Portuguese-Cut Vivid Blue Diamond Martini Studs

Most stud earrings are content to be stud earrings. They show up, they hold a diamond, they do not aspire to PhD-level diamond cutting or rare fancy color. The Round Portuguese Cut Vivid Blue Diamond Martini Stud is a different proposition entirely — a small earring with a genuinely serious resume — and I want to walk you through it because I think it's one of the most interesting pieces in our case.

The Portuguese Cut: A Quick Crash Course

The Portuguese cut is to the modern brilliant cut what a hand-stitched suit is to a perfectly nice off-the-rack jacket. It exists. Both have buttons. They are, however, not the same garment.

Where a standard round brilliant has 57 or 58 facets, a true Portuguese cut has up to 161. Yes — one hundred and sixty-one. The cutter adds extra rows of facets to both the crown (top) and the pavilion (bottom), which creates a starburst pattern of internal reflections that no other round cut produces. The light bounces a dozen extra times before it leaves the stone, and the result is a fire — the rainbow flashes a diamond throws — that is genuinely distinctive at any size.

The cut was developed in Portugal in the early-to-mid 20th century (the actual origin story is debated; my favorite version credits a Lisbon cutter named Aristides Domínguez) and has remained a slightly cult-status cut ever since. It costs more, it takes longer, it wastes more rough diamond, and most cutters won't bother with it. The ones who do are show-offs. Bless them.

And Now: Vivid Blue

Layered on top of the Portuguese cut: a fancy vivid blue color. As discussed in the Izzy essay, fancy color diamonds are graded on a separate scale from white diamonds. "Fancy Vivid Blue" is the most saturated color grade in the blue category, more vivid than Fancy Intense and significantly more so than Fancy Light.

Natural blue diamonds are extraordinarily rare — they get their color from trace boron impurities, and only a tiny percentage of mined diamonds have any blue at all. The Hope Diamond is a Fancy Dark Grayish Blue. The Oppenheimer Blue, sold at Christie's in 2016 for $57 million, is Fancy Vivid Blue. The vivid blues in our 1.5-carat-total-weight pair are smaller, of course, but they sit firmly in the same color category — and the Portuguese cut amplifies the blue spectacularly. The extra facets multiply the color flashes; the stone almost shimmers between sapphire-blue and a more electric, almost-aquamarine ice.

Katura's Approach

Why a martini setting and not something more elaborate? Because the diamonds are doing the heavy lifting. A halo or a fancy gallery would have buried the cut. The martini's three slim prongs angle the stones up and away from the ear, exposing nearly the entire pavilion to light, which is exactly what a Portuguese cut needs to throw its full fire. Minimal metal. Maximum performance.

White gold for the same reason — it's the Switzerland of metals, neither warming nor cooling, just letting the blue read as blue.

How to Wear Stones This Specific

One general rule for fancy color studs of any kind: let them be the only colored thing on you. A vivid blue earring next to a sapphire ring next to a turquoise scarf is a chord with too many notes. Wear these with white, navy, charcoal, cream, ivory, soft gray. Let the blue be the point.

And do, please, wear them in daylight at least sometimes. Fancy color diamonds — especially Portuguese-cut ones — perform best in mixed light. Direct sunlight on a Portuguese cut is something close to a small private fireworks show. You're allowed to look at your own ear in a window now and then. I do.

Care, Practical

Same as any diamond stud — soap, water, soft brush, microfiber dry. The Portuguese cut, with its many extra facets, traps a fraction more dust and skin oil than a brilliant cut, so a monthly cleaning will reward you visibly. Annual prong check at the bench. Insurance scheduled on a rider, please.

Who These Are For

The collector. The reader of my essays who has read this far. The woman who already owns a clean white pair and is ready for the same shape with a story underneath. The fancy color enthusiast who wants the cut as well as the color. The person who genuinely enjoys explaining "actually, the Portuguese cut has 161 facets" at a dinner party — and you know who you are, and we love you.

Wear them well, friends. May your ears throw fireworks.

— Katura

Shop the look

Round Portuguese Cut Vivid Blue Fancy Diamond & White Gold Martini Stud Earrings

$2,500 · From the Katura studio

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