Your Complete Guide to the Perfect Round Diamond At Brilliant Earth

In this article I will show you how to not only find diamonds which have excellent light return but which have the optimal proportions for excellent fire, good contrast, scintillation and how to look for optical precision.

Online shopping is great, isn’t it?

It just takes a few clicks and you can own a beautiful diamond to treasure forever.

Simple right? Well, yes, and no.

You certainly can buy a beautiful diamond in a few clicks.

You can also spend a long time trying to decide on which diamond to pull the trigger on.

The huge selection available today is great! But it’s all too easy to get analysis paralysis.

But don’t stress.

Here I show you how to narrow down your search to end up with a diamond you will absolutely love, love, love!

Why Brilliant Earth? See: An Environmentally Sound Choice: 6 Reasons Why You Will Love Brilliant Earth

Where To Start (Before Searching)

I know everyone wants a shortcut, and I can’t blame you. There are so many fine details which you may think you can skip past. Sorry to break it to you, but no, you really can’t.

Don’t worry, I will try my absolute best to make it as easy as 1-2-3.

Either way there’s no way around needing to get to know the basics. You’ll find that you have to learn just a couple of things about diamonds before you can make your final decision.

Get To Know Diamond Jargon

If you don’t know a diamond from a bar of soap then head on over to Brilliant Earth’s education page. Make sure you drill down to the pages on each of the 4 C’s, and do not skip the page on diamond cuts. They explain a great deal of what you need to know and this will also help you get familiar with some of the diamond jargon.

Think you’re ready? Take The Diamond Quiz

The Easy Way

Brilliant Earth make it easy to quickly sort through diamonds by how well a stone should return light according to its proportions. They do this by labeling each diamond in their inventory with Brilliant Earth’s predefined categories based on light return. They have created five categories: Fair, Good, Very Good, Ideal and Super Ideal.

The better the light return the higher Brilliant Earth rates the diamond.

💡 Diamond is a unique and almost “magical” stone. It acts as both a window and a mirror. So light entering the diamond, can be reflected back from the inside of the stone. Light also slows down when it travels in a diamond. Each frequency (each part of the color spectrum) is reflected back at a slightly different angle when light bounces off the inside of a diamond. This is why you see colorful flashes from a diamond. To read more on this see The Fascinating Science of Diamond Fire.

Diamond Search

Let’s go over step by step how to choose the nicest, sparkliest, brilliantest, shiniest stone, without paying for features you don’t need.

Open up Brilliant Earth’s diamond search page.

The default selection is natural round brilliant when you open the diamond search page.

I know, I know, you may be thinking that it looks like you need a pilot’s license to proceed.

Don’t get overwhelmed by the myriad of choices.

Soon you’ll be flying like a pro.

You’ll get to know what each and every slider and button is for and how to use them.

Since this article will focus on natural diamonds I have the Natural button selected.

💡 There are some very subtle differences when it comes to choosing natural as opposed to lab diamonds, but that is mostly related to color and clarity.

💡 Rules on cut proportions apply across the board to both natural and lab grown.

The Ideal Proportions For Round Brilliants

Since light always bounces off a surface in a predictable way we know that certain proportions will generate the best results.

deep, shallow, and ideal diamond depths

The depth is very important, but so is the table size as it dictates how light both enters and exits the stone.

While there’s room for some debate, there are certain proportions that just work.

The following diagram shows the proportions which have never failed me:

Ideal proportions for round brilliant cut diamonds

This is based on the research done by GIA and AGS some of which you can read here: The Study That Revolutionized What We Know About Diamond Fire.

Clarity Grade

Eye clean diamonds are ones which have received a clarity grade of VS2 or better.

💡 To read more on the definition of eye-clean see What is an Eye-Clean Diamond and What Does it Mean Exactly?.

Of course some people can’t stand the thought of any inclusions in their diamond and will insist on VVS1/VVS2 diamonds. Well you do get bragging rights with that level of clarity. But just be aware that VS2 is almost always perfectly fine.

Clarity is often associated with purity, and this is another reason some people have for choosing higher clarity.

So if someone asks me, I say choose VS2 clarity. But I also recognize that everyone will have their own preference. I’ve even had some clients who really wanted a stone with visible clarity characteristics.

This is the “sweetspot” where you aren’t paying for clarity you can’t see.

My recommendation is to adjust the slider to start at VS2 diamonds. And go from there.

Color Grade

Some people are very color sensitive. If that is the case for you or your loved one I would recommend H color or better. That means D, E, F, G, and H.

If you can’t find anything within your price range I generally recommend to dropping the carat weight first before going too low in color (and clarity).

After all we are looking for stone to treasure forever!

I wouldn’t settle for something inferior.

Just because some stones are cheap doesn’t make them a good deal.

Remember that you get what you pay for.

H and above should be selected for near colorless to colorless diamonds

Polish and Symmetry

I always choose “Excellent” for both Polish and Symmetry. These are both important attributes that contribute to a diamond’s beauty.

Don’t underestimate the importance of excellent polish and symmetry


Since the diamond industry considers fluorescence to be an undesirable trait diamonds with strong fluorescence tend to be priced a little lower. The reason has to do with the risk of the diamond looking milky or hazy when viewed under certain types of light including, but not limited to, sunlight.

Even if it’s only a small percentage of diamonds which exhibit this trait the safest bet is to select diamonds with faint to no fluorescence.

The safe bet to ensure you don’t end up with a diamond that looks milky/hazy under UV light

Depth and Table Range

As shown in a diagram above these parameters in round brilliant diamonds’ table and depth produce optimum brilliance and fire.

These proportions return the best performing diamonds

Extra Options

Brilliant Earth has a number of advanced features allowing you to choose from several specified sources.

Options which are available to those interested in knowing the provenance of their stone.

To find out more about what these options mean please see my article titled: An Environmentally Sound Choice: 6 Reasons Why You Will Love Brilliant Earth

Optical Precision

Once you’ve made all your selections you will instantly see a list of all the diamonds which meet the selected criteria.

Hover over each diamond and scan for a distinct snowflake pattern.

This diamond caught my attention and would warrant a closer look. Notice the distinct arrow pattern.

A distinct arrow pattern allows you to see both the optical precision of the stone as well as the reflective angle of the pavilion facets. The dark arrows shows that the narrowest facets are the ones reflecting the viewer/camera which allows for greater light to be returned from the rest of the pavilion facets. It is also something which makes the diamond look mesmerizing and interesting. Surveys have shown that this feature is common in diamonds which respondents considered beautiful.

Send in your question

If you are looking for a diamond at Brilliant Earth but are having a hard time deciding don’t hesitate to contact me.

As an affiliate I am motivated to find the right purchase that is perfect just for you.

Thomas J Stevens GIA DG CSG

You may also like...

Leave a Reply