Can someone direct me to a % chart?

[sportster]

I am looking for a chart that has the acceptable 'best' ranges of table and depth percentages for Round Brilliant, Cushions (a general idea, I know there are many types) and Radiant.

I anyone has an all inclusive chart link I would REALLY appreciate it!

Also I have a question about blue flor. because there seem to be q's about it today. If I were to get a J stone with medium blue flor. In NATURAL light would it look like a higher grade or only if I was in a UV light? Thanks!

 

[diamondseeker2006]

https://www.pricescope.com/wiki/diamonds/diamond-grading-chart-round

https://www.pricescope.com/wiki/diamonds/diamond-grading-chart-emerald-radiant

With rounds, these are the measurements that I use (and will usually fall into the ideal cut category):

table: 54-58

depth: 60-62.3

crown angle: 34-35

Pavilion angle 40.6-41.0

You have to judge cushions buy pictures and ASET images. There are too many variations in cushions to begin to try to choose my numbers. And in fact, I would want pictures of any stone.

Here is an article on fluorescence. It can make a stone appear a little whiter anytime. But you only see the fluorescent color when under a UV light. I would always choose fluorescence in a stone H color or lower. And in fact, I have had it in F and G and still like it!

https://www.pricescope.com/wiki/diamonds/diamond-flourescence

 

[Rockdiamond]

Hi Sportster,
About fluorescence in general: it's really a case-by-case basis. There are times that a J color with fluorescence shows a blue in almost any lighting, in a positive sense.

But stones like this are more rare than common. In the majority of cases, normal room lighting won't trigger a large effect, but sunlight may.
There are also cases of stones with medium blue fluorescence that is only visible in the dark with UV light.

With regards to charts to be used to guide in selecting diamonds: there is no doubt the charts exist. Even the reasoning behind the charts in many cases is sound. If we are talking about round brilliant cut diamonds, there's an agreed-upon "best" cut.
In general, following the recommendations will allow you segregate these best cut diamonds, when we are talking about round in particular.
When we are talking about any other shape at all, that would be radiant, and, cushion, the charts are of no help at all.
There's a lot of taste involved in many different sorts of light performance that is considered very good by different people. This is markedly different than around us where this is pretty much agreed upon stuff.
For cushion shaped and radiant cut diamond, you really need to look at them to decide which you like.

 

[diamondseeker2006]

Oh, and I totally agree with Rock Diamond that radiants vary greatly in appearance and you do have to at least see pictures. Be careful to always look at diameter measurements when comparing stones that you aren't seeing in person, because some stones are deep and have a smaller diameter and thus look smaller than they should for their weight.