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Asking about HCA theory

Newgirl87

Rough_Rock
Joined
Jul 22, 2021
Messages
26
Hi Gurus!!

As I'm reading more on diamond cut, more question has come to my mind.
I do possess 2 diamond that in my eyes were:
1. GIA 0,4ct F VS2, HCA score 0,9
This diamond is white all the time, but not as sparkly and sometimes can be flat. When it's dirty the edges loose it's sparkle which I found very weird.
2. GIA 0,6ct F VVS2, HCA score 3,8
This diamond is very lively and the fire oh wow. But somehow can look bit yellowish on some lightning (home/office lightning mostly).
I rarely clean this one as it always sparkles. And I do wonder if the yellowish tint I see is because of the halo (melee was F, but looked very2 white)

Butttt,
3. I also have a heart cut GIA 0,9ct D VS2, set on WG solitaire
that are very very sparkly with crisp facet, but also easily looks yellowish. Which is impossible right? since it's a D!

I also read somewhere that well cut diamond is like a chameleon as they are reflecting colors around. Good cut stone will throw more colors than the bad one.
My question is:
- Is it possible for the second diamond outperforming the first one as it score very bad on HCA tools?
- Is well cut diamond change color more easily than the bad one?
- What is the best cert range if I want diamond that look white most of the time and still sparkles?

Btw I'm in Asia where we has no knowledge on ASET, so I'm relying on HCA tools and my untrained eyes =D

Thank you!!!
 
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Hi Gurus!!

As I'm reading more on diamond cut, more question has come to my mind.
I do possess 2 diamond that in my eyes were:
1. GIA 0,4ct F VS2, HCA score 0,9
This diamond is white all the time, but not as sparkly and sometimes can be flat. When it's dirty the edges loose it's sparkle which I found very weird.
2. GIA 0,6ct F VVS2, HCA score 3,8
This diamond is very lively and the fire oh wow. But somehow can look bit yellowish on some lightning (home/office lightning mostly).
I rarely clean this one as it always sparkles. And I do wonder if the yellowish tint I see is because of the halo (melee was F, but looked very2 white)

Butttt,
3. I also have a heart cut GIA 0,9ct D VS2, set on WG solitaire
that are very very sparkly with crisp facet, but also easily looks yellowish. Which is impossible right? since it's a D!

I also read somewhere that well cut diamond is like a chameleon as they are reflecting colors around. Good cut stone will throw more colors than the bad one.
My question is:
- Is it possible for the second diamond outperforming the first one as it score very bad on HCA tools?
- Is well cut diamond change color more easily than the bad one?
- What is the best cert range if I want diamond that look white most of the time and still sparkles?

Btw I'm in Asia where we has no knowledge on ASET, so I'm relying on HCA tools and my untrained eyes =D

Thank you!!!

Can you post the GIA grading reports? Ideally, you would reject diamonds that scored over 2 on the HCA and look further at those that score 2 and under. HCA is more of a rejection tool rather than a selection tool.
 
Can you post the GIA grading reports? Ideally, you would reject diamonds that scored over 2 on the HCA and look further at those that score 2 and under. HCA is more of a rejection tool rather than a selection tool.

Tbh I forgot where I put the GIA report =p

Yes I heard, that's why I'm asking if there's a possibility that low score HCA diamond still perform brilliantly.
 
I like your question. I have an O-P diamond ~.70 that got a dismal HCA score but I think it sparkles beautifully.
 
Tbh I forgot where I put the GIA report =p

Yes I heard, that's why I'm asking if there's a possibility that low score HCA diamond still perform brilliantly.

How do you know what the HCA score is if you don't have the certs with the measurements?

And if you have the stones in your possession, isn't the question moot? I mean, you are literally looking at them, so you can answer this?

A diamond can score poorly on the HCA but be cut so precisely that it's everything you would look for in a stone. Those are hard to find, but they exist. There are specific measurements/ ratios (hence the request for the GIA report) that are known to be in this great performing but not a great HCA area.

But again, if - to you - the diamond that scores poorly on the HCA is super amazing.... I think that answers your question? Or what am I missing?
 
How do you know what the HCA score is if you don't have the certs with the measurements?

And if you have the stones in your possession, isn't the question moot? I mean, you are literally looking at them, so you can answer this?

A diamond can score poorly on the HCA but be cut so precisely that it's everything you would look for in a stone. Those are hard to find, but they exist. There are specific measurements/ ratios (hence the request for the GIA report) that are known to be in this great performing but not a great HCA area.

But again, if - to you - the diamond that scores poorly on the HCA is super amazing.... I think that answers your question? Or what am I missing?

I have the first diamond for 10 years and test the HCA score back then. The second one is only months old but the cert is in the safe.

Please mind that I'm in Asia where diamond IS diamond, we don't talk about cut. So this is a question from someone with very untrained eyes, so most likely I cannot differentiate good cut vs ideal cut diamond? Just looking for more info on HCA score and what is ideal cut?
Is the behavior of reflecting light is relate with how good a diamond is cut? What about the yellowish I see on my F and D diamond that IMO is better cut ones?
 
I have the first diamond for 10 years and test the HCA score back then. The second one is only months old but the cert is in the safe.

Please mind that I'm in Asia where diamond IS diamond, we don't talk about cut. So this is a question from someone with very untrained eyes, so most likely I cannot differentiate good cut vs ideal cut diamond? Just looking for more info on HCA score and what is ideal cut?
Is the behavior of reflecting light is relate with how good a diamond is cut? What about the yellowish I see on my F and D diamond that IMO is better cut ones?

Color that you see in diamonds often depends on the environment it is reflecting. If you are indoors, with beige walls and yellow lighting, the diamonds reflect that color. The D and F appearing yellow should have nothing to do with their cut. They may not be bright and lively due to their cut, but the color should not be yellow. Take the diamonds outdoors - not in the direct sun - but in daylight. You should be able to get a better idea of their color.

Why did you buy the second diamond? I assume you liked what you saw in it? If so, why question it now? If you love the diamond, just enjoy it - particularly if it is too late for return.
 
Diamonds reflect what is around them and different combinations draw light from different locations.
That is why 2 diamonds same color, different proportions can return different colors from the environment to the eye when in the exact same location.
 
@MissGotRocks yes I do love the second diamond. I'm just newbie at learning about cut and wondering if my eyes can be trusted since it's not aligning with the HCA theory. Or, is it better for me to stick to the cert and HCA score.

@Karl_K I was observing both diamond side by side in my bedroom, which has warm white light and white walls. IMO the better cut F VVS2 looks yellower (while sparkler) than the F VS2 diamond which look very white (but kinda flat). So is this relate to the cut? Is better the cut the more 'surrounding' colour it will show?

Here's a photo of a second diamond (F VVS2) on warm white light and white walls. The center looks yellower to me rather than the halo (IRL it's more buttery yellow rather than gray in the photo). While the first diamond (F VS2) looks more white like the halo.
Can you also determine a good cut vs bad cut from pic like this?

1738719858236.png

Thanks you so so much!
 
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Adding more photo
1738724154194.png

Under table:
1738724233354.png
 
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