The 9-Step Guide to Buying a Diamond

Tips for buying your diamond engagement ring to get the best bang for your buck

Michael Fried
Michael Fried

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    We are reader-supported. Buying through links on our site may earn us commissions. Learn More.

Why this Diamond Guide?

One of our readers was working with Annie recently and asked her about this diamond from Blue Nile. Now her first reaction was that the diamond was stunning. but then she asked what setting it will go in. When the reader responded with this setting, we realized that buying this diamond would have been a terrible mistake.

Here’s what we’ll cover in this article:

How to Pick a Diamond
Choose Your Diamond Shape
Select Your Diamond Carat Weight
Select Your Diamond Cut Quality
Select Your Diamond Color Grade Range
Select Your Diamond Clarity Grade Range
Compare Similar Diamonds
Verify the Diamond Lab Certificate
Get an Expert Opinion

This article is for anybody looking to buy a loose diamond (either by itself or with an engagement ring as a “build your own” set) online at one of the many online diamond vendors.

Sometimes I forget just how difficult it is for a consumer to juggle all the information when figuring out if something is a good price. My team and I have so much experience selecting diamonds (each of us selects hundreds every month), navigating the minefield becomes second nature for us.

For example, if you were to ask me for a 1 carat round brilliant cut diamond to put in a halo engagement ring, it would take me about 15 seconds to find this gorgeous diamond on James Allen for you. Another 20 seconds, and I’d add this great alternative on Blue Nile. But searching on your own can be excruciating and filled with doubt. If you want a little peace of mind, feel free to contact us for some personal advice.

If you’ve been around our site before, you’ll see that we generally recommend buying from Blue Nile or James Allen.  For an explanation of why that is, you can read our individual site reviews for James Allen and Blue Nile.

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How to Buy Diamonds

Choosing a beautiful diamond involves narrowing down your shape and selecting high-quality options for the 4Cs — without overpaying. We’ll go into the four Cs in more detail below, but for now, they are:

  • Cut quality
  • Color
  • Clarity
  • Carat weight

You’ll then compare individual diamonds to see which one offers you the most brilliance and fire. Follow our step-by-step guide below to find a stunning diamond while staying within your budget. Budgets can vary a lot from one person to another, so make sure you’re comfortable with the money you want to spend (for example, if your budget is around 4k, hop in our $4000 diamond engagement ring article after you read this 9 step guide to get inspired). 

We recommend reputable online diamond jewelers. Based on our years of experience, James Allen and Blue Nile have proven to offer the best selection at the best prices (see the full list of Best Online Jewelry Retailers here).

Because their overhead costs are low and they don’t keep an inventory in-house, you’ll find the best deal with these two retailers. Both James Allen and Blue Nile provide HD and 360° imagery so you can compare diamonds up-close before purchase. 

With this key information out of the way, let’s get started with the most important steps in the process of buying a diamond.

1. Choose Your Diamond Shape

The shape of your diamond is the launching point of your ring’s design. No shape is better than the other—it’s up to your personal preference (or your partner’s). Round Brilliants are the most popular diamond shape for engagement rings and give off the most brilliance.

Pro Tip: You may have heard that round diamonds are the most brilliant shape. And that is true (we say it as well). But that is only one aspect when purchasing a diamond. Your own personal style matters most. If you had your heart set on a cushion cut halo, the difference in brilliance between this stunner from Blue Nile and this round diamond won’t be that noticeable.

Others prefer a more unique shape like a Cushion Cut or an Oval. If you’re unsure what your partner prefers, you can ask her family and friends.

It’s important to choose your desired shape first, since this will determine the target parameters for cut quality, color and clarity. Select a shape to narrow down your search and compare diamonds.

Choosing a diamond shape on Blue Nile

Choosing a diamond shape on James Allen

2. Select Your Carat Weight

Is your fiance-to-be expecting a 1 or 2 carat diamond? Are you looking for a stone that’s noticeable but not over the top? There’s no “perfect” carat weight for a diamond, meaning this part of the process is completely down to your personal preferences.

Choose the carat weight range you’re open to considering, such as a 0.95 to a 1.08ct diamond. As carat weight increases, so does the price.

Blue Nile:

How to choose carat weight on Blue Nile

James Allen:

How to choose carat weight on James Allen

Carat weight impacts how large a diamond will appear (as does its shape and cut quality). You can learn more typical carat weights and diamond sizing in our guide to average diamond size to help you make an informed buying decision.

3. Narrow Down on Diamond Cut Quality

The aspect that most greatly impacts a diamond’s beauty is its cut quality. Cut grades aren’t standardized across all retailers, but in general, we recommend only Excellent (if a diamond comes with a GIA certificate) and Ideal cut (if graded by the AGS) diamonds. 

You can limit your search for these cut quality grades using the tools provided by our trusted online diamond vendors.

For example, on Blue Nile’s site for round diamonds, you should limit your selection to Ideal and Astor Ideal diamonds. On James Allen, choose Ideal and True Hearts cut.

How to choose diamond cut on Blue Nile and James Allen

Our Advice

Our advice for cut grade is this: If you are looking for a round brilliant diamond, only search for “Ideal/Excellent” grade diamonds.  If you are searching for a fancy shape, however, then it might pay to either include “Premium” or to disregard the cut grade altogether.

This is not to say that cut grade is not important – on the contrary, it’s of utmost importance. It’s simply saying that many jewelers don’t correctly report fancy shape cut grades, so why filter out many results from your search which might be great choices.

https://www.youtube.com/watch?v=G_y44frw9I0u0026rel=0

4.Determine the Correct Diamond Color Grade Range

The goal with diamond color is to choose a diamond that appears white. But contrary to popular belief, you don’t need to pay for a D or E diamond to get a colorless stone. In general, diamonds in the G to I color range appear colorless to the naked eye, but cost far less.

It is important to remember that different shapes reflect color at different strengths, so your choice of optimal color, balancing the diamond’s appearance with the diamond’s price, will depend greatly on what diamond shape you’ve chosen.

How to choose diamond color on Blue Nile

How to choose diamond color on James Allen

5. Select Clarity Grade

For Clarity, you should look for a diamond that’s eye-clean, meaning you can’t see any blemishes or inclusions with the naked eye. Depending on the shape, you can usually find an eye-clean diamond in the VS1VS2 range. There’s no need to pay for a FL/IF diamond when you can get a lower graded diamond for much less.

Selecting Clarity grades on James Allen and Blue Nile

With most jewelers, you can see the diamond up close to review its clarity. For example, with James Allen’s “Virtual Loupe” you can evaluate a loose diamond before you buy it.  Blue Nile has also begun to offer high quality photography. Look at the diamond closely to see if you notice any blemishes.

For an informative overview of the different clarity grades, take a look at this diamond clarity chart.

Eye-Cleanliness is Paramount

In our opinion, a consumer’s goal should be to find the cheapest (in regards to clarity; other factors matter as well) “eye-clean” diamond you can find. We use “eye-clean” to describe diamonds that may have inclusions if you look at them with a magnifying glass (or microscope or loupe), but the typical person can’t see the inclusion with their naked eye.

eye-clean diamond

We have recently developed Ringo, a patented artificial intelligence model, that can examine videos of diamonds and determine if they are eye-clean. Ringo will also filter for other parameters like making sure the diamond is well-cut, doesn’t have fluorescence issues and will match the style setting you choose. 

Ringo Approved Eye Clean Diamonds

What is Ringo?

6. Compare Similar Diamonds

Once you’ve narrowed down your preferred specs for a diamond, compare similar stones to determine which one to buy. You’ll want to consider aspects like how brilliant the diamond is, if it’s eye-clean, and what the price is in comparison to similar diamonds.

Blue Nile Visual diamond selecting

James Allen visual diamond selecting

Blue Nile selected diamond

James Allen selected diamond

Other characteristics like fluorescence, polish, and symmetry affect a diamond’s value and appearance to some degree, although much less than the 4 C’s. For an in-depth discussion of these three factors, check out these individual articles: Fluorescence, Polish, and Symmetry.

7. Verify the Certificate

Diamonds are evaluated and graded by professional labs, referred to as grading entities. These are the organizations that give each diamond its specific cut quality, clarity and color grades (as well as many others).

Some diamond grading labs are extremely strict and consistent, while others have questionable standards and are much less reliable. You should consider only GIA Certified Diamonds and AGS Certified Diamonds in your search for a loose diamond.


Verify GIA on Blue Nile

Stay away from IGI, EGL, and HRD grading reports because we’ve found in our professional experience that their results are not reliable due to their inconsistent diamond grading. Also, do not confuse GIA reports with an appraisal by a GIA gemologist. Those are not the same thing.

You can learn more about GIA diamonds here.

Verify GIA on James Allen

Luckily, James Allen and Blue Nile both make it easy to limit your search to GIA or AGS certified diamonds. 

On James Allen, click the “advanced options” button under the other diamond parameters, then select the “GIA” and “AGS” checkboxes:

James Allen Certificate Filter

With Blue Nile, all loose diamonds are certified by the GIA, meaning there’s no need to filter out diamonds with lower quality certificates from your search.

8. Choose an Engagement Ring Setting

Engagement ring settings range from elegant and simple, like the solitaire setting, to ornate and eye-catching, like the halo setting. Each setting offers its own unique identity, as well as distinct advantages and disadvantages. 

For example, simple settings such as a solitaire ring are very affordable and great for creating a visual focus on the center diamond itself, while settings that contain halo diamonds can produce the appearance of a larger diamond. 

How to choose a setting on Blue Nile
How to choose a setting on Blue Nile

There’s no “best” engagement ring setting, nor is there any “four Cs” for settings — instead, this part of the process is totally subjective. Choose a setting that matches your tastes, preferences and budget and complements the diamond you’ve selected. 

Follow our insider tips for how to determine the type of setting she’ll love

Our full list of ring settings and styles covers all of the most common engagement ring settings, as well as their major pros and cons.

9. Make the Purchase

Finally, once you feel confident in your diamond, buy it online along with an engagement ring setting of your choice.

With most online jewelers, they offer hassle-free returns within 30 days. If you or your partner aren’t 100% satisfied with the ring, you can get your money back. Almost every reader that goes through our process for picking a diamond is extremely satisfied with their purchase.

Where to Buy an Engagement Ring

If you’ve read our guide to the best places to buy an engagement ring, you’ll know that we’re big believers in purchasing your ring online. 

Buying online has several advantages. The biggest is that you’ll get significantly better value for money due to the economics of e-commerce vs. brick-and-mortar retail. In our experience, most brick-and-mortar jewelry stores charge anywhere from 30 to 100% more for their diamonds than trusted online vendors. 

The second advantage of buying online is that you’ll have access to a vastly larger inventory of both diamonds and settings. This larger selection makes it easier to find a diamond that meets your specifications.

We recommend buying from the following trusted vendors:

  • James Allen. James Allen provides a massive selection of diamonds and settings, with fantastic customer service and excellent pricing. They also have detailed 360° imagery that makes it easy to check diamonds for inclusions and color.
  • Blue Nile. Blue Nile offers the largest selection of diamonds of any online vendor, with highly competitive pricing and fantastic customer service. Along with James Allen, they are a great choice for diamond engagement rings in all price ranges.
  • Brian Gavin Diamonds. Brian Gavin is an industry leader in diamond cutting. Buying from Brian Gavin Diamonds is an absolute treat if you’re looking for a diamond with an outstanding level of brilliance and fire.
  • Abe Mor. Abe Mor offers excellent high-end, fine jewelry. They specialize in large and rare diamonds and are a great option if you’re looking for an exceptional engagement ring and have a budget of $50,000 or more.
  • Leibish & Co. Leibish & Co. is our go-to company for fancy color diamonds. They offer an incredible selection of stunning fancy color diamonds in all budget ranges, including blue diamonds and black diamonds.

Diamond Ring Insurance

A diamond ring is a major investment, and like other valuable possessions, it’s something that you’ll want to insure. 

If you have homeowner’s or renter’s insurance, you might be able to add your engagement ring to your existing policy. It’s best to contact your insurance carrier to check if your diamond ring is covered, and if not, if it can be added to your existing policy at an additional cost.

Our guide to insuring your diamond engagement ring provides more information about how you can insure your engagement ring and other jewelry. 

Some diamond vendors also offer insurance coverage. For example, James Allen and Blue Nile provide the option of insuring your engagement ring through partnerships with Jewelers Mutual, a personal jewelry insurance company that’s been around for over a century.

You can see James Allen’s insurance offering here and Blue Nile’s engagement ring insurance offering here.

Don’t Forget the Engagement Ring Size

Although it is possible to resize an engagement ring after purchase, one additional step that we highly recommend taking is working out your partner’s ring size before buying your engagement ring. 

Online diamond vendors like James Allen and Blue Nile make this part of the process easier by providing free ring sizers that you can use to work out your partner’s exact ring size before you place an order for your ring.

This is the safest way, but it’s not always the most romantic, especially if you want to keep your plan to pop the question secret. We’ve shared a few other techniques that you can use to work out your partner’s ring size without raising suspicions in our guide to finding your ideal ring size.

Trusted online vendors such as Blue Nile and James Allen also offer free resizing for almost all engagement ring settings, meaning it’s usually not a big deal if you make a minor sizing error.

Need Help Buying a Diamond Ring?

We understand that buying a diamond ring can be a confusing and stressful process, even with the information above. Diamonds are costly, and trying to find the perfect balance of cut quality, color, clarity and carat weight without exceeding your budget isn’t easy. 

If you have any questions throughout the engagement ring process, feel free to reach out to us for diamond advice. We help hundreds of our readers find and buy beautiful engagement rings every month, and our diamond experts are happy to answer any and all of your questions. 

James Allen James Allen is the leader in online diamond sales. Their imaging technology is the same as inspecting a diamond with a jeweler's loupe. They have the largest exclusive loose diamond inventory online and fantastic prices. They also have the nicest collection of lab created diamonds online.  Save 10% off select lab grown diamonds and 25% off ring settings during limited time sale!
What we love about them:
  • No questions asked returns within 30 days of shipment. James Allen will send you a paid shipping label to return the ring.
  • Lifetime Warranty
  • Free International Shipping
  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisals
  • One free resizing within 60 days of purchase
  • Free ring inscriptions
  • Best-in-class high quality imagery of all diamonds in stock
  • 24/7 Customer Service
  • Best-in-class packaging
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Blue Nile [generate_bluenile_links url="https://goto.bluenile.com/c/1323400/504049/8660?u=https%3A%2F%2Fwww.bluenile.com%0A%2F" title="Blue Nile" cta="Blue Nile"] is the largest and most well known internet jewelry seller. They have a very large exclusive online inventory. Their high quality images are catching up to James Allens' and their prices are amazing. Blue Nile have generously offered our readers an exclusive one-time use coupon. [dp-bn-coupon message=" (Click Here to save $100 off $1000 purchase)" type_id="1"]
What we love about them:
  • No questions asked returns within 30 days of shipment. Blue Nile will send you a paid shipping label to return the ring.
  • Lifetime Warranty
  • Free Shipping
  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisal
  • One free resizing within the first year of purchase
  • High quality images of about half of their diamonds
  • 24/7 Customer Service
  • 100% credit towards future upgrades (must be at least double in value)
  • Best in class fulfillment
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