Cut of colored diamonds - educate me

[thecat]

I was on a colored diamond site and fell in love with 2 pink rounds but their prices are way too steep. So I am not looking at getting them. My question is if someone were to buy a round pink diamond, should she expect ideal cut proportions or at least near ideal proportions for the round? Or are colored diamonds a different kettle of fish altogether that we ignore the cut? But if we ignore the cut and accept leakage, would it just be a colored stone with no sparkle? Then any pink stone, not necessarily diamond, will do right?

 

[SirGuy]

There are a lot of experienced CS (colored stone) folks here, so I'm sure one of them will chime in too. But generally, the first thing to address is whether the color is natural or artificial. That is, plenty of colored diamonds are made that way with chemical or heating processes. Unscrupulous vendors will insist the diamond is natural, because it often is; it's just the color that isn't.

With stones like that, they're usually not cut as well. A poorly cut and tinted diamond can be turned into a novelty, artificially-colored diamond very easily. A natural colored diamond, in the fancy range beyond GIA's "Z," is a different animal.

Light return is light return. You're right that a poorly cut, fancy colored diamond won't look as good as a well cut fancy colored diamond.

Remember that with any diamond, cutting to ideal proportions wastes more rough. This is why an AGS 0 stone cut to .94 carats might be a better sparkler than a 1.01 carat GIA triple excellent. A lot depends on how much the cutter is willing to risk losing. Many buyers, even fairly educated ones, are drawn strongly by the allure of a heavier stone.

What's the most common first question when someone sees a diamond in a ring? You guessed it: "How many carats?"

This is even more critical with fancy colored stones, because the rough can be so much more expensive. There are also different light return properties to consider with fancy colored diamonds. With "clear" diamonds, a balance is struck between white light return and colored light return (brilliance and fire). With colored stones, one that is cut exactly the same might make a colored stone look less saturated than it is, because it could bounce back so much white light that it brightens the stone in a way the cutter doesn't want. So a lot of colored stones are fancy shapes to better capture the color of the original body tint.

Many CS folks recommend considering stones other than diamonds if color really appeals to you. A beautiful ruby could be preferable to a red diamond. "Ideal cut" is a phrase used a lot and quite casually. It's not a universal thing; for whom is it ideal, and why? The answer changes depending on the type and shape of stone. If "ideal" was a mathematically universal thing, with all gain for achieving it and no reason to avoid it, then every diamond would look like that.

Everything's a compromise.

Hope that helps!

 

[thecat]

Thanks for your sharing, Sirguy. You brought up an interesting point where if it's cut like the ideal round, the white light return will decrease the color intensity of the stone. It got me thinking if I had a piece of rough custom cut for me, would I prefer a more saturated color with good cut or less saturated with near ideal/ideal cut. I can't decide yet. But there's not a problem since I have no such rough.

 

[Karl_K]

Thanks for your sharing, Sirguy. You brought up an interesting point where if it's cut like the ideal round, the white light return will decrease the color intensity of the stone. It got me thinking if I had a piece of rough custom cut for me, would I prefer a more saturated color with good cut or less saturated with near ideal/ideal cut. I can't decide yet. But there's not a problem since I have no such rough.

First good job SirGuy.

Unless you owned the rough already given the economics of it you would not be given a choice if the cutter had to buy the rough.
They will go for what will sell the quickest for the best money.

 

[Gypsy]

We have a colored stone forum: [URL='https://www.pricescope.com/community/forums/colored-stones.11/']https://www.pricescope.com/community/forums/colored-stones.11/[/URL]

That's where the colored stone guru's are.

I will say this. CUT is NOT king with colored stones. Color is King. Faceting is important but not so much for light return, but to avoid issues like windowing. Also important are saturation, hue, and evenness of color...colored stones, even colored diamonds, are very different creatures than white diamonds. And if you are looking for a ring stone and NOT looking at diamonds then hardness and durability comes into play as well.

Precision faceted colored stones ARE gorgeous. And there are several cutters that the boards like to use. Jeff White is one. Gene at Precision gem is another.

But precision faceted colored DIAMONDs are rare. That said, I understand Infinity did a gorgeous suite of of custom cut yellow diamonds for one of our (very lucky) posters recently.

So if you have the funds, it is possible to commission a precision faceted colored diamond.

The reason you don't see them more often is because color is what counts with colored diamonds and so those diamonds are cut to maximize color, and also sometimes for weight retention, for financial reasons.

 

[Gypsy]

Pink sapphires would be an option. FYI. They will sparkle, but not like a diamond. They are a great choice for a ring stone as they are a 9 on the MOHs scale. And you NEED hardness for an engagement ring. I wouldn't go any softer than that.


Have you considered a three stone with small pink sidestones. Sapphire pears or (more expensive) light pink diamond pears?

That might be a good option to explore.

 

[thecat]

Thanks for your sharing, Sirguy. You brought up an interesting point where if it's cut like the ideal round, the white light return will decrease the color intensity of the stone. It got me thinking if I had a piece of rough custom cut for me, would I prefer a more saturated color with good cut or less saturated with near ideal/ideal cut. I can't decide yet. But there's not a problem since I have no such rough.

First good job SirGuy.

Unless you owned the rough already given the economics of it you would not be given a choice if the cutter had to buy the rough.
They will go for what will sell the quickest for the best money.

I don't know why it escapes me that I have no say in its cut

 

[thecat]

Pink sapphires would be an option. FYI. They will sparkle, but not like a diamond. They are a great choice for a ring stone as they are a 9 on the MOHs scale. And you NEED hardness for an engagement ring. I wouldn't go any softer than that.


Have you considered a three stone with small pink sidestones. Sapphire pears or (more expensive) light pink diamond pears?

That might be a good option to explore.

Thanks for your response, Gypsy. I will repost in the CS forum soon. I'm not looking at buying any pink gems. I was just browsing Leibish due to their up to 30% off cyber Monday. It was then I realised few colored diamonds are precision cut.

 

[SirGuy]

I was just browsing Leibish due to their up to 30% off cyber Monday. It was then I realised few colored diamonds are precision cut.

Colored diamonds can be cut as precisely as any other; it's just that the intent of the cutter may be different (regarding white light return, color entrapment, etc.)

 

[chrono]

I was just browsing Leibish due to their up to 30% off cyber Monday. It was then I realised few colored diamonds are precision cut.

Colored diamonds can be cut as precisely as any other; it's just that the intent of the cutter may be different (regarding white light return, color entrapment, etc.)

100% in agreement. They are precision cut but not for maximum white light return; they are cut to entrap as much colour as possible while still looking symmetrical, pleasing in form and brilliance.

 

[Karl_K]

I don't know why it escapes me that I have no say in its cut

You have to keep in mind that any rough showing the slightest pink tint is set aside and sold at super high prices based on predicted best color and size even in tiny sizes.
There is no room for the cutter but to go for the best color size combination.

 

[John P]

Gypsy, SirGuy and Chrono all hit the nail on the head. Unlike cutting for optimum face-up light return, FCDs are cut to entrap and exaggerate body color. This can be accomplished by bouncing color back into the center of the stone or allowing light to pass through and illuminate the color, so the geometries for FCDs are often outside those of diamonds in the D-Z range.

...Or are colored diamonds a different kettle of fish altogether that we ignore the cut?...

One very significant difference occurs at the lab, during color-grading: Remember that diamonds in the D-Z range are graded face-down, viewed through the pavilion, so the face-up color-impact of superior/inferior cutting, fluorescence, etc. is not accounted-for (don't get me started)... Meanwhile fancy-colored-diamonds are assessed for color face-up, with all relevant factors in-play. As you can imagine, this can be a game-changer for rough with even faint color.

They will go for what will sell the quickest for the best money.

Indeed they will. Diamond cutters are smart, and are increasingly assisted by planning technology which can help determine the best ways to entrap color and influence intensity in a given rough crystal. These decisions are very important, since diamonds judged to be in the lower D-Z range will sell for much more if cutting differently can make them become attractive FCDs instead.

When contemplating a color purchase, whether FCDs or gemstones, it is absolutely critical to actually see the gem. Our grading descriptors - while helpful - are really guidelines only. Each colored stone has its own personality.

 

[thecat]

Sirguy, Chrono, Karl, John, thanks for your insightful sharing. I appreciate it. I will come back with more questions should I find something affordable on sale. I can't believe that a 0.5ct pink diamond is so costly.

 

[Karl_K]

I can't believe that a 0.5ct pink diamond is so costly.

Here is part of the reason:
http://www.argylediamonds.com.au/argyle_pink_diamonds.html
By separating them and holding special tenders it raises the prices paid for each one which raises the cost to consumers. Many in the game have a stake in keeping prices high. If you can get the auction prices high it increases the value and selling price of what you already have. It is the same game that a few players play with fine large ruby.
Who knows how many they are sitting on also waiting for prices to go up.