How to choose a solitaire: the diams.com guide

A solitaire is a ring that carries a central diamond, held by prongs or by a setting designed around it. Nothing distracts the eye: the stone is the jewel. The choice runs along two axes: the setting and the diamond. Every decision can be read on the laboratory report or on the model's page.

This guide follows the order diams.com has applied to its own selection since 2004: cut quality above all, color and clarity at the level where the eye stops seeing a difference, then weight. The basics are explained in the guide to the diamond's 4 criteria; here, the point is to rank them for a solitaire.

1. The diamond: the four criteria in a useful order

Cut comes first

Cut means the shape of the stone and the quality of its execution: proportions, symmetry of the facets, polish. It governs how light enters the diamond, travels through it and leaves it, hence its brilliance, fire and scintillation. Two stones of the same weight, color and clarity can look very different for this reason alone. For a round brilliant, GIA grades cut on five levels, from Excellent to Poor; diams.com keeps Excellent and Very Good, with polish and symmetry at the same level. This is the criterion not to compromise on: a well-cut diamond looks larger and livelier than a heavier stone with poor proportions.

Carat, weight and its price

The carat is a unit of mass: 0.2 gram. For a round brilliant of standard depth, the diameter follows: about 5.1 mm at 0.50 ct, 6.4 mm at 1 ct, 8.1 mm at 2 ct. The price is not proportional to weight: it jumps at the round weights, 0.50, 1.00, 1.50 and 2.00 ct, where demand concentrates.

Color, read together with the metal

The GIA scale runs from D, the most colorless, to Z. D, E and F are called colorless; from G to J, the tint is only perceptible by comparison with a master stone, face down on a white background. Set and worn, a G or H stone looks white. The metal matters: white gold and platinum extend the whiteness of D to G grades; yellow or rose gold warms the stone and makes a slight tint, from H to J, practically invisible.

Clarity, as far as the eye can see

Clarity grades are determined with a 10x loupe: FL and IF, without inclusions, then VVS1 and VVS2, VS1 and VS2, SI1 and SI2, and finally I1 to I3. For a solitaire, whose table is fully exposed, diams.com recommends SI1, VS2, or better: at these grades nothing is visible to the naked eye.

2. The GIA report, to be read before buying

Every diamond offered by diams.com comes with its GIA report, from the independent laboratory founded in 1931 and the market's reference. The report gives shape and measurements, weight, color, clarity, cut grade for the round brilliant, polish, symmetry and fluorescence, with an inclusion plot on the Diamond Grading Report. The report number, usually laser-inscribed on the girdle, can be checked online on the GIA website. For fluorescence, diams.com prefers None: strong fluorescence can give a milky look. The diams.com search engine shows the price of 500,000 GIA-certified diamonds, each with its report.

3. The setting: four prongs, six prongs, or a design

Four prongs hold the stone with a minimum of metal: more of the diamond shows, the outline looks slightly square, the look is pared down. Six prongs draw a rounder outline and hold the stone at six points. Between the two there is no rule, only the eye. diams.com also offers designed settings, Blanche-Neige with pavé shoulders, Océan and its curves, Pyramide, Yin Yang, Lune, each in 0.50, 1 or 1.50 ct depending on the model. All are made to order in Lausanne.

4. The metal: 750 gold or 950 platinum

The settings come in white, yellow or rose 750 gold, that is 18 karat, and in 950 platinum. None is superior in itself. Platinum, denser, is the heaviest on the finger and keeps its color without treatment; white gold is rhodium-plated; yellow and rose gold warm the stone.

5. Ring size

The diams.com ring size guide explains how to measure a finger or an existing ring. For a surprise, a ring already worn on the right finger is enough. In most cases, resizing remains possible afterwards, respecting the proportions and comfort of the band.

6. The budget: where to put the effort

The order of priorities follows from the above. Cut quality is not negotiable. An F or H color grade and a VS1 clarity, or an SI1, are enough, and more if your budget allows. Orders of magnitude of prices, by weight and quality, recorded in our search engine: our guide Diamond prices.

7. Ordering, receiving, caring

Each ring is made to order in Lausanne; the indicative lead time is shown on the model's page. Delivery is free in Switzerland, by insured transport and handed over against signature; diams.com also delivers abroad. The jewelry is guaranteed for two years. The diamonds come from legal sources that comply with the Kimberley Process. For care, gentle cleaning in lukewarm water with mild soap and a soft brush is enough; the prongs should be checked from time to time, and a stone that moves means the ring must no longer be worn and should be sent in for inspection. Advice by appointment in Lausanne.

Further reading: Le diamant, Book IV, chapters 2 and 3, on gemmologue.ch (in French).

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