When discussing the 4Cs of diamonds, whether they are natural or lab-grown, they adhere to the international diamond 4C standard. Regardless of the certifying institution, the certificate must include the 4C grading.
Therefore, it is essential to understand the diamond 4C charts and how each criteria impacts the appearance and price of a diamond. Read on to find comprehensive charts on diamond quality standards:
The 4C standard originated from GIA, with the institute evaluating a diamond based on four dimensions: color, clarity, cut, and carat weight. They respectively represent the levels of diamond quality for:
- Color: Evaluating the color grade of a diamond from colorless to yellow.
- Clarity: Assessing the presence of internal and external flaws in a diamond.
- Cut: Examining the quality of a diamond's cut, including proportions, symmetry, and polish.
- Carat Weight: Measuring the size of a diamond in carats.
* Please note that the word "carats" is used to describe the weight of a diamond.1ct=0.2g
1. Diamond Color Grade：
Diamond color rating ranges from D to Z. The Diamond Color Scale is used to evaluate the absence of color in a diamond, with D representing colorless and Z indicating a diamond with a noticeable yellow or brownish hue. Here is a breakdown of the color grading standards:
· D, E, F: These grades represent colorless diamonds. They are the highest color grades and are highly valued for their pure white appearance.
· G, H, I, J: These grades are considered near colorless. They may have a slight hint of color, but it is usually only detectable when compared to higher color grade diamonds.
The diamonds sold by Zaiyou are all above a color grade of J.
· K, L, M: These grades are considered faint yellows. The diamond may start to show a yellowish tint, but it can still be an attractive choice, especially when set in yellow gold.
· N to Z: These grades represent diamonds with increasing levels of yellow or brown color. They are categorized as light yellow, fancy light yellow, fancy yellow, fancy intense yellow, fancy deep yellow, and fancy vivid yellow.
2. Diamond Clarity Grade：
Diamond clarity grading is based on a scale that assesses the presence of internal and external imperfections, known as inclusions and blemishes, respectively.
The clarity scale ranges from Flawless (FL) to Included (I3). The following diamond clarity chart can help understand the clarity grading standards:
· Flawless (FL) and Internally Flawless (IF): These grades represent diamonds with no internal or external flaws visible under 10x magnification. They are extremely rare and highly valued.
· Very, Very Slightly Included (VVS1 and VVS2): These grades indicate that very few, tiny inclusions are visible under 10x magnification. These inclusions are difficult to detect, even for experienced gemologists.
· Very Slightly Included (VS1 and VS2): These grades represent diamonds with minor inclusions that are visible under 10x magnification. However, they are still considered to have excellent clarity and offer good value.
· Slightly Included (SI1 and SI2): These grades indicate diamonds with noticeable inclusions under 10x magnification. The inclusions may or may not be visible to the naked eye, depending on their size, location, and clarity characteristics.
The clarity grade of the diamonds sold by Zaiyou is SI1 or above, with an average grade of VS.
· Included (I1, I2, and I3): These grades represent diamonds with obvious inclusions that may affect transparency and brilliance. Inclusions at this grade may be visible to the naked eye and can impact the overall appearance and value of the diamond.
3. Diamond Cut Grade：
The cut of a diamond greatly affects its appearance, symmetry, and fire, thereby directly influencing the quality of the diamond.
It is worth noting that different grading institutions have different names for cut grades, such as IGI and GIA. Please refer to the diamond cut classification chart below:
IGI Diamond Cut Grading SystemIGI grades diamond cut based on the following categories
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GIA Diamond Cut Grading SystemGIA grades round diamonds using the following categories
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Ideal： Diamonds with ideal proportions and symmetry, exhibiting optimal light reflection and brilliance. |
Excellent： Diamonds with excellent proportions, symmetry, and light performance, offering maximum brilliance and sparkle. |
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Excellent： Stones with excellent proportions and symmetry, resulting in excellent light reflection and brilliance. |
Very Good： Stones that exhibit a high level of brilliance and sparkle, with slightly less precision in proportions and symmetry compared to the Excellent grade. |
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Very Good： Diamonds with very good proportions and symmetry, offering excellent light reflection and brilliance. |
Good： Diamonds with acceptable proportions and symmetry, displaying good light performance and brilliance. |
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Good： Diamonds with good proportions and symmetry, displaying above-average light reflection and brilliance. |
Fair： Stones that show noticeable deviations in proportions, symmetry, and light performance, exhibiting slightly reduced sparkle and brilliance. |
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Fair： Diamonds with fair proportions and symmetry, showcasing moderate levels of light reflection and brilliance. |
Poor： Diamonds with significant deviations in proportions, symmetry, and light performance, resulting in diminished sparkle and brilliance. |
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Poor： Stones with poor proportions and symmetry, resulting in diminished light reflection and brilliance. |
While both IGI and GIA use a similar diamond grading scale, there may be some variation in the criteria and standards used for determining the cut grades. It's important to note that GIA is considered the more widely recognized and reputable grading authority globally. Please note that GIA does not have a specific category for "Poor" cut grade for round diamonds.
At Zaiyou Jewelry, we particularly love using lab grown fancy diamond shapes in our designs because they have unique characteristics that can be beautifully incorporated into our designs. However, it is important to note that there is no standardized cut grading for fancy-shaped diamonds. For example, a pear-shaped diamond can have a broader or narrower shape without affecting its grading. When it comes to grading, the main factors considered are symmetry, proportions, and light transmission. The grading criteria for fancy-shaped diamonds are divided according to the following standards:
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Ideal(IGI) Excellent(GIA) |
Diamonds with exceptional symmetry, proportions, and light transmission. They exhibit outstanding brilliance and sparkle. |
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Excellent(IGI) Very Good(GIA) |
Diamonds with good symmetry, proportions, and light transmission. They possess excellent brilliance and sparkle. |
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Very Good(IGI) |
Diamonds with significant deviations in symmetry, proportions, or light performance. They may lack the desired brilliance and sparkle. |
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Good(IGI) |
Diamonds with noticeable deviations in symmetry, proportions, or light transmission. They may have reduced brilliance compared to higher grades. |
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Fair(IGI) |
Diamonds with noticeable deviations in symmetry, proportions, or light transmission. They may have reduced brilliance compared to higher grades. |
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Poor(IGI) |
Diamonds with significant deviations in symmetry, proportions, or light performance. They may lack the desired brilliance and sparkle. |
Diamonds with significant deviations in symmetry, proportions, or light performance. They may lack the desired brilliance and sparkle.
It's important to work with a knowledgeable jeweler or rely on reputable grading reports from recognized institutions to assess the quality and characteristics of fancy-shaped diamonds accurately.
4. Carat weight：
Many people wonder why the carat weight of a diamond affects its grading. In reality, carat weight has a significant impact on the price of a diamond. For example, in the pricing system of diamonds, there can be a substantial price difference between a diamond weighing 0.99 carats and one weighing 1.01 carats, even though the actual difference in weight is only 0.02 carats.
While larger diamonds generally have higher carat weights and perceived value, the overall grade also considers the quality of the other factors. While the actual size of diamonds (carats) alone doesn't determine their value, it's about finding a balance between carat weight and the quality of cut, color, and clarity.
Consultation with a reputable jeweler or grading reports from institutions like GIA or IGI can provide accurate information about a diamond's grade based on carat weight. Lastly, it is also important to remember that in the case of lab-grown diamonds, they share the exact same physical, chemical, and visual properties of natural diamonds, and thus the quality of lab-created diamonds can be the same as in the 4C scales that we saw above.
