radiant cut, crown height??

[etred]

Had a poor title on my last note, so I''m trying to repost, thanks for the comments everyone.

How important is crown height on a fancy shape. I''ve read all the specs and found a stone online that lands in the 1A category for radiant (64.6 depth, 64 table). It''s 1.17 length to width, but I like rectangle, so it doesn''t bother me that it''s square. But the crown height of 9.7% is graded at a 2B level. Does this impact brilliance so much that I would not want this stone?

So far this stone has been near perfect by every other thing I want in a stone.

thanks

 

[limey]

Good idea to repost hopefully the resident radiant fans will see the thread this time. In the other post you mentioned that you found this diamond online and I don't believe you have seen it yet. I think you might see a common theme in the responses that fancy cuts should be viewed before buying, or at the very least purchased from an online store with a great reputation that is willing to provide you with photos, scope pictures as well as act as a truthful pair of eyes for you.

To keep the thread together and hopefully help people searching for radiant info I will paste and edit my previous response...

I looked into radiants, even had some of the "Original Radiants" brought in to review at a few stores. I ended up not finding one that impressed me as much as I had hoped. At the time I was comparing them to the HOF Dream diamond (ended up going in a different direction).

Anyway, I saw one that was very good and what was most noteworthy was that it had a generous crown around 13% and what a difference it made. 9.7% will be borderline. I took away from this that crown height was VERY important with Radiants.

Look here for another view on optimal measurements for a radiant:
http://www.radiantcut.com/images/optimal.html

(be careful not to interpret 9.7% as excellent, first they use adjusted numbers, as is explained on that page, second I saw RCDC stones with lower crowns, i.e. below 11%, that were not as nice).

 

[valeria101]

It would be great to compare these stones by brilliance. I suppose that the AGA and Gorsbard numbers are set to give some approximation of what parameters result in great light return, but these numbers do not cover all the critical details of the cut (neither they could, since such measurements are not practical to obtain and interpret). So, maybe an Ideal Scope would help?

It would be a pitty to pass a real winner if either the seller does not provide other stones for immediate comparison or the numbers fall just off the top bracket. As far as I know, each AGA class can hide highly brilliant stones. and with one stone in hand statistics might not be as relevant as a simple ranking o light return (with the Iscope providing the lest costly and time consuming version...).

Just my 0.2...

 

[etred]

Thanks!

I have not seen the stone personally. The dealer compared 4 stones all around the same range and this one stood out as the most brilliant. So that was a vote of confidence. But it is all online.

I asked about brilliant scope and light return analysis. I am working with US certd and I've read good things about them on pricescope... and they did not have that information and said many dealers do not for fancy shapes. So it would have to wait until I get the diamond appraised.

the gamble of dealing online.

once again thanks for all the insights..

 

[Nicrez]

In my hunt, I noticed the same thing as andr3wpd did. Higher crowns make the stones have both fire and sparkle.

It's important that is not be cut all table and no crown, as that gives it a more dull and dull appearance. This will also cause the stone to face up larger than it should for the carat weight, and MAY make it look a bit more white and sparkly.

Your stone specifically is cut within the parameters of a 1A, because it's efficiently cut for depth, but the table was cut to keep the "look of size" in the stone, so if the table where smaller, say 62% or so, that would have a higher crown to match and may have hit a 1A on the dot. Does this make this stone ugly? No.

But it may have a bit less fire than if it had a smaller table, and will possibly be a little whiter looking, with less colored sparkles than some. This may actually be the best in your eyes, and I think this stone could be absolutely lovely. I may also possibly exhibit some leakage in the center, but since the #s are fairly close, it won't be extraordinary. Again, this stone HAS potential, so take a chance on it.

I'll tell you right now, finding a 1A cut is RARE, and nothing will ever be perfect on a Radiant (even Grossbards) It's not a roundstone that is cut so frequently it's easy to get the minute dimensions just right. It's a specialty stone, and as such you SHOULD always see it... Just my $.02... Good luck!