Should I buy this stone? (First time buyer)

[buck_t]

I am buying an engagement ring and want to make sure I am getting a good deal on the stone. I should have the price later this afternoon (my 'diamond guy' is still negotiating the price).

The only details I have are that it is Round Brilliant — 1.31 ct — H — SI1 — Ideal


What would you pay for this stone? Any advice?

 

[chrono]

Nothing. Why? Because I don't know anything about it so I don't know whether it is a fair price, good price or overpriced.

Does it come with lab report? If so, which lab? (To know whether the colour and clarity is as stated).
Who called it Ideal cut? Does not sound like a GIA stone because they grade theirs as Excellent, Very Good, Good, etc.
What are the angles of the stone (table, depth, crown and pavilion)?

 

[buck_t]

I think it's excellent. I don't have the other measurements but it was pretty dang sparkly rock.

$8,300 USD for the diamond.

 

[Diamond_Hawk]

buck_t,

The reason Chrono has (correctly) indicated there is no way to tell how much the diamond is worth is that you have given us some statistics (Round Brilliant — 1.31 ct — H — SI1 — Ideal) with no context and no additional information. The first thing we need to know is who has determined that the diamond is H color and SI1 clarity - there are several reputable labs (GIA and AGS the favorites on PriceScope) who grade diamonds and other labs that are less reliable.

Additionally, there are things that make a diamond 'perform' better - especially round brilliants - in the way that they are cut. An "Ideal Cut" diamond doesn't tell you nearly as much about it as you would like.

Let me give you a sports analogy - hopefully you are a basketball fan.

If you have come to the forum and told us that you want us to help you pick-up a great basketball player for your team and here is what you know: He is a point guard who averages 20 points per game, he weighs 185lbs and you've been told he is Ideal Height and Really Strong.

Should you pick him up? Well, no one knows - we need more information.

Number 1 - In what league is he a 'prolific scorer' - If he averages 20 points per game... High School, Div. 3 college, the NBA? This is like the lab report - a 'prolific scorer' in College Division 3, averaging 20 points per game is much different than the same stats in the NBA.

A GIA report is much like the NBA for grading, but you are potentially playing in a different league entirely with a H/SI1 from a different lab.



Number 2 - Ideal Height <--- again, in what does this mean. Ideal Height in High School could be a 5' 10" point guard, but it is far more likely the measurement will need to be more exacting to play with the 'big boys' in the NBA... 6' 3" or better is more like it.

Likewise - An"Ideal Cut" diamond will be judged by the actual measurements and proportions (Crown/Pavilion Angles, Depth, Girdle size, etc...) and how they function together. These can all be found on the lab report (hopefully from GIA or AGS)



Number 3 - "Really Strong" <--- by which standard. Again, a 'strong' player in Division 3 college basketball would get eaten alive when measured against the best in the world (the NBA). I need to know how many times he can bench-press his weight, how well he positions himself when posting up against other players, and most importantly I'll need to watch some tape and see how he performs.

A diamond is the same way - there are metrics by which the performance of the diamond can be measured (ASET and IdealScope Images) which will tell you far more than "Ideal Cut H SI1" ...

This forum is loaded with great 'scouts' for diamond talent but we will want all of these stats and some ASET and IdealScope images in order to give you our recommendation.

I hope that makes sense and I'm not off-base (to mix metaphors) in helping you understand what we need.

 

[Gypsy]

All diamonds are sparkly under the jewelers lights. They are specially designed to make bad stones look great.

Here is what you need to know:
The entire purpose of faceting a diamond is to reflect light.
How well or how poorly a diamond does this determines how beautiful it is.
How well a diamond performs is determined by the angles and cutting. This is why we say cut is king.
No other factor: not color, not clarity has as much of an impact on the appearance of a diamond as its cut. An ideal H will out white a poorly cut F. And GIA Ex is not enough. And you must stick to GIA and AGS only. EGL is a bad option: [URL='https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/']https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/[/URL]
So how to we ensure that we have the right angles and cutting to get the light performance we want? Well first you want to stick to stones that have a crown angle of 34 (33.5 okay for 60/60 style stones) and over, a pavilion angle of 41 and under, and no deeper than 62.5
https://www.pricescope.com/wiki/diamonds/diamond-cut
Well one method is to start with a GIA Ex, and then apply the HCA to it. YOU DO NOT USE HCA for AGS0 stones.
https://www.pricescope.com/wiki/diamonds/holloway-cut-advisor
The HCA is a rejection tool. Not a selection tool. It uses 4 data points to make a rudimentary call on how the diamond may perform.
If the diamond passes then you know that you are in the right zone in terms of angles for light performance. Under 2 is a pass. Under 2.5-2.1 is a maybe. 2.6 and over is a no. No score 2 and under is better than any other.
Is that enough? Not really.
So what you need is a way to check actual light performance of your actual stone.
That's what an idealscope image does. https://www.pricescope.com/wiki/diamonds/firescope-idealscope
It shows you how and wear your diamond is reflecting light, how well it is going at it, and where you are losing light return. That is why you won't see us recommending Blue Nile, as they do not provide idealscope images for their diamonds. BGD, James Allen, GOG, HPD, ERD and WF do.

The Idealscope is the 'selection tool'. Not the HCA.
So yes, with a GIA stone you need the idealscope images. Or you can buy an idealscope yourself and take it in to the jeweler you are working with to check the stones yourself. Or if you have a good return policy (full refund minimum 7 days) then you can buy the idealscope, buy the stone, and do it at home.


Now if you want to skip all that... stick to AGS0 stones and then all you have to do is pick color and clarity and you know you have a great performing diamond. Because AGS has already done the checking for you. That's why they trade at a premium.

 

[arkieb1]

I think it's excellent. I don't have the other measurements but it was pretty dang sparkly rock.

$8,300 USD for the diamond.

Without meaning to seem rude most of them under great shop lighting look like "pretty dang sparkly rocks" what you need to find out is who the certificate was issued by. If it is EGL run a mile because they frequently misgrade diamond colour and clarity by a long long way (5 to 6 colours and 2 to 3 clarities is common) and you are not getting a deal you are then getting ripped off.

You should also be able to enter the details on the certificate into the HCA which we use as a rejection tool for picking out the best cut stones. Why? Because the better cut the stone the nicer it will appear, stones with better cut appear larger because they have even edge to edge brightness and have more fire and sparkle than not as well cut stones;

https://www.pricescope.com/tools/hca

The lower the HCA the better the cut.