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How to Choose a Diamond 101

by Haley Anhut
Last updated on September 8, 2023
diamond engagement ring on mirror

Choosing the right diamond is a big deal. With a lot on the line, not just any diamond will do. To make it harder, the process of finding this perfect gem can be overwhelming. Don’t know where to start? We understand, which is why we’ve made this diamond buying guide.

Here we’ll give you a handy crash course in the ins and outs of finding the perfect stone to fit your unique needs. We’ll do this by breaking the information down into sections because when it comes to understanding how to choose a diamond, you’ll want to consider the shape, the 4 Cs, and your budget.


Before you can tackle the quality of your diamond, you need to decide on a shape. In some cases, such as with an engagement ring, choosing a diamond shape might be easy — it might already be decided by the style of the ring or the particular preferences of your partner. If this is the case, feel free to skip to the next section.

If you’re purchasing a diamond for an engagement ring, one of the best places to start is with the round diamond. Not only is this shape simple — a model for classic engagement rings everywhere — it can help increase a diamond’s scintillation and brilliance. Or, in layman’s terms, your diamond will be sparkly. Experts use fire, scintillation, and brilliance to determine how much a diamond will sparkle. 

The second most popular shape for engagement ring diamonds is the princess cut. This is a beautiful square shape that will fit with many engagement rings. Really, it can be hard to go wrong with any of the shapes — most of it is a matter of preference. Just make sure that if you’re choosing a two stone engagement ring, you select two diamond shapes that pair nicely with each other.

Click here for more information on diamond shapes.

The 4 Cs

Once you’ve chosen a shape, your next step is to determine the quality of a diamond. This is a vital consideration, as it not only affects the overall look of your diamond but will also be a major determiner of cost

There’s a common misconception that size is the only indicator of expense. But this is simply not true. The reality is that a diamond’s market value is determined by several factors. It’s even possible to have a smaller diamond that’s valued at more than a larger one, provided that the small diamond is determined to be of higher quality in other categories. 

It all comes down to the 4 Cs: carat, cut, color, and clarity. For a more in-depth look at the 4 C’s, click here


Carat is a unit of measurement created to describe the weight of precious stones and pearls, with one carat being equal to 0.2 grams, or 200 milligrams. Interestingly enough, one carat is also the average size of an engagement ring diamond! Choosing a carat size is the easiest part of the 4 Cs process, you just need to know how big you want the diamond (and/or how much you’re willing to spend). 

In choosing the size of the diamond, you’ll want to take the wearer’s hand size into consideration — larger hands may necessitate a larger stone so that it will be more able to stand out. This is also true for those who already wear a lot of jewelry; you don’t want an engagement ring (for example) getting overshadowed by other, more opulent stones. Finally, you should take the wearer’s activity level into account. Those who work with their hands regularly or who have active hobbies may want a smaller stone, as it will be less likely to get in the way.

Still, unless you’re absolutely obsessed with having a big rock, size shouldn’t be the only consideration.


How a diamond is cut will help determine how sparkly it can be. This grade is given to rough diamonds, not ones that have already been shaped. An ideal cut will allow light to travel completely around the diamond, creating a spectacular glow. In fact, a diamond’s cut is the most important factor in determining its quality in terms of fire, brilliance, and scintillation. 

What we’re trying to say is that there’s a lot riding on what grade of cut you select. If choosing a diamond cut seems intimidating, don’t worry; there are grading systems in place to make it easy to understand.

Groups such as the International Gemological Institute (IGI) rely on a set of industry standards for appraising and grading diamonds. Certified diamonds are graded by experts, which can help guide you in your purchase. And while it’s not strictly necessary to buy a diamond that has been appraised, if you don’t, you will be missing out on an expert opinion on the quality of the gem.

When it comes to the cut of a diamond, the grading system generally stretches from ‘Excellent’ to ‘Poor.’ As you might suspect, an excellent diamond will have a superb cut, as well as a higher price tag, while a poor diamond will have a less effective cut in terms of proportion, symmetry, and polish, and thus will also perform less well in terms of fire, brilliance, and scintillation. It will also have a lower price tag. 


Yes, color is something you will have to consider with your diamond. But wait, aren’t diamonds supposed to be clear

Well, yes, actually, and that’s the point. Lower quality diamonds actually have a yellow or brown tint to them, while high-quality diamonds really are colorless!

Diamond coloring is usually ranked on an alphabetical scale starting at D and ranging all the way down to Z (with D being a colorless diamond and Z being yellow).

If you’re buying a diamond for a ring, it’s also worth figuring out how this coloration works with the rest of the set-up. Sometimes, for instance, the coloration might affect how it sparkles. 

There is good news: Most coloration isn’t noticeable to the naked eye. In many circumstances, even a Z-rated diamond will still look plenty clear. Really, the color will affect how the gem sparkles and interacts with light. The better the color grade, the better chance you have of a properly shining diamond. Color will also affect how multiple diamonds look when grouped together; grouping diamonds of different color grades can produce an inconsistent look. 


Clarity refers to the number of imperfections inside and outside of the diamond. These marks (called inclusions and blemishes) can affect the brilliance of a diamond. Again, like color, these imperfections are rarely noticeable to the naked eye, though they are visible upon closer examination. 

Clarity is perhaps the most confusing diamond rating system, with the best diamonds scoring an FL (flawless) rating, and the lowest quality ones ranking at I3 (Included), which indicates imperfections. Poor clarity can dull a diamond, making it harder for light to travel through. More imperfections lead to less sparkle. 

Also, by now it should come as no surprise that the closer to an FL score you get, the more expensive the diamond will be. For a more comprehensive understanding of clarity, be sure to check out our diamond clarity chart.

Buying on a Budget

No diamond buying guide would be complete without helping you figure out how to choose a diamond on a budget. At the end of the day, choosing a diamond will ultimately come down to price, but with some careful choices, you don’t have to sacrifice quality. 


Of all the aspects you should avoid cutting corners on, the cut of the diamond should be the last thing you negotiate. A good cut can make up for a less quality diamond by providing a shape that is more conducive for light to travel through your diamond properly. Meanwhile, a poor cut can make even a high-quality diamond look bad. 

Ideally, you should shoot for grades “Excellent” or “Very Good.” A grade of “Good” can also be acceptable depending on the shape of your diamond, but our advice is to avoid going lower. Cut is crucial to the brilliance of a diamond, so you should consider reducing other aspects of your gem before going for a cost-effective cut.


It might seem impossible to negotiate how big your diamond will be. After all, size is the one thing most people notice right away, right?

Not necessarily. 

One tip is to buy a diamond just slightly smaller than you planned. For instance, hoping to buy a one-carat diamond? 0.9 carats will not only be cheaper, but the size difference is so small that you’re unlikely to notice the difference without busting out a scale. Also, buying diamonds in carats that don’t align with traditional sizes (like 1, 1.5, etc) may even allow you to snag a discount, because these diamonds may be more difficult to sell.

Need a bigger downsize? No problem! There are tricks to make a smaller diamond seem larger than life. For example, the marquise cut can help your diamond look bigger. Smaller accent gems on a ring can also give the illusion that the main diamond is large. These accent gems can also add sparkle!

Luckily, carat size doesn’t have to be the first thing on the budget chopping block! There are still a few other tips to help shave off costs without shaving down your diamond. 


Fun fact: Most diamonds are flawed! The average diamond actually falls into the “slightly flawed” range of the clarity grading range. These slight flaws generally aren’t noticeable without a microscope, and they don’t significantly affect the brilliance of your diamond.

If you’re worried about budgeting, clarity should be the first thing you reduce. A flawless diamond is going to be way more expensive and, unless you’re a gem expert, probably not worth the extra cost. When you start your initial budget, try aiming for a VS1-VS2 score, which will produce a good looking diamond for a fraction of the price.


They say comparison is the thief of joy, and when it comes to diamond colors, that’s true. Most people really only notice the slight coloration of a diamond when it’s placed next to another diamond! Color is also more noticeable with the size of your diamond. The smaller the diamond, the further down the color scale you can go without it standing out too much. Not to mention, when a diamond is on a ring, much of the color can be masked.

What does that mean in practical terms? With D as the highest color grade your diamond can receive, you can actually aim for anything from G through J ranked diamonds and still get a beautiful, seemingly clear diamond — provided that you don’t surround it with other diamonds of different color grades. In fact, after clarity, color is the easiest aspect of a diamond to sacrifice in order to hit your budget.

Lab Grown Diamonds

Worried about sacrificing too much for your budget? There is another way to get a gorgeous gem at budget price: consider a lab grown diamond! These diamonds might be lab grown, but not only are they chemically and physically identical to real diamonds, but they’re also created using economically and environmentally friendly processes. The end result? Beautiful, real diamonds, that are usually 20-50% less expensive than mined diamonds. Click here to shop affordable lab grown diamonds

After all, choosing the right diamond is a big deal, but it doesn’t have to be difficult. Keep these considerations in mind, know your budget, be aware of what aspects of the diamond are worth paying extra for (and which ones aren’t), and you’ll be able to find the right diamond for any special occasion.