What Is Diamond Spread And How Does Diamond Cut Affect Spread?

While carat weight is the most explored factor when buying diamonds, it is important to know that two diamonds with the same carat weight can look different in size.

That’s because of diamond spread, an important factor that is often overlooked.

By understanding diamond spread, you can choose a diamond that offers the best value in size and aesthetics.

Here’s a guide to understand diamond spread and how diamond cut affects spread.

What is diamond spread?

Diamond spread is the face-up size of a diamond, which means how large the diamond appears when seen from the top. It is measured as the diameter of the diamond across the widest point. It is measured in millimeters (mm).

Why does diamond spread matter when buying a diamond?

When diamonds are placed into settings, for example, a finger ring, only the table and crown are visible. The depth of the diamond is hidden in the setting. The spread of the diamond, which is the face-up diameter, determines how big it looks. Hence, diamond spread matters, because:

• It helps compare diamonds of the same carat weight

• Identify diamonds that offer better visual size

• Avoid paying more for a diamond that looks undersized

• Make a smarter, and more informed purchase decision

How is diamond spread measured?

Diamond spread is measured using a millimeter gauge or precision caliper. For round diamonds, it is the average diameter across two perpendicular measurements. For fancy diamond cut shapes, such as oval, pear, and cushion, measurements include both length and width.

Diamond diameter vs carat weight

Did you know, there is an expected diamond range for each carat weight in round brilliant diamonds? For example, a 1 carat round diamond should have a diameter of 6.4-6.5 mm. A smaller diameter means weight is hidden in excessive depth, and larger diameter means it may be shallow.

What is the relationship between diamond cut and diamond spread?

Cut is one of the biggest factors that determines how a diamond’s carat weight translates into its visible size. A diamond with high-quality cut displays maximum spread, whereas a poorly cut diamond hides weight where it cannot be seen.

How do cut proportions influence spread?

The diamond cut proportions include table size, crown angle, pavilion depth, girdle richness, and total depth. Together, these elements determine both optical performance and face-up size. If these proportions are in balance, the diamond reflects light well and offers an ideal spread for its weight.

However, if the diamond cut has more depth, it retains more weight below the girdle. This can make diamonds look smaller than their carat weight. Diamonds cut too shallow, spread wide but lose brilliance.

What role does depth percentage play in diamond appearance?

When comparing two diamonds of the same carat weight that appear to be different in size, depth percentage is one of the first things to check. Depth percentage is the ratio of a diamond’s depth to its diameter. For round brilliant diamonds, the ideal percentage is typically between 59% and 62.5%. Here are some aspects to note:

• A depth below 57% indicates a shallow cut, more spread, but poor light return

• A depth above 64% indicates a deep cut, less spread, with weight hidden underneath

• Depth in the ideal range offers the best balance of spread and brilliance

How does table size affect the face-up size of diamonds?

The table is the large flat facet on top of the diamond. Table size is expressed as a percentage of the diamond’s diameter. For round brilliants, the ideal table percentage is between 54% and 58%. However, many excellent cut stones are 60% to 61%.

A larger table can make a diamond appear slightly wider from the top. However, if it comes at the cost of reduced crown height, the stone may lose its fire and sparkle. Table size alone does not determine spread. It works in combination with all other proportions.

Diamond cut shapes and their impact on diamond spread

Diamond spread characteristics differ based on diamond cut shapes, too. For instance, fancy shapes tend to offer more face-up area per carat compared to round diamonds. Here are some diamond shapes and how they impact diamond spread.

• Round diamonds: A 1 carat ideal-cut round should measure approximately 6.4 to 6.5 mm.

• Oval diamonds: A 1 carat oval can measure around 7.0 to 8.0 mm in length.

• Pear diamonds: A 1 carat pear can measure 8.0 to 9.0 mm in length depending on its length-to-width ratio.

• Cushion diamonds: A 1 carat cushion typically measures around 5.5 to 6.5 mm, depending on cut style.

• Emerald diamonds: A 1 carat emerald cut often measures around 6.5 to 7.0 mm in length.

How to compare diamond spread before buying?

Follow these best practices to compare diamond spread when buying diamonds.

1. Check the millimeter measurements

Grading reports by GIA, AGS, GCAL, etc., will include the diameter measurements. For round diamonds, the average diameter should align with the ideal range for the listed carat weight. For fancy diamond shapes, compare the length, width, and depth measurements.

2. Review the depth percentage

Another step to compare diamond spread is to assess the depth percentage. For round brilliants, look for diamonds with depth percentage between 59% and 62.5%. A percentage above 64% indicates hidden weight and reduced face-up size.

3. Use side-by-side comparisons

Many online diamond retailers, such as Grown Diamond Corporation, have diamond comparison tools. Compare diamonds of the same carat weight next to each other and compare their actual mm dimensions.

4. Request face-up images or videos

A diamond photographed from the top shows its true spread far better than a side profile. Video is even better for assessing real-world appearance.

5. Use a diamond spread calculator

There are many online tools that estimate the expected diameter for a given carat weight and diamond shape, which help to identify whether a stone is deep, shallow, or ideal.

Wrapping up

Understanding diamond spread and comparing diamonds for spread can provide a better sense of the diamond’s quality, pricing, and overall value. Online diamond retailers and lab grown diamond manufacturing brands allow customers to compare diamond spread before making purchases.

Besides, diamond grading reports provided by retailers and manufacturers also mention details about diamond cut, diamond spread, among other factors. If you’re looking to buy high-quality lab grown diamonds with the perfect diamond spread, explore Grown Diamond Corporation.