Choosing a diamond seems so complicated. You have to learn about diamond cut specifics, clarity grading, color evaluation, diamond proportions, right?
The truth is that there are some simple rules for selecting a good diamond, and if you follow them, finding a great stone becomes quite easy.
Here we have written a step-by-step guide for selecting the best diamond that fits your budget to help you in the shopping process.
Looking for a place to buy a diamond online? Check out our recommended diamond jewelry retailers.
If you want to know more about how to choose a ring setting in which to put your diamond, read our guide to the most common types of ring settings.
Diamond Buying Guide: A Short Version
Below is the concise version of the step-by-step selection process we recommend that you follow when buying diamonds. For a more detailed explanation of each step, scroll further down for our full-length guide.
Please note that this tutorial is meant to be used for selecting diamonds online, where you can filter and sort stones by price, color, carat, cut, and clarity. However, the principles of selection and judging diamond quality are the same whether you are shopping online or at a brick-and-mortar store.
Step 1: Decide on a shape. The round brilliant is the most popular shape and is the cut that best maximizes a stone’s brilliance. The princess cut is the rectangular analogue of the round cut. These two cuts, along with the cushion cut, are the ones most frequently chosen by shoppers.
Step 2: Set a budget. Think about what you can afford to spend. Then start your diamond selection process by filtering out any diamonds that don’t fall within your budget. For example, if your diamond budget is $4,000, narrow down your search to only stones within the $3,500-$4,000 range.
Step 3: Decide on carat weight. Unless your budget is more than $10,000, we recommend that you initially narrow down the carat range of the diamonds you’re considering to 0.50-2.00 carats.
Step 4: Choose cut quality. Further limit your search to diamonds with Excellent/Ideal cut to ensure that you only look at stones with maximum brilliance and light return.
Step 5: Set minimum color. To exclude diamonds that have visible yellow tints, filter out any diamonds graded lower than J color (I color for side-stone settings and H color for halo settings).
Step 6: Set minimum clarity. Set the bottom clarity cutoff at SI1 to further narrow down the diamond pool to stones that are most likely to be eye clean.
Step 7: Rank diamonds by carat. Sort the pool of diamonds from biggest to smallest to see what are the largest ones you can afford. If you think that the biggest stones in the selection are not big enough, first reduce the minimum clarity to SI2. If that is still not enough, either lower the color minimum or settle for a lower carat.
Step 8: Inspect diamonds for cleanliness. Start with the biggest diamonds in the selection and inspect each one of them for visible flaws, especially towards the center of the stone. Consider every diamond that is clean to the naked eye and big enough a potential candidate for purchase.
Step 9: Examine additional diamond characteristics. Make sure each diamond in your selection has a Fluorescence grade that is None to Faint; Culet should be None to Small, and Girdle Thickness should be from Thin to Slightly Thick. Polish and Symmetry grades should be Good or better. For stones of SI1 clarity or lower, make sure their certificates don’t contain comments indicating that there are additional inclusions not shown on the diamond diagram in the report. Eliminate any stones that don’t fit the above criteria.
Step 10: Compare diamonds and choose. After you’ve filtered out all diamonds that don’t satisfy the minimum quality criteria outlined in the previous steps, you’ll end up with a set of stones that look more or less the same in terms of clarity, color, and brilliance. When comparing them, it’s up to you whether you’ll go for a cheaper or a bigger stone. If two otherwise identical, eye-clean diamonds in your shortlist differ only on clarity and color, pick the better color. Choose at least 2-3 diamonds that are acceptable, as some of them may turn out to be already sold and it’s good to have fallback options.
Don’t want to go through the hassle of browsing through diamonds? Check out our collection of preselected eye-clean diamonds for every budget and pick a stone that we have already vetted.
How to Buy a Diamond: A Detailed Step-By-Step Guide
Below is our detailed guide to selecting a loose diamond. You can add it to your favorites/bookmarks and use it whenever you’re shopping for diamond jewelry. If some of your friends are in the market for a diamond, share this tutorial with them, and they will certainly appreciate your help.
1. Decide on a Shape
Before you start looking at actual diamonds, you should decide what shape you want. The most popular shape by far is the round brilliant, followed by the princess cut.
In this step-by-step guide, we will focus on selecting a round-cut diamond, as this type of stone is not only the most sought after but also the one for which you need to consider the most quality factors.
Most steps in this guide also apply to selecting other shapes, but the recommendations for specific color, clarity, and cut grades differ.
Also check out our diamond cut guide for more information on cut quality.
2. Set a Budget
Perhaps you already have an idea of how much money you are going to spend on the jewelry you are about to buy. Remember to also factor in any import duties (if ordering from overseas), taxes, as well as shipping fees. Don’t forget that your total budget includes the prices of both the diamond and the setting.
In other words:
Total Budget = Diamond Budget + Setting Budget
So, to arrive at your diamond budget, you need to figure out your setting budget.
But how much should you spend on the setting?
To get an idea of current prices of settings, you can go to James Allen, Brian Gavin Diamonds or Blue Nile and check out the offerings there. We recommend that you choose a platinum or white gold setting.
Yellow gold settings are recommended for diamonds of a color grade K, L or M, as these stones’ yellow tint is visible but can be masked by the gold’s color (read more about choosing a setting for a diamond’s color).
Check out our handpicked diamonds for each of the budgets below to see what kind of stone you will be able to afford depending on your spending limit:
- Budget: $1,000-$2,000
- Budget: $2,100-$3,000
- Budget: $3,100-$4,000
- Budget: $4,100-$5,000
- Budget: $5,100-$7,000
- Budget: $7,100-$9,000
- Budget: $9,100-$10,000
- Budget: $10,100-$15,000
Let’s assume for the sake of our example that you’ve selected a platinum setting for $1,000. If your total budget is $5,000, this means that your diamond budget is $4,000, so this is the number we’re going to use to illustrate the diamond selection process.
We will use James Allen’s website for our example here, but the process is pretty much the same with any online retailer that offers loose diamonds.
Now, let’s go to the loose diamond selection menu at JamesAllen.com and set the maximum price at $4,000; let’s also set the minimum price at $3,500 so that we can see a wider selection of stones.
3. Decide on Carat Weight
Now that you’ve set your budget, you can decide on the carat of the stone. Most people want the biggest diamond they can get for their money and end up buying a stone in the 0.50-1.50 carat range.
Read more: Diamond Carat Weight and Size
As it’s best not to settle on an exact carat weight before you know what’s available for your budget, we recommend that you start by working with a carat range and narrow down your choices later.
For our tutorial here, we will initially set the range on the diamond menu at 0.50-2.00 carats.
4. Choose Cut Quality
Now it’s time to set the minimum cut quality. We recommend that you go for the best cut quality, as this is the one diamond characteristic that is so important that you shouldn’t skimp on it. Read more about cut in our Diamond Cut Guide.
Cut determines how light enters the stone and is reflected from its facets. The better a diamond’s cut, the more brilliance and sparkle the stone has, and this is why we recommend that you set the minimum cut grade at Ideal/Excellent.
If you’re wondering what True Hearts means, this is a trademark of James Allen used for Ideal-cut diamonds that are a step above the other stones in the Ideal/Excellent grade, as they are cut to the utmost precision.
5. Set Minimum Color
Next, set a minimum color cutoff. For round diamonds that will be set in platinum or white gold, we recommend that you set the minimum at J color – any lower than that and you will start seeing yellow tints.
The one exception to the above recommendation is if you are going to have the diamond set in a setting with smaller diamonds around the center stone (e.g. side-stone settings, pave settings, halo settings, three-stone settings, etc.). For these settings, set the color minimum at I color (for halo settings – H color).
If you are going to buy a yellow gold setting, you can go as low as K color (or even L/M, if available).
For our example here, we will set the minimum at J color.
6. Set Minimum Clarity
The next step is to decide on the minimum clarity acceptable to you. For now, we recommend that you set the lower end of your clarity range at SI1 – lots of stones in this grade look clean to the naked eye.
SI2 clarity is also a grade in which you can find eye-clean diamonds, but you will need to sort through more stones until you find such diamonds, as most of the stones in this grade are not clean to the naked eye.
We don’t recommend going lower, as diamonds in the I1/I2/I3 clarity range are usually not eye clean.
So, let’s set our minimum at SI1 for now, and we can always go down to SI2 later if we need to.
7. Rank Diamonds by Carat
Now that you’ve set all your minimum criteria for quality, you might want to see which are the biggest stones that fit your budget.
So let’s sort our diamonds by carat, from high to low:
We can see that the biggest diamond we can get with these quality constraints is 1.14 carats, and most other top stones are around 1 carat.
Since in our example we haven’t yet hit the upper carat limit of 2.00 carats we’ve set, the only way we can add bigger stones to our selection is if we relax our minimum color and/or clarity requirements (we don’t recommend that you go lower on cut).
In general, if you want to see more and bigger diamonds, we recommend that you first select a lower clarity minimum and go as low as SI2, but not lower. See if you can find a bigger eye-clean diamond among the SI2 stones. If you can’t, and you’re dead set on a bigger stone, at least try to find a diamond whose visible inclusions are off center and not smack in the middle of the table.
Next, you can relax your minimum color requirement if relaxing your clarity minimum doesn’t yield as big a diamond as you want.
But remember: If you go lower than J color, the stone will look yellowish, and you will have to put it in a yellow gold setting to mask the tint and make the stone look whiter. Only go for a lower color if you’re comfortable with that, but we don’t recommend that you go below M color.
Our recommendation: In most cases, it is not advisable to go for a bigger diamond if this means that it will have visible inclusions and a color grade that makes it look yellowish. Remember that although bigger stones are more visible, so are their imperfections. A 0.80-1.00 ct diamond with no visible flaws or yellow tints will look better than a 1.20 ct yellowish diamond with a visible inclusion.
8. Inspect Diamonds Visually for Cleanliness
After you’ve narrowed down the list of available diamonds to only those that match your criteria, it’s time to start looking closely at each stone. The aim is to decide whether to add it to your shortlist or exclude it from further consideration.
So how do you decide which diamonds are a good choice?
Start with the biggest diamonds and go down the list already sorted by carat, selecting or eliminating diamonds depending on whether they are eye clean.
Eye cleanliness simply means that you cannot see visible defects (e.g., black dots, crystals, lines, etc.) inside or on the surface when looking at the stone through its top side with a jeweler’s loupe. Read more on eye cleanliness here.
So how can you check whether a stone is eye clean? Just look at it and see if you can spot any flaws – lines, dots, cracks, clouds, blemishes – that spoil its appearance.
One good thing about James Allen’s website is that it allows you to look at a real video for each stone and rotate it at 360 degrees. You can use this function to see if there are any visible inclusions.
Pay special attention to whether the central area of the stone is clean of noticeable flaws, as this is the most visible part.
Any stone that doesn’t have inclusions that you can see when you rotate it and look through its top is eye clean – you can add it to your wish list for further comparison.
9. Examine Additional Characteristics of Diamonds
After you’ve shortlisted a selection of diamonds that are eye clean, it’s time to examine their additional characteristics, besides clarity, color, carat, and cut.
Here are the most important additional features you should be paying attention to:
- Fluorescence – the property of a diamond to exhibit a glow, usually blue, under ultraviolet light.
- Culet – the facet at the bottom of the stone.
- Girdle – the thin edge of the stone; its widest part.
9.1. First, check the fluorescence grade for each stone. It should be either None or Faint. Diamonds with Strong fluorescence are likely to appear hazy under normal light.
Stones with Medium fluorescence usually look fine, but some of them may look hazy. To be on the safe side, avoid Medium fluorescence diamonds if their color is in the G-F-E-D range.
For diamonds that are H color or lower, Medium fluorescence can actually improve color and make them appear whiter. So if you’re shopping in that color range, you can actually look specifically for such stones.
9.2. Second, make sure that the culet grade is None to Small. Bigger culets are likely to be visible through the stone’s top and look like a dark hole.
9.3. Third, check the girdle thickness grade – optimally it should be Thin to Slightly Thick. Girdles that are very thin are at higher risk of chipping, while those that are too thick affect the rest of the diamond’s proportions negatively.
9.4. Last, you should check the certificate of the stone for any additional comments under the Comments section, if it exists.
A potential red flag is the comment ‘Clarity grade is based on clouds that are not shown.’ For clarity grades VS1 or higher, this is rarely a concern, but for lower grades, that’s likely to indicate that the diamond may appear hazy.
If you see this or a similar comment, it’s best to ask the retailer for additional information before you decide whether to buy the stone.
Oh, and don’t forget to make sure that the diamond is accompanied by a certificate/diamond report that is issued by either GIA or AGS. Read more about diamond certification here and learn how to read a GIA diamond report.
You’ll notice that diamonds also have grades for Polish and Symmetry. Both should be graded Good or higher. In fact, you could save money by buying a stone that is graded Good on each of these characteristics, as you will be unlikely to be able to tell the difference between that grade and Very Good or Excellent.
10. Compare Diamonds and Choose
The final step in selecting a diamond is to compare the stones you’ve shortlisted and choose the one that you will buy. After you’ve eliminated the stones with quality issues, you will hopefully have at least several diamonds to choose from.
Select at least 2-3 diamonds that fit your criteria, if possible, so that you have backup options if some stones get sold. A diamond can become unavailable even if you reserve it since there is a lag between the time of reservation and the time the wholesaler gets notified to hold the stone. (Oftentimes, the retailer doesn’t stock the stones but works with wholesalers that deliver them quickly on demand.)
When deciding between stones, if you’re comparing diamonds with the same color, clarity, and cut, the choice is pretty much clear: Either get the cheaper one or the bigger one. But what if the diamonds are not nearly identical?
If two similar diamonds differ only on clarity and color, which should I choose?
Let’s say it comes down to two diamonds that are both 1 carat and have an Ideal cut, but one has higher clarity while the other has a higher color. Assuming their prices are close and both are eye clean, which is the better choice?
In such a case, you should first check if they both fit the optimum criteria for fluorescence, culet, and girdle we discussed earlier, and that they don’t have any red flags in the report.
If everything is fine with these characteristics, it is probably a wash. But if you have to choose, we recommend that you go for the better color.
Why not the better clarity? With clarity, a stone only needs to be good enough – i.e., not have inclusions visible to the naked eye. Once that requirement is met, as we assumed for this example, you won’t be able to tell which stone has a higher clarity grade just by looking at the diamond.
With color, you might still be able to perceive a slight difference between grades, depending on how sensitive your eyes are, even if these variations are almost imperceptible. Or, you may not be able to see any difference at all, but you still have to choose one stone and eliminate the other.
Why do diamonds with the same color, clarity, carat, and cut sometimes differ significantly in price?
You can often see diamonds that seem identical but whose prices differ by $1,000 or more. Generally, this is usually because of differences in one or more of the characteristics we discussed above – fluorescence, culet size, girdle thickness, polish, symmetry, as well as slight differences in proportions.
Just follow the guidelines for selection on these criteria that we outlined earlier and you’ll be fine. If it comes down to two diamonds with the same color, clarity, cut, and carat, you can pick the cheaper one as long as it is within the recommended ranges for fluorescence, culet, girdle, polish, and symmetry.
You shouldn’t worry too much about differences in the proportions for depth, table, crown, and pavilion – if the diamond’s cut is graded Ideal/Excellent, they will be within the optimum range. Read more about diamond proportions here.
What to Do If I Cannot Find a Good Diamond?
The best-case scenario would be for you to be able to find a stone that fits all the minimum quality criteria as well as your budget and carat requirements. But in case you cannot find an eye-clean diamond that is as big as you want, fits all the minimum criteria we discussed so far, and is within your budget, you will need to relax some of your requirements.
If you cannot adjust your budget by much, we would suggest that you slightly reduce the carat. We do not recommend that you go for a lower-grade cut because the brilliance of the stone will suffer. Similarly, it is probably not a good idea to compromise on eye-cleanliness or color.
A bigger diamond with visible flaws, low brilliance, or yellow tints will look worse than a smaller but clean, sparkly, and colorless stone.
If you don’t want to go lower on carat weight, there is still an alternative option – you can relax your color requirements and go below J color while having the stone set in yellow gold to make the diamond look whiter.
Another option is to relax your clarity requirement. In such a case, if you cannot find a stone that is eye clean, try to find one whose inclusions are lighter/transparent or are located towards its outer edge and could be concealed by an appropriate setting. You are unlikely to be able to find such stones below SI2 clarity, though.