Round Lab Grown Diamond Twisted Cathedral Engagement Ring

IGI Report IncludedMade to OrderInsured Delivery

Portuguese cut round Lab Grown Diamond engagement ring in white gold with twisted cathedral shoulders and a four-prong open basket.

1 of 10

$768.00

Price updates with your selections

Independently graded by IGI IGI Report Included Selected 0.50 ct+ lab-grown center or primary diamond · IGI grading report · Signora Jewelry Certificate included. 1 ct lab-grown diamond · IGI report · Signora Certificate included.

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Center Diamond:

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Forever, A & J

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Complimentary · hand-engraved to order · adds about 3–4 days.

Arrives 7 business days to make, then 5–8 insured & tracked.

30-day returns Courier, insurance & duties covered. No restocking fee.

Duties & taxesPrepaid at checkout. Nothing extra to pay on delivery.

Estimated dispatch: 7 business days Duties & taxes prepaid

Ring size guide

Lay a ring you own flat on the circle and slide until it sits just inside it — or set its inner diameter directly.

Measure the inside of a ring that already fits — inner edge to edge — with a ruler in mm, then set it below. No ring handy? Try Measure your finger.

14 mm 24 mm 17.3 mm

Inner diameter mm

US size

UK size

EU size

Circumference

54.3 mm

Between sizes? Always choose the larger size. Fingers are slightly bigger in the evening — measure then for the best fit.

Method 1 — Use an existing ring

Find a ring that fits the intended finger comfortably.
Place it flat and measure the inner diameter (inside edge to inside edge) in mm.
Enter that measurement in the Measure a ring tab.

Method 2 — Wrap and measure

Wrap a thin strip of paper around the base of your finger.
Mark where it overlaps — measure that length in mm (your circumference).
Divide by 3.1416 (π) to get your diameter, then use the Measure a ring tab.

Tip: Middle finger sizes typically run half a size larger than the ring finger. If between sizes, go up. Measure in the evening — fingers are slightly larger then.

7US size

US	UK	EU	Diameter	Circumference

Highlighted row = your converted size. Most common women's sizes are US 6–7. All measurements in mm.

Selected: —

The Signora Promise

Hand-finished in SuratMade to order

Reports where statedExact scope shown

Insured deliverySigned & tracked

Secure checkoutShopify checkout

Standard-design returns30-day eligibility

Final inspectionChecked before dispatch

About This Ring

Round Brilliant · Solitaire

Center

Round Brilliant

Carat

1 ct

Customizable

Metal

Customizable

Setting

Solitaire

An independent IGI grading report is included when the selected individual lab-grown center or primary diamond is 0.50 ct or larger.

Detail	In the photos	Customizable
Center diamond	Portuguese Cut Round Brilliant · 7.00 mm · approx. 1.50 ct	1 ct, 1.5 ct, 2 ct, 2.5 ct, 3 ct, 3.5 ct, 4 ct, 4.5 ct
Accent diamonds	None	—
Total diamond weight	Approx. 1.50 ct	Varies with center size
Stone type	Lab Grown Diamond	—
Setting	Four-Prong Open Basket with Twisted Cathedral Shoulders	—
Finish · Occasion	High Polish · Engagement, Anniversary, Bridal	—

At a glance

A Portuguese cut round lab grown diamond engagement ring from Signora Jewels.

An approximately 1.50 ct Portuguese cut round brilliant measuring 7.00 mm is secured in a four-prong open basket with twisted cathedral shoulders.

Made to order in 11 metals: Silver, 10K/14K/18K Gold (Yellow, White and Rose) and Platinum.

Each metal color is shown in the photos. Choose your preferred center diamond weight and metal from the options on this page.

The Portuguese cut displays an intricate arrangement of facets that creates exceptional depth and brilliance. At Signora Jewels, the twisted cathedral shoulders rise gracefully toward the center before joining a four-prong open basket, giving the ring an elegant flowing profile while leaving the diamond completely visible.

The approximately 1.90 mm comfort-fit shank provides a refined balance beneath the 1.50 ct center stone, while the cathedral shoulders naturally draw the eye upward. The approximately 6.80 mm setting height allows light to reach the pavilion through the open gallery, enhancing the layered reflections unique to the Portuguese cut.

Browse our engagement rings, compare diamond shapes in the diamond stone guide, or explore precious metal options in our metal guide.

Design highlights

Portuguese cut round center shown at approximately 1.50 ct
Customizable center diamond from 1 ct to 4.5 ct
Four-prong open basket setting
Twisted cathedral shoulders
Open gallery for enhanced light performance
Comfort-fit shank approximately 1.90 mm wide

The sculpted shoulders create a gentle twist beneath the center instead of relying on accent diamonds for detail. This flowing profile complements the brilliant faceting of the Portuguese cut while keeping the overall design clean and timeless.

Diamond & Ring Details

Specification	Details
Center stone	Portuguese Cut Round Brilliant · 7.00 mm · approx. 1.50 ct (shown)
Accent stones	None
Total weight / count	Approx. 1.50 ct · 1 Diamond
Setting	Four-Prong Open Basket with Twisted Cathedral Shoulders
Center options	1 ct, 1.5 ct, 2 ct, 2.5 ct, 3 ct, 3.5 ct, 4 ct and 4.5 ct
Finish	High Polish

Measurements are approximate. Your selected center diamond weight determines the final proportions of the finished ring.

About Lab Grown Diamonds

The Portuguese cut features a high number of facets that create layered reflections and remarkable visual depth. Every center diamond is F color, VS1 clarity and , selected to complement the elegant proportions of this cathedral solitaire.

Metal, Care & Fit

Available in Silver, 10K, 14K and 18K Yellow, White and Rose Gold, plus Platinum. Clean beneath the open basket and between the twisted shoulders using warm water, mild soap and a soft brush to maintain maximum brilliance and preserve the polished finish.

FAQ

What makes a Portuguese cut unique?
The Portuguese cut features more facets than a traditional round brilliant, creating layered reflections and exceptional visual depth while maintaining a classic round outline.

What is the benefit of the twisted cathedral shoulders?
The twisted shoulders guide the eye naturally toward the center diamond while providing elegant support beneath the basket without adding extra width.

Can this ring be worn with a wedding band?
Yes. The cathedral basket allows many straight wedding bands to sit close, while contoured bands can follow the raised profile more precisely.

Which metal color best complements this design?
White gold and platinum maximize the crisp brilliance of the Portuguese cut, while yellow and rose gold create a warm contrast around the round center diamond.

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