When it comes to choosing the perfect diamond for an engagement ring or fine jewelry, cut and size are two of the most critical factors. One of the most unique and elegant diamond cuts is the marquise cut. Known for its elongated, eye-catching shape and vintage allure, the marquise cut offers a regal appearance and maximizes carat weight. In this article, we’ll explore what makes the marquise cut special, and provide a comprehensive Marquise Cut Diamond Size Chart that translates carats to millimeters (mm) and vice versa.
What Is a Marquise Cut Diamond?
The marquise cut, sometimes referred to as the "navette cut" (French for "little boat"), is a type of brilliant-cut diamond. It features 58 facets, with a long, narrow shape and pointed ends. This cut is designed to maximize sparkle while elongating the finger, making it a popular choice for engagement rings and statement pieces.
Key Features of the Marquise Cut:
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Shape: Oval with pointed ends
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Facets: 58 (same as round brilliant)
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Length-to-Width Ratio: Ideally between 1.75 and 2.25
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Appearance: Makes fingers appear longer and slimmer
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Style: Timeless, elegant, often seen in vintage settings
Why Choose a Marquise Cut?
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Maximizes Carat Weight: The elongated shape gives the illusion of a larger diamond.
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Unique Look: Less common than round or oval cuts, it stands out.
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Flattering Shape: Especially flattering on smaller hands or shorter fingers.
Marquise Cut Diamond Size Chart (Carat to Millimeter)
This chart provides average dimensions for marquise cut diamonds based on their carat weight. Please note that actual sizes may vary slightly depending on proportions and depth.
| Carat Weight | Length (mm) | Width (mm) | Approx. L/W Ratio |
|---|---|---|---|
| 0.25 ct | 6.5 mm | 3.25 mm | 2.00 |
| 0.50 ct | 8.0 mm | 4.0 mm | 2.00 |
| 0.75 ct | 9.5 mm | 4.75 mm | 2.00 |
| 1.00 ct | 10.5 mm | 5.25 mm | 2.00 |
| 1.25 ct | 11.0 mm | 5.50 mm | 2.00 |
| 1.50 ct | 12.0 mm | 6.00 mm | 2.00 |
| 2.00 ct | 13.5 mm | 6.75 mm | 2.00 |
| 2.50 ct | 14.5 mm | 7.25 mm | 2.00 |
| 3.00 ct | 15.5 mm | 7.75 mm | 2.00 |
| 3.50 ct | 16.5 mm | 8.25 mm | 2.00 |
| 4.00 ct | 17.0 mm | 8.50 mm | 2.00 |
| 4.50 ct | 18.0 mm | 9.00 mm | 2.00 |
| 5.00 ct | 19.0 mm | 9.50 mm | 2.00 |
Marquise Cut Diamond MM to Carat Chart (Estimated)
If you already have the millimeter measurements and want to estimate the carat weight, refer to this chart:
| Length (mm) | Width (mm) | Estimated Carat Weight |
| 6.5 mm | 3.25 mm | 0.25 ct |
| 8.0 mm | 4.0 mm | 0.50 ct |
| 9.5 mm | 4.75 mm | 0.75 ct |
| 10.5 mm | 5.25 mm | 1.00 ct |
| 11.0 mm | 5.50 mm | 1.25 ct |
| 12.0 mm | 6.00 mm | 1.50 ct |
| 13.5 mm | 6.75 mm | 2.00 ct |
| 14.5 mm | 7.25 mm | 2.50 ct |
| 15.5 mm | 7.75 mm | 3.00 ct |
| 16.5 mm | 8.25 mm | 3.50 ct |
| 17.0 mm | 8.50 mm | 4.00 ct |
| 18.0 mm | 9.00 mm | 4.50 ct |
| 19.0 mm | 9.50 mm | 5.00 ct |
Final Thoughts
The marquise cut diamond is a stunning option that delivers on both beauty and perceived size. Whether you’re shopping for an engagement ring or creating a one-of-a-kind piece of fine jewelry, understanding the carat-to-mm ratio helps ensure you get exactly the look you want.
Use the size charts above to make confident, informed decisions about your marquise diamond purchase.
