Recutting vs. revaluing

[7188429]

Good day!

I would like to ask a question regarding recutting gemstones. As I've come to understand sellers are charging gemstones based on carat weight if comparing equal quality gems with different carat weights.

Let's say I got a 4 carat unheated "Royal Blue" sapphire with a bad cut which I would like to give a full recut, which would bring the sapphire down to 2 carats. Then would the value of the gem still be the same, fall, rise? The reason for asking is that I would like to recut some gems of mine but I would like to know if their value would decrease hand-in-hand with the carat weight or not. I wouldn't like to lose a lot of $$$$$, suddenly overpaying for a gem.

 

[Seaglow]

Usually a poorly cut stone (say lopsided or heavily windowed) can easily shoot up in price once recut. The price per carat on the final weight should be able to cover or should be better that the old weight as a poorly cut stone including the cutting cost. Recently, I've been studying rough selection and have stones for recut and usually, a precision cut can even result in only 40% yield from a local cut, depends on how shallow or how heavy the belly is. So what is done for precious material is not to precision cut it, but to improve the cut by closing a window or making the stone symmetrical.

 

[chrono]

It will most likely fall because when there is such an extreme carat weight loss, it is very likely to affect the colour negatively, losing a lot of tone and most likely some saturation. Then again, if the cut was so terrible to begin with, it might look more attractive in terms of sparkliness if it was dead to begin with. There are too many factors to just give a single answer.

 

[Seaglow]

Here are my recuts for precision cut by The C Axis for sapphires and a spinel. The final weight was around 45-60%. I could have gotten a better yield if I didn't ask for precision cut.

If not precision cut, you can close windows higher depending on stone's cut even around 15-20% loss. In many markets, you can easily sell for weight, that's why the stones were cut for weight in the first place, But picky markets are willing to pay a large premium for well cut stones. Sometimes, a recut brings out or eliminates a color from the stone as in the case of my gray spinel - it became an almost straight gray, was much lighter, and took out the blue component. I know a cutter who buys locally cut stones, recuts them, and sells them to the US.

So for sellers, it's a question of, which sells faster, a big stone or a beautiful stone? And the answer to that depends on the market. So example, the bigger stones may sell well in Asia but the designers may grab the calibrated and beautifully cut ones. So recuts are also done for calibration. A calibrated stone can fit in a premold which jewelers love and may pay a premium on stone price if they save on setting cost.



Here is also a sapphire recut from Jeff Davies (photo credits to Jeff Davies Gems Jewellery). Original weight was 10.24 carats down to 6.68 carats. The stone immediate sold after recut.

 

[7188429]

I really favour Asscher cuts, thanks for sharing!

The spinel you got recut, what a massive difference! Are you sure it's due to the recut only or do you think it may have been cobalt-doped (some weird stuff they do to lifeless spinel's in Asia)? It seems like you found a very good faceter, may I ask who recut it for you?

https://www.gia.edu/gia-news-research/cobalt-diffusion-natural-spinel-report

May I also ask about the terms calibrated gems / custom cut gems / precision cut gems / laser cut gems, are they all the same or do the technique differ in some way?

 

[Seaglow]

I really favour Asscher cuts, thanks for sharing!

The spinel you got recut, what a massive difference! Are you sure it's due to the recut only or do you think it may have been cobalt-doped (some weird stuff they do to lifeless spinel's in Sri Lanka)? It seems like you found a very good faceter, may I ask who recut it for you?

May I also ask about the terms calibrated gems / custom cut gems / precision cut gems / laser cut gems, are they all the same or do the technique differ in some way?

The stones were cut by Ian Kalway of The C Axis. The cutter is my friend so I'm sure he didn't add anything either. Lol. No the spinel I bought in Yangon, it's Burmese, not doped and untreated. The stone is smaller so it became lighter. Also when you cut at a certain axis, some stones react differently, either lose color or add a color. So cutting at a certain axis can make a big difference at times especially in color-change stones and stones with a particular hue like padparadschas. I have a tourmaline that in reality is a bi-colored pink and green until preforming, then a golden color showed by tapering an axis so the final result is parti-colored.

 

[Seaglow]

On calibration and the rest. So usually jewelers have a jewellery mold to produce many pieces. Saves a lot from custom making each time. Say a stone should be 8mm X 6mm, cutters can cut a stone plus or minus .10mm from that size, then it could fit an 8mm X 6mm jewelry mold. In some markets like Asia, say a custom made jewelry or handmade jewelry may be cheaper, so stones are not sold calibrated. But in the US or Europe where labor can be highly priced for custom jewelry, the stones requested are usually calibrated.

Here's a sample of spinels that are calibrated to fit an 8mm X 6mm jewellery setting.



For precision cut, you have to follow precise angles when cutting, each facet is calculated following a diagram. When you say custom cut, it's what the customer wants - say if you want to turn your round stone into Asscher, want a diamond or a step cut. Laser cutting is usually used for fantasy cuts and not hand done, cut by machine. For precious material where saving weight makes a difference, stones are still usually cut by hand. A non-precision cut stone can still be a nicely cut stone, with decent facets, but if you look at each facet closely, they most likely will not be symmetrical with other facets of the stone.

I'm not a cutter so maybe a cutter can chime in as they know better than me.

 

[7188429]

Thanks a bunch for sharing all this information, I find it very helpfull and easy to understand

 

[normanintheskywithsapphires]

I did a recut from this windowed pink sapphire:


to this:


Lost 20% weight, 1.8 to 1.5 (if I remember correctly)

and it ended here:


I had zero regrets and, though I can't proof it, I'm positive that the value of the stone has gone up.

 

[7188429]

The outcome is quite amazing! Did you custom cut it or precision cut it?

I agree with you in regard of value considering the slight carat difference and still weighing 1.5 carats. What do you think about value if considering a 1-2 carat loss in a 4 carat stone? I assume you're a cutter?

Maybe it's all about the final outcome as Seaglow pointed out with the recut from Jeff Davies (10.24 carats down to 6.68 carats), which I personally would have paid the same price for anyhow, especially after the recut....

 

[PrecisionGem]

It’s a myth that the saturation will be lost on a recut. Most often the stone looks more intense as now the light is refracting through the stone properly and with out the open window.

Unless you are starting with a very shallow stone, the recovery of a recut should be somewhere around 60% or more. Don’t buy very shallow stones with the intent of having them recut.

 

[normanintheskywithsapphires]

The outcome is quite amazing! Did you custom cut it or precision cut it?

I agree with you in regard of value considering the slight carat difference and still weighing 1.5 carats. What do you think about value if considering a 1-2 carat loss in a 4 carat stone? I assume you're a cutter?

Maybe it's all about the final outcome as Seaglow pointed out with the recut from Jeff Davies (10.24 carats down to 6.68 carats), which I personally would have paid the same price for anyhow, especially after the recut....

No, I am not a lapidary at all. I wish though, but my eyes are too old now to learn new tricks.
I first bought the stone, studied it at home and send it back to get the window 'cut-out' (free of charge). Hence, it was a 'precision re-cut' if I get the terminology right.
A loss of 50% seems a lot but I'm not qualified to say so. Perhaps if a gem is totally mis-shaped or flat, then yes. On some of the cheaper websites you can find gems that look as if they need a radical over-working with lots of loss. But mine was already nice (and costly) at the beginning, but after re-cut it became extra perfect. It was a difficult decision for a newbie so I started a thread to get peoples' input. In the end, I had the guts and went against the forums' opinion and decided for the re-cut.
That discussion is here:
https://www.pricescope.com/community/threads/window-re-cut-yes-or-no.228415/

 

[Seaglow]

Hence, it was a 'precision re-cut' if I get the terminology right.
/

Your stone I think didn't undergo a precision recut, which is if you follow a precise diagram, it will go for much less final weight IMHO.

Viewing the original photo of the stone, and the side photo of the ring in your other thread, it appears to have mixed cut, typical of local cuts to save weight, and the bottom is still mixed cut, after recut. The cutter simply closed the window with a usual recut, thus the 15-20% weight loss. A precision cut using mixed cut is more work and I heard quite difficult as you will have to have a lot of symmetrical facets, so many precision cuts are diamond/brilliant cut (which is beautiful and gives brilliance) or step cut, scissors, etc., IMHO.

 

[7188429]

No, I am not a lapidary at all. I wish though, but my eyes are too old now to learn new tricks.
I first bought the stone, studied it at home and send it back to get the window 'cut-out' (free of charge). Hence, it was a 'precision re-cut' if I get the terminology right.
A loss of 50% seems a lot but I'm not qualified to say so. Perhaps if a gem is totally mis-shaped or flat, then yes. On some of the cheaper websites you can find gems that look as if they need a radical over-working with lots of loss. But mine was already nice (and costly) at the beginning, but after re-cut it became extra perfect. It was a difficult decision for a newbie so I started a thread to get peoples' input. In the end, I had the guts and went against the forums' opinion and decided for the re-cut.
That discussion is here:
https://www.pricescope.com/community/threads/window-re-cut-yes-or-no.228415/

Thanks for sharing the link, it's an interesting read. In regard of what I've seen for your recut I think you made the right decision even if the saturation changed the tiniest bit.

I've had couple of "cheaper" gems re-cut in the past to learn from the experience and outcome. The gem I'm considering re-cut at this point annoys me due to its window. It's an emerald cut, cut too shallow at the last step of the facets on the pavillion, the degrees of the last step don't match with the R.I. of the gem.... I don't understand why they did this. If it were to preserve weight they did a bad job, I bet they could've done better in the faceting process to start with.

In your post I read someone mentioning "hide the window in a proper setting". How are that done?

 

[chrono]

Precision cutting has very high standards:
http://www.osirisgems.com/precision_cutting

1. Meet point accuracy: Each facet in a fold is consistent in size and shape per the pattern, not just a meet line.
2. Brilliance: mirror-polished for highest lustre and brilliance
3. Angles and light return: angles and full reflections

Most recuts are not precision cuts, just pavilion tweaks, hence a full precision recut usually has much greater carat weight and often, face up size loss.

 

[Seaglow]

Norman's recut is a successful one closing a window.

I was the one who pointed out that some windows, especially when small, can be 'closed' with a proper setting so sometimes, it may not be necessary to recut them.

Please check this thread for samples.

https://www.pricescope.com/community/threads/will-this-close-up-when-set.178498/

 

[7188429]

Precision cutting has very high standards:
http://www.osirisgems.com/precision_cutting

1. Meet point accuracy: Each facet in a fold is consistent in size and shape per the pattern, not just a meet line.
2. Brilliance: mirror-polished for highest lustre and brilliance
3. Angles and light return: angles and full reflections

Most recuts are not precision cuts, just pavilion tweaks, hence a full precision recut usually has much greater carat weight and often, face up size loss.

Great educational read, thanks! I actually visited their website yesterday but didn't see this post.

 

[7188429]

Norman's recut is a successful one closing a window.

I was the one who pointed out that some windows, especially when small, can be 'closed' with a proper setting so sometimes, it may not be necessary to recut them.

Please check this thread for samples.

https://www.pricescope.com/community/threads/will-this-close-up-when-set.178498/

Thanks! Look like a closed basket would work best for this, having a bit of a distance to the bottom of the basket when mounted.

 

[chrono]

I found the distance thing to be opposite; having the metal as close as possible to the pavilion helps reduce it. I've done so for several CS.

 

[7188429]

I found the distance thing to be opposite; having the metal as close as possible to the pavilion helps reduce it. I've done so for several CS.

Do you make settings or are you a mounter, if I may ask?

 

[chrono]

Do you make settings or are you a mounter, if I may ask?

Neither; just personal experience since I buy non-precision cut stones that needs some "help" sometimes.

 

[7188429]

Sorry, I misunderstod. I saw your thread "Paraiba dipped in Coloured Sugar Sprinkles"... Not something I would've ever thought of myself but gosh, it's AMAZING!

 

[Arcadian]

Color is king in color world but in certain stones, that carat weigh also counts. I don't buy to recut, I leave that for someone else. but if you recut, make sure you get someone extremely good at it. A full precision cut as mentioned will result in a smaller stone, but not necessarily a more valuable one.

Then you have to go through the whole business of getting a new report, etc... The other thing is, once a stone is recut, especially one thats already got a high level color designation, theres no guarantee it will keep it after a recut.

I love a well cut stone, and have plenty of them, but color is where it is for me.

 

[normanintheskywithsapphires]

Your stone I think didn't undergo a precision recut, which is if you follow a precise diagram, it will go for much less final weight IMHO.

V

OK. So, a 'precision-cut' or 'precision re-cut' would be the same, that is a complete new design?

 

[chrono]

It can be the same design or completely different design.

 

[PrecisionGem]

I ran a query in my database of stones I did complete recuts on, and the average yield was 63.82%
Normally I like to do complete recuts rather than just touching up. Touch up recover7 is much higher, around 90%.

As a reference, my normal yield from rough stones is 33.4%. Keep in mind, I have bought thousands of pieces of rough, so I know what to look for, and am pretty selective on shapes of rough, so I get a pretty good recovery. Normally 25% is a good number to use when estimating yield from rough.

 

[mastercutgems]

My opinion on re-cutting a gem ;

To me it is the optimization of bringing out the most the gem mineral has to offer as far as color and optical properties. There are times the "native" or typical step cut pavilions and brilliant crowns do more for some gem minerals and color saturation types than the western " precision" cuts do to optimize the properties of the mineral type.

I have cut them all; on modern precision machines and I also have a jamb peg mast to fit on my ultra-Tec machine as well just for the fun of it and to learn what cutters in foreign lands do when they cut a gem. I have cut minerals from Apatite to Zircon even some of the crazy ones like Sulfur, Rhodochroiste, Sphalerite, etc. which can make you crazy and stink like rotten eggs. They all have their own personalities.

As long as the symmetry is correct and is not distracting to the eye why waste the wonderful material of a mineral to do a complex cut that in many cases will not improve the optics of the gem unless you love looking at your gems under 15x ???

To each their own; that is up to the personality of the cutter; it makes it neither right nor wrong...

It was fun entering all the international and domestic competitions some 20 years ago but when you get past all that you love to learn how to save the precious material and not waste what cannot be put back on once you grind it away.

I have over 5000 cutting diagrams, some by famous cutters and some I designed myself; many I have cut and many I will never cut as they do not give the best optical return for the gem mineral type.

Re-cutting to me is a way to save the natural resources where the optics were not taken into consideration when cut the first time. I am not a wasteful person by nature and when I see a lovely mineral that has had the pavilion chopped off to save weight and not considering the properties of the mineral I want to save it to be re-purposed to be loved by another.

There is a very limited supply of fine minerals out there for faceting. It is the cutters responsibility to the mineral to do it as much justice as they can to make it lovely and to be enjoyed by the person wearing it.

That is my opinion on re-cutting and cutting gem minerals. I am sure many will disagree but that is the joys of being an individual.

Most Respectfully;

Dana Reynolds
ASG Certified
Supreme Master Gem Cutter
#96CGE42

 

[7188429]

Are there any thread on this forum with something like "how to pick rough for faceting"? Looking for educational information on this one, and before and after pics.

 

[motownmama]

I just happened upon this and it's really piqued my interest. I have a small sapphire that has a lovely color but a large window and I have a very large aqua that's emerald cut also with a window. It might be interesting to investigate recuttings.

 

[chrono]

There are just too many variables to consider when buying rough, not to mention, here are different things to look out for, depending on the material. There have been some threads if you do a search but they are not comprehensive. In general, there is far less risk if you let an experienced lapidary take care of this as the imagined cost savings end up not saving much at all, and in fact, could end up costing you more.