By GrownDiamond Editorial TeamUpdated March 18, 20267 min read
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Cushion Cut Lab-Grown Diamonds: Complete Buying Guide 2026

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Quick Answer

Why choose a cushion cut lab-grown diamond?

Cushion cuts deliver vintage romance with modern sparkle. Their rounded corners and pillow-like shape create exceptional fire (colored light flashes). They cost 10–15% less than equivalent round brilliants and look stunning in both solitaire and halo settings — the most romantic shape in the diamond world.

📊 Cushion cuts account for ~15% of lab diamond purchases. Starting from ~$400 for 0.5ct G/VS2 IGI certified. Approximately 10-15% less expensive than equivalent round brilliants.

Why Choose a Cushion Cut?

The cushion cut has been beloved for over 200 years — it was the dominant diamond shape before round brilliants took over in the 20th century. Today, it's the romantic's choice: soft, warm, vintage-inspired. Their rounded corners create a pillow-like silhouette that looks beautiful in virtually every setting style.

  • Exceptional fire: Cushion cuts produce more colored light dispersion (fire) than round brilliants — the dramatic rainbow flashes are a cushion signature
  • Romantic appeal: The soft, rounded shape feels more personal and vintage than the geometric precision of rounds or princess cuts
  • Price advantage: 10–15% less expensive than equivalent round brilliants
  • Versatility: Looks stunning in solitaire, halo, three-stone, and vintage settings

Classic vs. Modified Cushion Cut

There are two main types of cushion cuts, and the difference matters:

  • Classic cushion (antique cushion): Larger, chunkier facets producing dramatic fire and a soft, romantic glow. Best for vintage-inspired settings. The "chunks" of light are larger and more dramatic.
  • Modified cushion (crushed ice): More facets producing intense, scattered sparkle similar to a round brilliant. More modern-looking. The light pattern is smaller, more numerous, and glittery.

Neither is objectively better — it's a matter of preference. View 360° videos to see the difference in person before buying.

Ideal Proportions

ProportionSquare CushionElongated Cushion
L/W Ratio1.0–1.051.15–1.25
Depth61–67%61–67%
Table58–67%58–67%
Cut GradeExcellent / Very GoodExcellent / Very Good

Color & Clarity Tips

Color: Cushion cuts retain color slightly more than round brilliants — a cushion H may look like a round G. For a white appearance, aim for G or H. If you prefer a warmer tone, I or J cushions are beautiful and significantly less expensive.

Clarity: The many facets of a cushion cut conceal inclusions effectively. SI1 clarity is often eye-clean in cushion cuts — a real money-saver vs the VS2 you might need for an emerald cut.

Pricing — 1ct Cushion G/VS2 IGI

Retailer1ct Cushion G/VS2vs Round
Clean Origin$950–$1,200~10% cheaper
James Allen$980–$1,300~10% cheaper
Brilliant Earth$1,100–$1,450~10% cheaper
Blue Nile$1,000–$1,350~10% cheaper

Frequently Asked Questions

For a square cushion: L/W ratio 1.0–1.05, depth 61–67%, table 58–67%. For an elongated cushion: L/W ratio 1.15–1.25. Look for an IGI or GIA Excellent or Very Good cut grade. Avoid depth over 70% — the stone will look smaller face-up.