The Diamond 4Cs and DAII™ Grades: How to Compare Diamonds
You are choosing between two diamonds: one is D colour with VS2 clarity; the other is G colour with IF clarity. One has the higher colour grade, the other the higher clarity grade. Which should you choose?
This is where many buyers get stuck, even after learning about the 4Cs. Carat, colour, clarity and cut describe a diamond’s weight, colour, inclusions and surface characteristics, and cutting quality. They explain each specification separately. But how do you compare the overall quality of different combinations?
RAGAZZA’s DAII™ Diamond Quality Index was developed to answer that buying question. Designed for round brilliant diamonds, it assesses 16 factors, including colour, clarity, cut, proportions, symmetry, fluorescence and grading report information, to express overall quality as a single score. A higher score indicates a stronger overall assessment, giving you a consistent way to compare different 4C combinations in natural diamonds and lab-grown diamonds.
Start with the 4Cs, then use DAII™ to distinguish diamonds that excel in just one specification from those that deserve priority for their overall quality. Our DAII™ Diamond Quality Index page introduces the system. Here, we will use the grade comparison and real diamonds to show how it helps you choose.
Contents
(1) What the four DAII™ grades mean
DAII™ groups round diamonds into four grades: Basic, Standard, Premium and Collector. The table below brings together their scores, typical 4C specifications and quality levels, so you can see what to look for at each grade.
DAII™ grades, 4C specifications and quality levels
DAII™ grade and score | Typical 4C specifications | Quality level |
Basic DAII™ below 5.00 | Colour: mainly around F Clarity: mainly VS Cut: usually Very Good or above | Basic overall quality, with room to improve in colour, clarity, cut or proportions. |
Standard DAII™ 5.00–6.99 | Colour: mainly around E Clarity: mainly VS to VVS Cut: usually Very Good or above | An entry-level quality standard and a starting point for comparing diamonds within your budget. |
Premium DAII™ 7.00–8.99 | Colour: mainly around D Clarity: mainly VVS Cut: mainly Excellent | A strong balance across multiple qualities. A key range we compare when selecting high-quality round diamonds. |
Collector DAII™ 9.00 or above | Colour: D Clarity: Flawless to VVS, mainly Flawless to IF Cut: Excellent or above | Exceptionally rare round diamonds with outstanding assessments across multiple factors. The highest grade in our diamond selection standard. |
The colour, clarity and cut descriptions are a guide to the specifications commonly found in each grade. Proportions, angles, symmetry and other quality factors also affect the DAII™ score, so different specification combinations can fall within the same grade.
Carat measures weight and does not determine the DAII™ grade. A larger diamond does not automatically move up a grade. Choose a size that suits your budget and how you want to wear it, then compare overall quality.
Each grade can include different 4C combinations. For example, both a VS2 diamond and a VVS1 diamond can fall within the Premium range of DAII™ 7.00–8.99, with strengths in different areas. Later in this article, we compare two diamonds with different clarity grades that both score DAII™ 7.44.
Collector grade sets a much higher standard. Reaching DAII™ 9.00 requires outstanding quality across multiple factors at once. A few impressive grades on a report are not enough on their own.
(2) Carat: choose your size, then compare quality
Carat is a measure of a diamond’s weight. When shopping, first choose a carat range that suits your budget and the look you want. Comparing quality within that range makes it easier to find a diamond that fits your needs.
DAII™ does not award extra points simply because a diamond is heavier. A 1.00 ct diamond and a 2.00 ct diamond can have the same DAII™ score. Their size and price differ, while their overall quality can be in the same grade.
If you want a diamond to look larger face-up, check its measurements in millimetres too. Diamonds of the same carat weight can have different face-up sizes because of their proportions. Our guide to diamond table and depth percentages explains this in more detail.
(3) Colour versus clarity: use DAII™ to compare the whole diamond
Colour and clarity answer different questions. D is the highest colourless grade; IF means Internally Flawless. Both matter, but buyers often need to decide which combination makes the most sense within their budget.
With D / VS2 versus G / IF, the first diamond has the colour advantage and the second has the clarity advantage. Looking at specifications separately gives you a reason to favour either one. DAII™ assesses them alongside cut and proportions, helping you see which diamond has the stronger overall quality.
A Premium diamond does not have to be VVS, and IF clarity does not automatically make a diamond Collector grade. Aim for specifications that meet your preferences, together with strong overall quality. For more on colour differences when shopping, see our diamond colour grading guide.
(4) Same cut grade, different overall performance
Many buyers start by choosing Excellent or Ideal cut, then compare colour and clarity. That is a useful starting point. When narrowing the selection further, proportions and angles often help distinguish stronger diamonds.
Even when two diamonds receive the same cut grade from the same grading laboratory, their table percentage, total depth, crown angle and pavilion angle can differ. These details affect how light travels through the diamond and contribute to brightness, fire and its overall appearance.
DAII™ includes these proportion measurements in its overall assessment. You can move beyond “the cut grades are the same, so they must be similar” and use the score to identify candidates with stronger overall quality.
If optical symmetry also matters to you, read our complete guide to hearts and arrows diamonds and consider proportions, symmetry and the diamond’s actual appearance together.
(5) Real examples: VVS1 and VS2, both scoring DAII™ 7.44
Consider these two lab-grown round diamonds. Both have D colour, IGI grading reports, Ideal cut, Excellent polish and symmetry, and None fluorescence. Their weights are also very close.
Specification | Diamond A | Diamond B |
IGI report number | 836603997 | 762541051 |
Carat | 1.02 ct | 1.04 ct |
Colour | D | D |
Clarity | VVS1 | VS2 |
Cut | Ideal | Ideal |
Table percentage | 59% | 57% |
Total depth percentage | 61.4% | 61.4% |
DAII™ score | 7.44 | 7.44 |
DAII™ grade | Premium | Premium |
Diamond A has higher clarity. Diamond B has an advantage in the assessment of table proportions and other factors, balancing the difference in clarity. Both reach DAII™ 7.44.
Different clarity grades do not necessarily mean a large difference in overall quality. One diamond’s strength is its clarity; the other achieves a balance through its proportions and other qualities. Both are Premium grade.
If the clarity grade is a priority for you, consider Diamond A first. If VS2 meets your requirements, Diamond B is another Premium option with the same overall quality score. DAII™ helps you understand the strengths you are choosing between, rather than dismissing VS2 solely because VVS1 is a higher clarity grade.
(6) Real examples: our choice between D / VS2 and G / IF
Here is another comparison that leads directly to a buying decision. Both diamonds are IGI-graded lab-grown round brilliants, with Ideal cut, Excellent polish and symmetry, and None fluorescence. Their weights differ by just 0.01 ct, and their face-up diameters are very similar.
Specification | D colour / VS2 | G colour / IF |
IGI report number | 739597756 | 656491314 |
Carat | 1.22 ct | 1.21 ct |
Colour | D | G |
Clarity | VS2 | IF |
Cut | Ideal | Ideal |
Face-up diameter | 6.89–6.91 mm | 6.90–6.92 mm |
Table percentage | 57% | 60% |
Total depth percentage | 60.5% | 59.8% |
DAII™ score | 7.07 | 4.63 |
DAII™ grade | Premium | Basic |
Price in this comparison | HK$3,305 | HK$3,927 |
In this comparison, we recommend the D / VS2 diamond.
The D / VS2 diamond has the higher colour grade and the stronger overall assessment at DAII™ 7.07. The two diamonds are similar in size, and the D / VS2 is also less expensive. IF clarity is an advantage for the G / IF diamond, but considering these two diamonds’ overall quality and prices, D / VS2 is the better buy. Even at the same price, we would still give priority to the D / VS2 diamond with the higher DAII™ score.
This is the practical value of DAII™: when faced with different 4C combinations, you get a clear comparison to help decide where to spend your budget. For more examples of how to compare diamonds, read our guide to choosing diamonds with DAII™.
(7) Why DAII™ 9.00 Collector grade is so rare
D colour, Flawless (FL) clarity and 3EX are many buyers’ idea of top specifications. 3EX means Excellent cut, polish and symmetry. To reach Collector grade at DAII™ 9.00, however, proportions and the other quality factors must also perform exceptionally well.
Our actual diamond selection results show how rare Collector grade is. In a recent inventory review covering 130,816 diamonds, only 1 lab-grown round diamond reached DAII™ 9.00 or above. Just 8 natural round diamonds reached the same grade.
Diamond origin | Number scoring DAII™ 9.00 or above |
Lab-grown round diamonds | 1 diamond |
Natural round diamonds | 8 diamonds |
The sole Collector-grade lab-grown round diamond has GIA report number 6491872494. It weighs 1.51 ct, with D colour, IF clarity, 3EX and None fluorescence, and scores DAII™ 9.02. Although its clarity is IF rather than FL, its outstanding overall quality earns it Collector grade.
Collector grade identifies exceptionally rare diamonds whose qualities work together at an outstanding level. High specifications provide the foundation; their combined performance is what matters.
Premium diamonds scoring DAII™ 7.00–8.99 already deserve serious consideration. Collector diamonds at DAII™ 9.00 or above represent the higher level of quality we search for among large numbers of candidates. Read about the design principles behind DAII™ to understand our approach to diamond selection.
(8) How to use the 4Cs and DAII™ together
Start with your budget and carat range, then set the colour and clarity requirements you want to keep. Your shortlist will suit how you intend to wear the diamond and make comparisons under similar conditions easier.
Next, compare DAII™ scores. When scores differ, give priority to diamonds with stronger overall quality. When scores are equal, consider whether you value higher clarity, stronger proportions or a price advantage most.
DAII™ brings multiple quality factors together under a consistent assessment framework, making diamond selection more systematic. We then use diamond videos and physical inspection to check transparency, colour tints and actual appearance, connecting the data to the diamond you will wear. Our round diamond selection and inspection process and essential guide to buying diamonds online explain these practical checks.
Bring us your shortlisted diamonds and budget, and book a diamond consultation. We can compare specifications, DAII™ grades and the actual diamonds with you to find the option that offers more for your money.
(9) Frequently asked questions
Q: What is DAII™?
A: DAII™ is RAGAZZA’s Diamond Quality Index for round brilliant diamonds. It combines 16 quality factors into a score to help you compare the overall quality of different 4C combinations.
Q: Does a DAII™ score of 7.00 or above require VVS clarity?
A: No. The D-colour, VS2 lab-grown diamond in this article scores DAII™ 7.44 and is Premium grade. Strengths in proportions and other quality factors can help a diamond with a lower clarity grade achieve an excellent overall score.
Q: How should I choose between two diamonds that both score DAII™ 7.44?
A: Decide which strengths matter most to you. In our VVS1 and VS2 example, the first diamond has higher clarity, while the second achieves a balance through proportions and other factors. Compare their prices and actual appearance to find the better fit for your preferences.
Q: Does DAII™ 9.00 require D colour, FL clarity and 3EX?
A: Collector grade reflects outstanding overall quality rather than one fixed set of 4C grades. The sole Collector-grade lab-grown diamond in this review has D colour, IF clarity and 3EX, and scores DAII™ 9.02. Proportions and other quality factors also determine whether a diamond reaches Collector grade.
Q: Does a larger diamond have a higher DAII™ score?
A: A higher carat weight does not automatically increase the score. Choose your carat range first, then use DAII™ to compare quality, balancing the size you want with overall performance.
Q: Can I use DAII™ when choosing a natural diamond?
A: Yes. DAII™ applies to both natural and lab-grown round brilliant diamonds, giving you a consistent quality measure to understand their specification combinations and overall performance.
The real examples and inventory figures in this article were checked on 8 October 2026. Diamond availability and prices are subject to current inventory and quotations.
