Diamond Query: The Best 2.5-Carat Round Cut Diamond Based on Fluorescence, HCA Tool, and Symmetry


| Anonymous Reader


Hello Sebastian,

Great site and love your work! Really invaluable. I am deciding between these 2 diamonds.

Please refer to the details below:


2.55 CT E VS2 Excellent Round Cut Diamond SKU-18060679

2.55 CARAT E-VS2 EXCELLENT CUT ROUND DIAMOND

SHAPE: Round

CARAT WEIGHT: 2.51

COLOR: E

CLARITY: VS2

CUT: Excellent

POLISH: Excellent

SYMMETRY: Excellent

FLUORESCENCE: Medium

L/W/D (MM): 8.67*8.63*5.40

L/W RATIO: 1.00

DEPTH %: 62.40

GIRDLE: Medium – Slightly Thick

TABLE %: 57.00

CULET: None

CERTIFICATE: GIA

CROWN ∠: 35.50

CROWN %: 15.50

PAVILION ∠: 40.80

PAVILION %: 43.00


2.05 CT E VS2 Excellent Round Cut Diamond SKU-16664287

2.05 CARAT E-VS2 EXCELLENT CUT ROUND DIAMOND

SHAPE: Round

CARAT WEIGHT: 2.08

COLOR: E

CLARITY: VS2

CUT: Excellent

POLISH: Excellent

SYMMETRY: Excellent

FLUORESCENCE: None

L/W/D (MM): 8.39*8.33*4.94

L/W RATIO: 1.01

DEPTH %: 59.10

GIRDLE: Thin – Medium

TABLE %: 60.00

CULET: None

CERTIFICATE: GIA

CROWN ∠: 32.50

CROWN %: 12.50

PAVILION ∠: 41.20

PAVILION %: 43.50

On paper one is 0.5 carat larger, HCA’s are 2.7/2.4 (respectively) and they are roughly the same price. Why should I not go for the larger carat? Is the VS2 vs eye clean that different in these 2 diamonds? My thanks in advance!

Your Diamond Teacher |

Thank you for your inquiry. I am happy to help. You should purchase the 2.51ct. It does have medium fluorescence, which means it may glow blue under strong UV light, which isn’t a bad thing, unless you don’t like that!

There is also the very slight chance that the medium fluorescence can make the diamond appear hazy, but again, not likely. The crown and pavilion angles on this diamond are great. And these are critical angles for better light performance.

As for the clarity, they are both eye-clean, since they are VS2 and the inclusions do not have a negative impact on the diamond.

Please let me know any additional questions you may have.

| Anonymous Reader


Thank you, Sebastian. Your time and valued opinion is very much appreciated. I have learned a lot from your website and am grateful for the time you have taken to carefully review and response to my query. Many thanks!

Your Diamond Teacher |

My pleasure! Let me know what you think of the diamond when you receive it!

I’d love to hear back!

| Anonymous Reader


Hi Sebastian, I trust you are well and am I hopping you can provide me some additional guidance before make a significant investment!

I’m holding 2 diamonds for 48 hours with James Allen. (A) below you have already seen. (B) is a new one that I would value your opinion on.

A.) 2.55ct, E colour, VS2, Excellent cut, HCA 2.7, $29,790:

2.55 CT E VS2 Excellent Round Cut Diamond SKU-18060679

B.) I am also holding this one: 2.5ct, D colour, SI1 (eye clean), excellent cut, HCA 0.9 $32,200:

2.50 CT D SI1 Excellent Round Cut Diamond SKU-16870970

Diamond (B) has GIA symmetry of “very good” instead of “excellent” but given HCA is 0.9, I was wondering if it is still a better value for money than (A) given it is ‘eye clean’.

Would value your opinion on (A) vs (B) and also on the relative merits of symmetry vs HCA. I note that Pricescope says the following about HCA:  “_Scores of 0-1 are usually NOT BEST FOR RINGS.

Most people prefer stones that score 1-2, or even top Hearts & Arrows symmetry stones up to 3.0_.” My sincere thanks in advance.

Your Diamond Teacher |

Nice to hear back from you. So, when purchasing a diamond online, shoppers will use as many tools as they have available to help them make an informed and educated decision, since they can’t see the diamond in person.

Most of these tools are not available in a brick and mortar retail store. People just count on what they see in person to decide on a diamond and perhaps have a diamond grading report to consider, as well. With this being said, tools like HCA, have a place if you are really stuck between two diamonds and you need someway to make a decision.

In reality, if I placed three diamonds in front of you with varying HCA scores, you would have a very hard time, it not impossible time telling the apart.

The two diamonds you selected are practically identical. The only thing that would really separate them is the medium fluorescence on diamond sku 18060679, since it will most likely glow a blue color under strong UV light.

The difference between Very Good and Excellent symmetry and polish will not be detected by the naked eye and is even a task to evaluate with a trained eye under 10x magnification.

At this point, I would choose based on your gut, based on price and whether fluorescence is a drawback or not for you. I hope this helps. Please let me know if I can give you more guidance.

| Anonymous Reader


Fantastic advice. Once again thank you Sebastian for your time. I really appreciate it.

I will let you know how it goes and what my gut is telling me!