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Carat weight loss setting

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
Hi, my first thread, close or merge if there’s a similar thread.

I read somewhere (not sure if accurate) that for diamonds, one should go for 1.01 or even 1.02 carat if aiming full 1carat diamond, due to possible loss of weight during the setting process, in order to retain at least 1.00 carat in final product. While I am not sure if that is even accurate, I wonder if there’s any perceivable carat weight loss when setting coloured gemstones, specifically corundum (ruby/sapphire) or emerald. Looks like there are significant price jumps at 1, 1.5 and 2carat marks and whether there is any reason to spend extra couple of hundred dollars to secure (for example) 1.01 or 1.02 carat rather than 1.00 to provide buffer after setting. Let the wisdom flow!
 

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
I guess scratches or chips to the surface? Heard setting is the time when diamonds are most vulnerable and thought the same for softer stones like corundum or emerald.
 

CSpan

Brilliant_Rock
Joined
Mar 7, 2016
Messages
957
I have never heard of this either. Could it be about face up size? Colored stones vary in weights and often face up larger or smaller than a diamond of comparable carat weight. I suppose diamonds can also face up larger but the setting wouldn't or I should say, shouldn't change the size. Plenty of folks buy .95 and .90 stones because they are close enough to the carat weight without tipping over the edge.

In colored stones I am all about the mms since carat often doesn't tell me much, especially with unique cuts. But that is just me.
 

Bron357

Ideal_Rock
Premium
Joined
Jan 22, 2014
Messages
5,170
Total nonsense. Any jeweller removing diamond carat weight while setting the diamond is damaging it and needs to go straight back to jeweller school!
What would be more accurate to say is that “estimating carat weight by dimensions” is not as accurate as weighing the diamond unset.
often times diamonds are appraised while set so the diamond carat weight is estimated by using its cut type and width and depth measurements. Not as accurate as weighing unset.
When buying diamonds it is often more cost effective to buy slightly under the 1 carat, the 1.5 carat and the 2 carat (and so on) weights. Nevertheless if visual size is important you should pay attention also to type of cut and dimensions. Some cuts look “smaller” face up than others to the eye.
But no, you don’t need to buy a diamond certified at 1.02 carat just in case some weight is lost.
Diamonds also don’t shrink in hot water and sadly, even regular watering and fertilizer doesn’t make them grow any bigger.
 

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
Total nonsense. Any jeweller removing diamond carat weight while setting the diamond is damaging it and needs to go straight back to jeweller school!
What would be more accurate to say is that “estimating carat weight by dimensions” is not as accurate as weighing the diamond unset.
often times diamonds are appraised while set so the diamond carat weight is estimated by using its cut type and width and depth measurements. Not as accurate as weighing unset.
When buying diamonds it is often more cost effective to buy slightly under the 1 carat, the 1.5 carat and the 2 carat (and so on) weights. Nevertheless if visual size is important you should pay attention also to type of cut and dimensions. Some cuts look “smaller” face up than others to the eye.
But no, you don’t need to buy a diamond certified at 1.02 carat just in case some weight is lost.
Diamonds also don’t shrink in hot water and sadly, even regular watering and fertilizer doesn’t make them grow any bigger.

Glad to hear that. So no fear about 0.50 and 1.00 carat gemstones!!
 

qubitasaurus

Brilliant_Rock
Premium
Joined
Dec 18, 2014
Messages
1,352
Hahaha, I would most likely fire the jeweler who put a deep gouge in my daimond (which had no evident structural issues) while setting it. Should not be possible to lose even 0.01 of a carat during setting.

On a purely seperate issue I really dont trust those scales to the second significant decimal place. At the very least I wouldnt be letting a random lab or store weigh it and tell me the weight correct to within 0.002 grams. Sure maybe theyd be right... maybe they wouldnt.
 

foxinsox

Ideal_Rock
Premium
Joined
Jul 18, 2015
Messages
3,506
Glad to hear that. So no fear about 0.50 and 1.00 carat gemstones!!

Not in terms of losing gem material to the setting process but if you're buying a stone for its cut qualities, I would be leery of stones at the magic numbers like 1/2 or a full carat etc.
It's highly likely the cutter may have compromised on some aspects of the cut to retain weight.
For example if you have rough that will yield an ideal cut of 0.8ct or average cut of 1.0ct, most cutters will choose to cut the 1.0ct even though it's not as good in terms of light return because it's worth more money to them for sale.
So be cautious of those nice round numbers if you're buying a stone like a diamond where the cut quality matters for light return.
 

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
Not in terms of losing gem material to the setting process but if you're buying a stone for its cut qualities, I would be leery of stones at the magic numbers like 1/2 or a full carat etc.
It's highly likely the cutter may have compromised on some aspects of the cut to retain weight.
For example if you have rough that will yield an ideal cut of 0.8ct or average cut of 1.0ct, most cutters will choose to cut the 1.0ct even though it's not as good in terms of light return because it's worth more money to them for sale.
So be cautious of those nice round numbers if you're buying a stone like a diamond where the cut quality matters for light return.

Yeah agree should get proper grading certificate for any substantial purchase,
 

T L

Super_Ideal_Rock
Premium
Joined
Sep 20, 2008
Messages
23,757
If I were to buy a 1 ct diamond, I would look for one that is 0.99 ct. as it would likely be priced lower than a similar stone that was 1.01 ct. You could never see the difference in weight with your eye, but feel it in your wallet.

Same reason I would go for an SI and not a VS or better, or a G/H vs a DEF color.
 

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
Same reason I would go for an SI and not a VS or better, or a G/H vs a DEF color.

Not sure why but market in Australia seem to favour G or above in terms of colour, I guess VS rather than SI for near-certainty about eye-cleanliness especially when you are shopping online.
 

PrecisionGem

Brilliant_Rock
Trade
Joined
Jul 27, 2004
Messages
1,761
Not in terms of losing gem material to the setting process but if you're buying a stone for its cut qualities, I would be leery of stones at the magic numbers like 1/2 or a full carat etc.
It's highly likely the cutter may have compromised on some aspects of the cut to retain weight.
For example if you have rough that will yield an ideal cut of 0.8ct or average cut of 1.0ct, most cutters will choose to cut the 1.0ct even though it's not as good in terms of light return because it's worth more money to them for sale.
So be cautious of those nice round numbers if you're buying a stone like a diamond where the cut quality matters for light return.

Cutting a gemstone is always of matter of comprimise, but which one do you choose. Cut for weight, cut for color, cut for clarity, cut for shape etc. In colored stones you will see some custom cutters cut these weird shapes to get the max size stone, but I find these shapes hard to sell.

One thing you can’t really do when cutting a stone is know the weight of the stone while you are cutting it. So you can for example be cutting a stone and think, well it looks like it will be 0.95 ct so I’ll make the girdle extra thick to push it to 1.1 ct.
 

Diamond Girl 21

Brilliant_Rock
Premium
Joined
Jun 26, 2017
Messages
1,079
Not sure why but market in Australia seem to favour G or above in terms of colour, I guess VS rather than SI for near-certainty about eye-cleanliness especially when you are shopping online.

There's no right or wrong regarding color and clarity. It's very personal. Let your eyes guide the decision.
 

Sydneyphoenix

Rough_Rock
Joined
Apr 4, 2021
Messages
54
There's no right or wrong regarding color and clarity. It's very personal. Let your eyes guide the decision.

Of course there isn’t right or wrong answer. Just reporting on my gauge of trend here. I also read that in Korea anything below G (or perhaps it’s “G or lower”, don’t know how words exactly translate) is not considered gem quality for diamond, people can be so picky. At least there SI1 seem to be the vogue rather than VS.
 

Diamond Girl 21

Brilliant_Rock
Premium
Joined
Jun 26, 2017
Messages
1,079
Of course there isn’t right or wrong answer. Just reporting on my gauge of trend here. I also read that in Korea anything below G (or perhaps it’s “G or lower”, don’t know how words exactly translate) is not considered gem quality for diamond, people can be so picky. At least there SI1 seem to be the vogue rather than VS.

Sure, I just meant that all that matters is what pleases you personally. :)
 
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