There's not much fire in my diamond

[diagem]

And for the sake of clarity, precision-cutting is not H&A, and the way it is taught to be analyzed.

I'm perplexed by this statement. Precision-cutting =\= H&A?? I thought you can only get H&A with near perfect symmetry.
How do you define precision-cut?

Thanks!!

As I fully agree with Paul's statement "By far, the most important factor in observing Fire is precision-cutting..."
Precision cutting levels are greatly dependent on the physical toolings used and data accuracy offered by various technological tools.
Unfortunately today's solution have pretty wide margins of error thus limiting cutters accuracy abilities.
I think precision cutting is H&A but is definitely not 3D optical precision (which I believe Paul meant btw).
In order for a cutter to conquer its limitations, he/she must be able to visually pick up on the errors caused by the tool's margin of error and be able to correct them.
At this point we are talking new cutting philosophy. Extremely complicated to educate old-school cutters to change their old habits, a must in order to enter within technology's errors.

Once a cutter has reached this level of understanding in conjunction with great physical cutting abilities, they are able to cut to optical precision levels that can be analyzed, even on-line. That's where I disagree with Paul a bit.

Although still in its preliminary development stages, Real ETAS is the only tool which lets us analyze the true (3D) optical precision (which is a grand word and this is not the thread for this discussion), in fact, I believe the all the information necessary on a Diamond cut can be read from Real ETAS. It needs a lot of further research & development though.

 

[OoohShiny]

Before the upgrade, I had a 0.61, E, VVS2, GIA xxx,
0.90 carats, GIA XXX
34% crown angle
40.6% pavilion angle
80% LGL

By far, the most important factor in observing Fire is precision-cutting, as it increases the size of the virtual facets, as a result increases the likelihood of Fire being observed. And for the sake of clarity, precision-cutting is not H&A, and the way it is taught to be analyzed.

Paul,

Sorry to breakup your promotional parade but which one do you think will have larger virtual facets in the arrows, a "Superideal" 0.61Ct or the 0.9Ct stone the OP exchanged?

Hint: You have all the information online needed to answer this question its not even close.

I posted a while back requesting evaluation of a diamond we were considering upgrading to. Brilliant Earth didn't have an ASET or ideal scope image, but all the cut proportions fell into the super ideal category and so we went forward with the upgrade because I couldn't find another stone in our desired size and price range that had those super ideal cut proportions.

Before the upgrade, I had a 0.61, E, VVS2, GIA xxx, and we bought it before I knew anything about complimenting crown and pavilion angles. I can't remember the exact angles now, but my diamond sparkled like crazy. Even guys at work would compliment how sparkly it was, and I feel like guys don't usually pay attention to that. These compliments were in the worst fluorescent office lighting too.

Well, I knew my crown angle and pavilion angle on the new stone both fell on the shallower end but it was the only stone I could find in our price range with any proportions that fell in the ideal CA/PA proportions. Here's what we got:

0.90 carats, GIA XXX
F Color
VS1 Clarity
Measures 6.23 x 6.21 x 3.79
57% table
60.9% depth
No fluorescence
34% crown angle
40.6% pavilion angle
42.5% pavilion depth
50% star facet length
80% lower girdle half
No culet
Medium-Slightly Thick Girdle (faceted 4.0%)

I love that I can see the arrows on it, but I'm slightly disappointed at how dull it is. I took it with me everywhere yesterday to play around with it in all lighting, and I got fire out of it like twice. I'm pretty bummed.

You all are so knowledgable with diamonds so I'm posting to see if there's anything wrong with these dimensions. I've attached some photos.

OP if I had to rank the factors that are most likely to affect seeing fire in the diamond it would rank like this:

1) Lighting
2) Lighting
3) Lighting
4) The size of the diamond's virtual facets (Greatest impact is physical size of the diamond!)
5) How clean the diamond is
6) The slight differences in the dispersive properties of the diamond from slight differences in CA/PA combination from GIA XXX 34/40.6 to 'Superideal'
7) The slight differences between GIA XXX and Superideal owing to cut precision exhibited as both 'crispness' and overall average size of virtual facets.

Some of the posts in this thread read like a promotional piece for 'Precision Cut Diamonds' it really shouldn't it is VERY MISLEADING.
It is quite likely you were not viewing the diamonds in the same lighting and/or the 0.9Ct was dirty.

First two posts and on the offensive straight away?

I sense this isn't a normal noob...

 

[Elepig]

A 35 crown angle goes better with a 40.6 pavilion angle. Higher crown angle usually results in more fire.

Back to this for a moment....most of the specs that I have seen of Infinity diamonds*, have lower crown angles - 34.3-34.5.

*Just discovered a vendor in my area is listed as carrying Infinity. I plan on seeing them in person as I'd like some sparkle on my right hand, too.*

 

[OoohShiny]

A 35 crown angle goes better with a 40.6 pavilion angle. Higher crown angle usually results in more fire.

Back to this for a moment....most of the specs that I have seen of Infinity diamonds*, have lower crown angles - 34.3-34.5.

*Just discovered a vendor in my area is listed as carrying Infinity. I plan on seeing them in person as I'd like some sparkle on my right hand, too.*

Definitely go and look at them, I think you'll like them

AIUI, they are cut to balance fire with brightness