is. There is also a smaller unit than a carat, which is called points. Anything under a carat will be referred to by how many points it is, i.e. a .5 carat diamond could be called a 50 point diamond.
Color - This one is actually a little counterintuitive, as when it comes to diamonds, less color means more value. This is not necessarily true of other gems. The color is graded a letter grade system from D to Z, with D being the most colorless, and Z being the least. Many of the colors are subtle enough that an untrained eye cannot tell a difference, but the surest way to determine the color grade is to view the stone under controlled lighting conditions, and comparing it to a master stone.
Clarity - Diamond clarity refers to how free of inclusions and blemishes a given stone is. Quite simply, the fewer the blemishes, the more valuable. Inclusions are internal, while blemishes are external. Both are the natural byproduct of the fact that diamonds are nothing more than carbon subjected to extreme amounts of heat and pressure deep under the earth's surface. Evaluating these inclusions and blemishes comes down to examining how many there are, how big they are, the position they are in the stone, etc. There is no diamond perfectly free of inclusions, but the closer it comes to that, the more valuable it will be.
Cut - Cut is all about how a diamond is cut, which is important because of how the cut allows the light of a diamond to really shine through. When we talk about a diamond's cut, it's what we often refer to as its shape, such as round or oval-shaped. However, what the cut is really all about is how the cut allows light to refract and radiate through the stone. It's all about the stone's relationship with light. It takes very delicate skill to properly cut a diamond so that it will deliver that beautiful sparkle everyone expects from it. Round is the most common cut. Of all the 4 Cs, cut is the most complicated one to analyze.
And there's is what can be considered just a brief overview and introduction into the world of diamond/gemstone evaluation, which, although there are many technical factors at play, it can also be thought of as more of an art form than a science!
For further reading, check out GIA's guide they put together: https://4cs.gia.edu/en-us/4cs-diamond-quality/