Can a "Very Good" Diamond be a Great Diamond?

[ja15]

Hello everyone, and thanks Lorelei and move1986 for your help on the last thread!

I looked at those diamonds, but I'm also considering this H Si1. It's GIA report is attached.

The HCA tool scored this diamond as "Excellent" in every category. It also has a score below 2. I know the HCA is only a screening tool and it's definitely passed the screen. It also looks great in the pictures, but why does GIA categorize this as a "very good" cut diamond only?

My question is - based on it's numbers, is this a sparkly, well-cut diamond? One that perhaps GIA miscategorized? This vendor doesn't provide Aset or IS images.

I'll post this diamond's photo if you think it's necessary, but I prefer not to as I haven't reserved it yet.

 

[teobdl]

Everything else aside, do not buy a very thin girdle. Period. It has a very high risk of breaking.

That said, there are more than a couple readily apparent reasons this diamond got the VG cut grade rather than Excellent.
1. Very thin girdle
2. Shallow crown angle for the pavilion
3. Very long lower halves (this crown-pavilion angle combo would be fine if the lower halves were shorter)
4. Symmetry = good. Only go down to VG symmetry. G in symmetry will drop an otherwise "Ex" cut down to "VG" cut.

This has the potential to be a terrible, dangerous diamond, and I would definitely not spend thousands on it.

 

[teobdl]

But to answer your opening question, yes, a VG diamond can be a great diamond. In fact, there is a subset of AGS 0 cut grade diamonds that would not receive GIA Excellent. This is an exception, rather than a rule.

You need to scrutinize a VG diamond to understand why it may have received the VG cut grade rather than Excellent. Many times it is very apparent, other times it is not.

The best VG is one that is otherwise awesome but just has a thick girdle dropping it into VG. It will be slightly heavier for its weight (ie not face up as big), but the lower cut grade may give you a bigger savings than the extra carat weight costs, with no visibly diminished performance.

 

[Karl_K]

very thin girdle and a lowish crown angle with a 40.8 pavilion are not conductive to longevity.

 

[ja15]

Thanks Teodbl, Karl K.

I'm more familiar with fancy cuts, so I really appreciate the help with RBs.

I'll have a lot more questions too. I hope you don't mind.

 

[Karl_K]

Sure fire away.
I am limited in what I can answer by the trade rules but there are some awesome prosumers here that know more about diamonds than 99.999% of the people in the trade.