ダイヤモンドの4C

Every diamond varies slightly from the next and has its own individual distinguishing characteristics. Laboratory grown diamonds are 100% diamonds, and just like mined diamonds our laboratory grown diamonds are evaluated according to the 4Cs of diamond grading. The 4Cs are color, clarity, cut and carat weight, and they are the globally accepted standards used to assess the quality of diamonds.

The higher the clarity grading, the less inclusions or blemishes a diamond has, making it a higher-value diamond than one with a lower grading.

Diamond clarity is a measure of the purity of the stone graded by the visibility of two types of characteristics - inclusions and blemishes. 
In order to assess clarity, the diamond is inspected under 10x power magnification. The number and nature of external (blemishes), and internal characteristics (inclusions), as well as their size and position, determine the grade. 
Gemologists grade diamonds from Internally Flawless (IF) as the highest quality to Included (I3).

No, nearly all diamonds (mined or laboratory grown) have inclusions. Metallic inclusions can occur in laboratory grown diamonds. If an expert spots a trace of metal in a diamond, they can assume it is laboratory grown. While laboratory grown diamonds with defects do exist, Swarovski only uses high quality laboratory grown diamonds certified by the International Gemological Institute (IGI) according to the 4Cs to ensure that only the finest quality diamonds join the Swarovski Created Diamond collections.

No, laboratory-grown diamonds do not get cloudy over time. They are 100% identical to diamonds with the same physical and chemical properties, and should not degrade or change appearance over time. Where poor quality diamond seeds have been used, some laboratory-grown diamonds contain obvious defects, such as color tinges from impurities in the diamond or crystal structure imperfections. The laboratory grown diamonds processed in Swarovski Created Diamonds jewelry are a very high quality standard and do not have unnatural, problematic characteristics.

Diamond facets refer to each flat surface that creates the shape of a diamond. Every diamond possesses multiple facets that enable it to absorb and reflect light.

We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but what diamond cut actually does mean is how well a diamond’s facets interact with light.  The cut of a diamond is the measure of the quality of the shape, geometry and finish of the diamond.  Round brilliant diamonds receive a formal cut grade on a scale from Ideal (the best) to Poor.  Swarovski is uncompromising on cut quality to ensure all of our laboratory grown diamonds have optimal light performance and sparkle.

Cut refers to how a diamond’s facets interact with light to reveal its internal fire. It is the cut that gives each diamond its personality, and perfecting laboratory grown diamonds proportions, symmetry, and precision-cut angles of Swarovski Created Diamonds gives them their brilliant shine. The best cut has a balance between the width and depth to create symmetry, neither to shallow nor to deep. Creating the perfect refraction point for light through the diamond, reflecting it within the diamond and highlighting its polished brightness.

Color refers to the natural tint inherent in white diamonds. The industry standard for grading color is to evaluate each diamond against a master set then assign a letter grade from D (colorless) to Z (light yellow). 
The closer the diamond is to being colorless, the higher its quality.

Where poor quality diamond seeds have been used, some laboratory-grown diamonds contain obvious defects, such as color tinges from impurities or structural imperfections. Swarovski does not sell laboratory grown diamonds with unnatural, problematic characteristics.

A carat is a unit of weight used specifically to measure precious stones including laboratory grown diamonds. A diamond may have a higher carat weight without appearing larger, and two diamonds of the same carat weight can vary in size if one is cut deeper than the other. One carat weighs 1/5 of a gram and is divided into 100 points.

Carat weight it the standard weight unit for diamonds, and the first step in the grading process. Diamond carat weight is the measurement of how much the diamond weighs. Each carat can be subdivided into 100 “points.”  This allows precise measurements to the hundredth decimal place. The weight of a diamond smaller than one carat may be described by its “points” alone. The larger the diamond is, the more carats it will be, but only you can decide how important that is to you.

This is an entirely personal question. If you are looking for a larger diamond, you should look for a higher carat, as this indicates the weight and therefore the size of the diamond.