shape
carat
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Other than the 4C's; what other characteristics and measurements should I pay attention to?

Gadabout44

Shiny_Rock
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I've acquired numerous suggestions on my journey on choosing the perfect engagement diamond. I've quickly learned about the 4 C's and a few terms such as "eye clean" and "fire". I've also learned some tips such as anything over VS2 is not noticeable to the naked eye and that sometimes an SI1 can show more "fire" than a VS graded due to less carbon specks. These are all helpful tips that I must know! However, I know there are still much more to pay close attention to.

Are there other tips and measurements I should be paying close attention to? I would like to be educated and learn what the ideal numbers are for crown, depth, and pavillion measurements for a round 1.4Carat Diamond (and why).

Someone had mentioned to me that I should look at the Table numbers. One post suggested that 55-57 is ideal, and anything over that may be too flat. I was hoping someone can elaborate on this and explain this to me as if I was 5.

Another member mentioned that I should also be paying attention to the mm size of the diamond and not just the carats, however I did not receive a reason or explanation on why so.

And lastly, I just have a basic question. I read a random thread where a poster had mentioned that they should make sure that the "Diamond is not set too high", out of curiosity, what does this mean and why is it a concern?
 
The most important thing is CUT. The reason these things are important is because it determines how a ray of light bounces around in the stone and returns
out the top for you to see vs. heading out the side or bottom of the stone.

Look here for more info
https://www.pricescope.com/wiki/diamonds/diamond-cut

There are 4 numbers that we pay close attention to when looking for a well cut stone.
Depth 60 - 62.3%
Table 54-58%
Crown 34-35 degrees (sometimes up to 35.5)
Pavilion 40.6 - 41 degrees

34 crown pairs with 41 pavilion and 35 crown pairs with 40.6 pavilion

You can also use the HCA tool to help. Look for stones to score 2 or under. You can find it and read more about it at the link below.
https://www.pricescope.com/tools/hca

As far as mm size, when sticking to the numbers above you should fall within an expected size range. Its different when dealing with fancy cuts. Same
carats can result in vastly different size stone. Anyway, you dont need to worry about mm if you stay with the numbers listed above.

Height of diamond...most people on PS prefer their stones set at a normal or low height. High set stones just look odd to me and some people claim
they get hit more often because they are high.


From your post...
"and that sometimes an SI1 can show more "fire" than a VS graded due to less carbon specks"
Not sure what you meant by this but its not correct. "Fire" has to do with cut mainly. Output from the stone could be affected by lots of inclusions, clouds
or pinpoints but that would be in a lower graded stone (SI1/SI2) and not a higher graded stone(VS).

I think I answered all your questions!
 
As tyty noted, clarity and sparkle are, mostly, not related.

Clarity impacts the look of a stone. Whether or not you see the diamonds birthmarks. But that is separate and apart from sparkle.

Sparkle is a function of cut and the results from the facets of the diamond taking in light, bouncing it around and then sending it back out to you. How well a diamond's facets are aligned by the cutter to bounce and reflect that light is what we can light performance.

In VS2 and below clarities there are some types of inclusions, like twining wisps, that can impact performance by impeding some of the light performance. In VS2 this is rarer than in SI2 generally because of the type and quantity of inclusions that go into each grade. Carbon rarely is bad for performance actually. Though black salt and pepper aren't attractive to most, they don't have anything to do with sparkle.
 
Here is a visual on crown angles. The crown angle controls the angle of the "muffin top" on a diamond. How steeply it raises up from the girdle. Its easier to see the difference if you compare the 32 to 36 in my example. All else being equal, the 32 has a small "muffin top" and the 36 has a big puffy "muffin top".

With low crown angles (32 here), the diamond does not have much weight on the top, but when set, it will tend to look a bit flat when viewed from the side. Even with good angles, these tend to create less fire in the diamond. With higher crown angles (36 here), the diamond carriers a lot of weight in the top. These diamonds can have good fire, but rarely. You tend to see a lot of leakage as there get to be fewer and fewer pavilion angles that work as very low pavilion angles create other problems. At the lower side of the PS range (34-35, 35.5), you can see there is still enough crown to be visible and attractive in a setting, but these also tend to have a nice balance of white light and fire.

To perform well, crowns must have a complimentary pavilion angles. That is what control how steeply the diamond bottom leaves the girdle (i.e., the "bottom pointy bit"). But, outside certain combinations of CA and PA, the light starts to just bounce out of the bottom of the diamond so you don't see it. Most diamonds are cut to maximize weight. You will see these referred to as "Steep Deep", they have high crowns and high pavilion angles.

Crown Angles
upload_2018-1-25_21-1-53.png
The table size (that amount of the diamond's total width that is horizontal at the top of the diamond) needs to give enough room for the upper facets to disperse light, but since modern round only accept light from that table it can't be too small either. So, the general range is 54-58 for a table that can be ideal. All can obtain a good light return. But, I like the visual look of tables under 57 as they just look nicer and tend to be a bit more fire.

I'm not sure I can do much more simple without missing important details, but ask more questions if I've made a muddle of things.

Trade or other technical folks please feel free to jump in!
 

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I explained why you need to pay attention to the millimeters.
 
Not related to measurements but another factor to consider is fluorescence. Strong and very strong fluorescence may cause a diamond to look milky, so you need to pay attention to that. Generally, you are safe with up to Medium Blue fluorescence, and you may be able to get a better price compared to a diamond with None.
 
This is great for layman information!

Thank you!
 
Here's a visual for setting height. Assuming a simple solitiare.

HIGH - see how much air is below the tip of the diamond and the ring?
upload_2018-1-27_5-3-1.png

upload_2018-1-27_5-8-12.png

LOW - The culet of the diamond is as low as possible. Usually requires some metal between the tip and the finger.
upload_2018-1-27_5-6-54.png
upload_2018-1-27_5-4-38.png

I personally always look for the setting to be as low as possible. It help me knock the ring around at much.
 

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And what about band heights?

Is there a usual band height that is normal? Say 1.5mm or 2mm off the finger? What is considered too high or hard to match/uncomfortable between fingers etc?
 
There is really no standard for the height off the finger. My mom's knuckles are very large, so when she rests her finger together, you can see space between the base of her fingers. So, she wears very thick rings, both gemstone and solid metal. My fingers are wide at the base. When I rest them together, I see no light. I tend to prefer things that are not terribly thick.

I think once you start looking for a setting, we can give more concrete feedback.
 
Three more concerns particularly for the aficionado looking for maximum beauty in a stone are transparency, body color and diamond type.
 
Fluorescence is usually fine through Strong Blue in VS and higher diamonds. It can discount th stone in higher colors, making it very desirable in my book. Fluorescence is beautiful but only seen when UV light is present.
 
I will add that I also do not like very high settings, but after having a low setting, I like medium height the most. I felt my diamond looked smaller when set very low, and there’s greater risk of the wedding band rubbing the prongs of the engagement ring.
 
Yes diamondseeker, thank you, I forgot fluorescence. Together with the characteristics mentioned above, fluorescence, particularly blue fluorescence, can make a significant contribution to a diamond's beauty.
 
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