The Solitaire Defined: A Gemological Perspective on the Classic Single Stone

By: International Institute of Gemology (IIG)

In the world of gemology and jewelry design, few terms are as ubiquitous as “Solitaire.” While the word might conjure images of a card game for some, in our industry, it represents the purest expression of a gemstone’s beauty.

But what exactly defines a solitaire, and why has it remained the gold standard for engagement rings and fine jewelry for over a century?

Let’s explore the technical definition, historical significance, and the various shapes that define this iconic jewelry style.

What Is a Solitaire?

Strictly speaking, a solitaire refers to any piece of jewelry that is set with a single diamond or gemstone. While the term is most frequently associated with engagement rings, it applies equally to pendants, earrings, and men’s jewelry, provided they feature one singular, standalone stone.

The beauty of a solitaire lies in its lack of distraction. Without side stones or intricate halos to divert attention, the focus remains entirely on the cut, clarity, and color of the center gemstone—qualities that gemologists value most.

A Common Misconception: Solitaire vs. “Monolithic”

At IIG, we often encounter varied terminology used by jewelry enthusiasts. One recurring misconception is the use of the word “monolithic” to describe single-stone rings.

Derived from mono (one) and lithic (stone), the term may appear linguistically logical. However, it is gemologically incorrect. A monolith traditionally refers to a large, singular stone structure such as a pillar or monument.

In professional gemological practice, the correct and universally accepted term for a single-stone jewel is solitaire.

The Evolution of an Icon

How did the solitaire become the definitive symbol of love and commitment? Its dominance can be traced to two pivotal historical developments:

1. The Tiffany Setting

The iconic six-prong Tiffany setting revolutionized diamond mounting. By elevating the diamond above the band rather than embedding it within metal, light could enter from all directions—maximizing brilliance and fire. This innovation established the modern solitaire as we know it today.

2. “Diamonds Are Forever”

The emotional significance of the solitaire was firmly cemented by De Beers’ legendary marketing campaign. Copywriter Frances Gerety’s slogan, “Diamonds are Forever,” along with the introduction of the “salary guideline,” permanently linked the solitaire diamond with eternal romance and commitment.

Beyond the Round Brilliant: Understanding Solitaire Shapes

While the solitaire setting is minimal, the shape of the gemstone allows for personal expression. Below are the most popular solitaire cuts in today’s market:

• Round Brilliant:
  The undisputed leader. With 57 facets engineered for maximum light return, it is the most brilliant and most widely chosen solitaire cut. Learn more about diamond fundamentals to understand cut quality.
  
  
• Princess Cut:
  The second most popular shape. A modern square cut with over 70 facets, known for intense sparkle. 
• Emerald Cut:
  A rectangular step-cut prized for its elegant “hall of mirrors” effect rather than sheer brilliance.
  
  
• Oval Cut:
  An elongated variation of the round brilliant that can visually lengthen and slim the finger.
  
  
• Marquise Cut:
  A boat-shaped cut with pointed ends that maximizes perceived carat size and offers a regal silhouette. 
• Heart Shape:
  A highly emotive cut—often loved or disliked strongly—commonly chosen for romantic milestones and Valentine’s jewelry. 
• Antique Cuts:
  A resurgence of Old Mine Cuts and other vintage styles is evident today, often reclaimed from heirloom pieces and reset into modern solitaire designs. 

The Versatility of the Solitaire

One of the most practical advantages of the solitaire setting is its adaptability to heirloom jewelry. Because the design focuses entirely on the center stone, it is ideal for remounting inherited diamonds.

Many individuals choose to preserve sentimental family stones by resetting them into contemporary solitaire mounts. This approach maintains emotional value while updating aesthetics—an approach strongly aligned with sustainable and responsible jewelry practices.

Whether strictly classic or modern and tension-set, the solitaire remains a powerful testament to the idea that less truly is more.

Frequently Asked Questions (FAQs)

What defines a solitaire in gemology?

A solitaire is any piece of jewelry featuring a single diamond or gemstone as the focal point, without additional side stones or halos.

Is a solitaire limited to engagement rings?

No. While most commonly associated with engagement rings, solitaires can also be found in pendants, earrings, men’s rings, and other fine jewelry.

Is “monolithic” a correct term for a solitaire ring?

No. While linguistically similar, “monolithic” is not gemologically correct. The correct industry term is solitaire.

Why are round brilliant solitaires the most popular?

Round brilliant diamonds offer maximum brilliance due to their precise faceting, making them the most widely preferred choice for solitaire jewelry.

Can heirloom diamonds be reset into solitaire settings?

Yes. Solitaire settings are ideal for remounting inherited diamonds, preserving sentimental value while updating the design.

Final Thoughts

The solitaire is more than a jewelry style—it is a gemological statement. Rooted in history, refined by craftsmanship, and enduring in symbolism, the solitaire continues to define elegance through simplicity.

At the International Institute of Gemology (IIG), we view the solitaire as the ultimate celebration of a gemstone’s natural beauty—where one stone, expertly cut and thoughtfully set, tells a timeless story.