Why does everyone dread the "bow tie" effect in fancies??

[shoemortgage1979]

Why does everyone dread the "bow-tie" effect on fancies such as marquise or pear diamonds??

I have read other places that a symmetrical bow-tie is to be looked for. I personally like the look of a marquise with the bow tie, as long as the diamond itself is of good clarity. I am a little confused

Can someone help me better understand this??

 

[AChiOAlumna]

Maybe one of the professionals can give a good explanation...I, for one, like the slight bow-tie effect in my original e-ring Marquise cut stone. I always knew it was mine and it gave the diamond some character...I''m sure there''s a reason NOT to have the bow-tie, but I don''t know what it is...

 

[valeria101]

Date: 4/15/2005 4:35:20 PM
Author: AChiOAlumna

I''m sure there''s a reason NOT to have the bow-tie, but I don''t know what it is...

As much as I know (= not much, really) there''s no way to get rid of the bow-tie completely and keep proportions in check (allot of extra depth might elimnate the visual effect - but "exta depth" hits 80% for this).

No idea where that "hate the bow-tie" mantra comes from

 

[icekid]

personally, i don''t want a big dead area in the middle of my stone. and it''s that simple.

 

[FireGoddess]

Same reason as icekid. Not a big fan of dead spots. I don't believe bowties can be eliminated completely, but finding a stone whose bowtie is minimized or not apparent as a big dead spot is a good thing, IMO.

Here's GOG's webpage on fancies, which I found interesting: link

Here are bowtie pics from the same GOG webpage I referenced above.

 

[NyssaLynne]

My marquise has a minimal bow-tie and is much more attractive than one I had in the past that had a more distinct bow-tie.

 

[Michael_E]

This thread is a very good example of the diversity that people have regarding what looks good to them. The "dead spots" in these stones that make up the bow tie effect can be large or small and are only really apparent when looking straight into the table of the stone. They can only be eliminated by making these stones very deep, as Valeria has suggested. This increased depth makes setting the stones more difficult and requires that they sit higher on your hand, (to avoid being poked by the culet). If you were to look at one of these stones through an Idea scope it would show a very white bow tie and a large amount of white elsewhere. So what ? If you like the look you are in luck, as the prices are lower for these . If you don''t like it, well just be prepared to pay the big bucks. You''ve got to admit that they are all beautiful. I can even see a design where a pair of side stones were cut to "leak" their color into the marquise or pear and make the bow tie look pink or blue. With a little imagination you can things that others scoff at into very unique, unusual pieces that can really turn heads.

 

[valeria101]

Date: 4/15/2005 6:44:19 PM
Author: Michael_E

If you were to look at one of these stones through an Idea scope it would show a very white bow tie and a large amount of white elsewhere.

One reason why I can''t say bow ties are bad... is that sometimes that''s the brightest part of the diamond anyway (deep red or black under the famous ''scope). And if it''s not all that big so that the facet pattern gets dissrupted, all for the better.

 

[cinnabar]

Date: 4/15/2005 6:44:19 PM
Author: Michael_E
They can only be eliminated by making these stones very deep, as Valeria has suggested.  

Is that really the only way?  I have never seen a bowtie in my pear, which is cut shallow rather than deep (58%).  It is also a rather fat pear at 1:1.37, so I assumed the combination of shallow+fat was what made it work.

 

[Michael_E]

cinnabar,
You''re right. That''s not the only way. Those that have the greatest length to width ratio, like pears and marquises, have the most tendency to show the bow tie since the angles from the farthest points are more shallow than the angles across the shortest width. If you design the cut to not show bow tie by giving it good angles across it''s width then the angles in the long direction will be shallow. With your stone being "fatter", the angles are closer to each other and it''s probably very nice looking because of it. The shallow ends are not really bad either, but they do tend to shoot light off in directions where your eyes often are not, making the pointy ends look darker. This all depends on where the lights are coming from though and any diamond can look fabulous in the right lighting. That''s why a well designed jewelry store will have lots of points of light all over the place. They may not be enough to draw attention to themselves, but they will really make a diamond sparkle !
Just for your info, the reason that those types of cuts work better when cut deeply is that you are basically merging a round brilliant pavillion to any shape that you want and it takes depth to do this. The drawback is that these stones have very steep facets next to the girdle and this can give poorer tilt brilliance, (not to mention that they are the devil to set !).

 

[Garry H (Cut Nut)]

Date: 4/15/2005 7:54:33 PM
Author: valeria101

Date: 4/15/2005 6:44:19 PM
Author: Michael_E

If you were to look at  one of these stones through an Idea scope it would show a very white bow tie and a large amount of white elsewhere.

One reason why I can''t say bow ties are bad... is that sometimes that''s the brightest part of the diamond anyway (deep red or black under the famous ''scope). And if it''s not all that big so that the facet pattern gets dissrupted, all for the better.

Correction - the bow tie is black in the ideal-scope.
It is head shadow most often - not leakage - that is a failing in the GIA course notes that led people to assume that.

 

[diamondlil]

I have noticed a significant difference in the bow-tie effect in different stones. I always wondered why that is the case. My pear has very minimal bow-tie but is also on the deeper side at 66 percent. I guess that''s a good thing because I personally don''t like to see that darker area so obviously when I look at pear shaped stones. It does not bother me as much in a marquise, I suppose, because the stone is symmetrcal. But in a pear I don''t want it to be noticeable.

 

[valeria101]

Date: 4/16/2005 2:29:22 AM
Author: Garry H (Cut Nut)

Correction - the bow tie is black in the ideal-scope.

I must be missing something. These are not quite black...

Isn't the bow-tie the steepest angle of the pavilion (relative to the vertical axis) ? That might make the area prone to become a reflector (show black under 'scope) or not... At least sometime that doesn't seem to be the case. And "sometimes" may mean allot of times given how many manquees err on being to shallow rather than too deep cut.

(the 'scope pictures below come from GOG and WF)

 

[cinnabar]

Date: 4/16/2005 2:18:21 AM
Author: Michael_E
This all depends on where the lights are coming from though and any diamond can look fabulous in the right lighting. That''s why a well designed jewelry store will have lots of points of light all over the place. They may not be enough to draw attention to themselves, but they will really make a diamond sparkle !

Ah, now that explains the Costco effect

  My local store has more/better halogens than Tiffany''s.

 

[Michael_E]

It is head shadow most often - not leakage - that is a failing in the GIA course notes that led people to assume that.

Right you are Garry ! It''s not just in the GIA course notes either. Many discussions around ray tracing suggest that light rays that enter and exit perpendicular to the table will give maximum brightness, when in reality they give maximum head reflection. So, unless you''ve got a light bulb on your forehead, you can end up with a darker stone because you are in essence looking at yourself. This brings up a question in regards to the Ideal Scope and it''s prediction of the look of a diamond which shows significant black reflection areas. If those black reflection areas are head shadow and it is dark, then won''t that make the diamond look darker ? Or does the distance from the diamond play a significant role in the look of areas that show black under the Ideal Scope ?