The Solitaire Engagement Ring — Why It Remains the Classic Choice in 2026

Short answer: A solitaire is an engagement ring set with a single diamond, with no side stones. The classic form is a round brilliant cut in a gold or platinum band. At Karat Bulgaria, most solitaires today are set with lab-grown diamonds with IGI certificates — the same stone, the same craftsmanship, at a more accessible price. A 1 ct D/VVS1 round solitaire at Karat: around €1,074.

What is a solitaire engagement ring

The solitaire is the purest form of engagement ring. The name comes from the French solitaire — "alone, single" — and means exactly that: one diamond, set in a band, with no surrounding or side stones.

Why it has become the classic. Since 1886, when Tiffany & Co. introduced the six-prong setting, this shape has become the visual standard for a marriage proposal. At Karat Bulgaria we observe that 8 out of 10 engagement rings in 2026 are solitaires — and over half are set with lab-grown diamonds.

For the differences between lab-grown and mined diamonds, see our complete lab-grown diamond guide.

Diamond cuts for a solitaire — why round wins

The round brilliant cut is the standard for solitaires for one reason: it returns more light to the eye than any other cut. Developed by Marcel Tolkowsky in 1919, it has 57 or 58 facets and produces maximum brilliance.

Other cuts offered for solitaires at Karat:

• Oval — elegant, visually elongates the finger, roughly 10% more accessible than round at the same carat weight
• Pear — asymmetric, stylistically bolder, flattering on a long finger
• Marquise — pointed at both ends, vintage feel
• Emerald — step-cut, luxurious Art Deco style
• Princess — square, modern geometry

For a classic solitaire worn for 30+ years, Karat's recommendation is round brilliant. It doesn't go out of style, resells more easily if the need ever arises, and is always the safe choice.

Why a lab-grown diamond for a solitaire

A lab-grown diamond is the same mineral as a mined one — pure carbon, hardness 10 on the Mohs scale — but produced in a controlled environment rather than in the Earth's mantle. It is certified by IGI or GIA using identical methodology. In 2018, the U.S. FTC removed the word "natural" from the definition of "diamond." Both types are sold as "diamond" — because they are.

What the buyer gains with a lab-grown solitaire:

• A larger, cleaner stone for the same budget. €3,800 buys a 1 ct mined diamond in the middle range; the same sum buys 2 ct in D/VVS1 clarity in lab-grown.
• The same visual characteristics. Under a loupe, the difference is invisible — only the certificate distinguishes the two stones.
• Full traceability. A lab-grown diamond has a known place and date of production — something impossible with mined diamonds.
• The lab-grown standard has won the market. Modern boutiques worldwide have shifted to lab-grown. This is not an alternative to mined — it is the new standard.

Indicative prices for round brilliant cut, May 2026. Solitaires in platinum bands are approximately 15–20% higher than in 14k gold bands.

For comparison: a mined 1 ct D/VVS1 in the same class is around €3,800. The same stone by gemological specification, approximately 3.5× the price.

What size stone to choose

The most common mistake observed at Karat Bulgaria: clients choosing a stone that is too small for a long, slim hand. 0.5 ct looks beautiful in photos but can visually "disappear" on longer fingers. For reference:

• 0.5 ct ≈ 5.1 mm diameter
• 1.0 ct ≈ 6.4 mm
• 1.5 ct ≈ 7.4 mm
• 2.0 ct ≈ 8.1 mm

Above 1 ct is the sweet spot for a solitaire on a medium-width hand. Our guide on how to measure ring size covers how to do it without your partner knowing.

The IGI certificate — what to ask for

Never buy a solitaire without an IGI or GIA certificate. The certificate documents the 4 Cs — carat (weight), color, clarity, cut — plus the laser inscription of the report number on the diamond's girdle (visible under a 10× loupe).

At Karat, our specialists review every certificate with the client before finalizing the purchase. This step takes 10 minutes and protects your decision from a costly mistake. Here is how to read an IGI certificate step by step.

The Karat approach to choosing a solitaire

When a client visits the Karat boutique for a solitaire, our specialists always begin with two questions: what does the future wearer's hand look like, and what style does she wear every day. Not the price. Not the carats. These two questions first.

The reason is simple: a solitaire is jewelry for every day for the next 30+ years. The classic round brilliant cut in 14k yellow or white gold with a 1 ct D/VVS1 lab-grown diamond is the choice the Karat team has seen prove most enduring. Over the past two years, 80% of the engagement rings made in our workshop are exactly this combination.

Karat Bulgaria's recommendation is not "buy the biggest stone the budget allows." It is: choose the right size for her hand with the right certificate, and let style say the rest.

What to remember

The solitaire is the classic because it works — one diamond, one cut, one story that lasts for decades. With a lab-grown diamond today the buyer gets the same stone as a mined one, with the same IGI certificate, at roughly one-third of the price. Round brilliant remains the safe choice for long-term wear. The size should match the hand, not the budget. And always — require a certificate.