How to evaluate a diamond by looking?

[adev]

I have been going through PS for quite some time now. It has been a very useful source of information and has provided me a great deal of education on diamonds. Thanks to all the experts for sharing their opinions and for taking time to educate newbies like me.

I understand that for selecting the BR diamond based on its cut, there are some guidelines in terms of table, depth, pavilion, crown %age and angle and there's also the HCA calculator to help narrow down the choices. However, I am wondering if there are some guidelines on how to inspect the diamond visually.

How does someone, who is not a diamond pro, go about determining the quality of a diamond visually without any comparables to look at? Here on PS, I always see the recommendation to check the magnified videos, pictures, ASET and ideal scope images to determine the quality of diamond. But if none of those are available and you only have the diamond to physically look at, what are the things to look for to evaluate it? The GIA excellent cut is a broad range. How can someone visually identify the ideal cut vs super ideal like (H&A, ACA, Signature cut) diamonds?

 

[Rockdiamond]

This is such a great question!!

I think that when looking at a diamond we use different sets of data, and combine them to evaluate.
Here's what I mean:
One side of the brain deals with the statistical analysis.
That would include images ( both reflector and actual), GIA report data, HCA, price, terms of sale

The other part is purely visual.
I love to loupe diamonds, and see all the wonders of nature inside.
But all that close up viewing, combined with the statistical analysis is only 50%.
The rest is "real life" observation.
For me, looking at a stone arms length is very important.
In all sorts of lighting environments. Both in and out of bright store lighting.

This is one reason that an unconditonal money back guarantee is so important- so you can look at home.

 

[adev]

But all that close up viewing, combined with the statistical analysis is only 50%.
The rest is "real life" observation.
For me, looking at a stone arms length is very important.
In all sorts of lighting environments. Both in and out of bright store lighting.

This is one reason that an unconditonal money back guarantee is so important- so you can look at home.

Hi Rockdiamond, what exactly are you looking for under different lighting? How do you spot any problems? What sets super ideal cut stones apart from non-super ideal when seen from an arms length?

 

[Rockdiamond]

Spotting problems:
Another great point- how do you spot problems?
The first thing you need to figure out is, what is a problem to you?

If you're talking about a round brilliant cut diamond, the variation between well cut stones is remarkably narrow. Some differences that are obvious under the loupe are less obvious fro 12 inches- while other aspects you can't really judge in the loupe become more important.
Spread is a very important aspect the's easier to see at 12 inches than in a loupe or photo.
Some important cut variables like the LGF- the length of the facets on the bottom of the diamond make the diamond sparkle in different ways. higher percentage produces narrower facets on the bottom making the sparkle more "splintered". Is this a problem?
For some people yes, but for others shorter bolder LGF's are undesirable.
This is an aspect you can easily see in micro photos, or loupe- but only when you experience the differences from 12+ inches can you appreciate which style you love best.
There's a lot of this that's based on taste.

 

[Gypsy]

In some ways evaluating a diamond in real life is harder than on the net.

The best way to do it is to A) train your eyes and B) go to a good independent jewelry store (not a chain) during the week after making an appointment.

Training your eyes for round brilliant:
Go to a Hearts on Fire dealer. Especially if the Hearts on Fire Dealer has non-ideal stones. Make an appointment during the week (weekends are busy and you won't get the same kind of time to spend).

Compare hearts on fire stones to non-ideal stones. Make sure you see them away from the jewelers lights and in all kinds of lighting conditions (if you need to know how to do this, ask and I'll tell you).

See what your eyes like and don't like. See if you can see why one is ideal and the other isn't.

Honestly, if you can buy an idealscope (25 bucks) and learn to use it, that is a big help for beginners with round brilliants.

And then go from there.

Then when it is time to buy make sure you are working with a great jeweler, that calls in diamonds for you with your specs (we can help you decide what those are), and then spend a lot of time with the stone picking them up and comparing them.

You don't want a hard sell type place. Or a place that doesn't call in stones with your specs for you.