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.