Diamond FAQ/Reference thread

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#76
Hi All,

You might already know this, but I just found the website for the Holloway Cut Advisor which lets you enter the following measurements from a GIA report and will calculate how brilliant and stunning a diamond will be visually.

Depth%
Table%
Crown angle
Pavilion angle
culet%

It's at the following website and it's free.
http://www.ideal-scope.com/hca.asp

I'm getting a diamond on line and I find it extremely helpful. I've been to retailers who use this tool to help determine brilliance, fire and scintillation (visual options as the guys on goodoldgold keep talking about) when ordering diamonds that they have never seen for their customers.

I've analyzed dozens of diamonds that are graded "excellent" in cut, even triple X, but do not perform that well on this test. Check out DiamondInfoMan on youtube and they explain this a lot more.

Hope this is helpful!
 
#77
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"Whether you’re choosing a diamond shape for an engagement ring, earrings or a just for fun ring, much more goes into it than mere aesthetics. To my horror, there are a host of issues that no one tells you. For example, some diamond shapes hold more weight than others–meaning, for the same carat weight, certain shapes will look smaller because the bulk of the weight is in the lower part of the diamond that is hidden by the setting. Similarly, certain shapes will reflect light better than others due to their shape and cut and as a result, certain shapes will be more brilliant than others or show more fire."
 
Last edited by a moderator:
#79
Cheat sheet which is a great set of numbers for Round Brilliants

And I’d ask the sales person to limit the selection of round brilliant cut diamonds which they offer to me so that all of the diamonds are within the following range of proportions:
Total depth between 59 – 61.8%
Table diameter between 53 – 57%
Crown angle between 34.3 – 34.9 degrees
Pavilion angle between 40.6 – 40.9 degrees
Girdle thickness between thin to medium, faceted (bruted isn't bad, but faceted would be better)
Culet size: none

When you're dealing with a table of 53-54, you want the depth to be in the 59-60 range, not the 61-62 range. I harp on the 55 because it's RIGHT in the middle of the range, and sometimes a 56. The middle of the range is PERFECT, and is always talked about as the perfect table number.

The angles mentioned in degrees are a range, obviously you're going to have interplay, so there's not a specific ratio there. You have to see what the numbers on each stone are. There really is a bigger range of angles than that but ideally those would be great to hit.

Girdle: Bruted isn't horrible, my current stone is bruted. I LIKE Faceted better, but bruted isn't a horrible thing.
 
#80
EpiFanatic said:
Hi All,

You might already know this, but I just found the website for the Holloway Cut Advisor which lets you enter the following measurements from a GIA report and will calculate how brilliant and stunning a diamond will be visually.

Depth%
Table%
Crown angle
Pavilion angle
culet%

It's at the following website and it's free.
http://www.ideal-scope.com/hca.asp

I'm getting a diamond on line and I find it extremely helpful. I've been to retailers who use this tool to help determine brilliance, fire and scintillation (visual options as the guys on goodoldgold keep talking about) when ordering diamonds that they have never seen for their customers.

I've analyzed dozens of diamonds that are graded "excellent" in cut, even triple X, but do not perform that well on this test. Check out DiamondInfoMan on youtube and they explain this a lot more.

Hope this is helpful!
Click to expand...
Wow great tool!
 
#84
I know it's impossible to do when you buy online, but you should definitely try diamonds on at a store first just to see how they look on your hand. I have extremely small hands (ring size 4) and I found that a 1 carat actually looked way bigger on me then I thought it would. Much to my surprise, I was pretty pleased with that size when I had always thought that I really wanted a much larger ring. (Although if you have larger hands it might not work out so well in your favor :nogood:)
 
#90
ame said:
That's unusual to see on a diamond. It's typically on gemstones. It's essentially where the pavilion facets are each cut to be slightly curved. I think Gene Flanagan is usually who known for that.
Click to expand...
Thanks for replying.
I tried to research online but couldn't find a thing.
I will check it out a little further.
I wonder if anyone has ever seen one and what they think of it.
 
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