Sapphires: beyond royal blue

A rainbow of colors

While blue sapphire remains the most iconic, this gem from the corundum family exists in a stunning palette of colors that surprises even the most seasoned connoisseurs. Soft pink, flamboyant orange, solar yellow, deep green, imperial violet and even the extremely rare padparadscha, whose salmon hue evokes sunsets over Sri Lanka.

Chemically, sapphire is an aluminum oxide (Al2O3), exactly like ruby. Only trace elements — iron and titanium for blue, chromium for pink, iron for yellow — determine the final color of the stone. This kinship with ruby makes corundum one of the most fascinating gem families in the mineral kingdom.

So-called "fancy" (colored) sapphires are increasingly popular among collectors and jewelry designers. The padparadscha sapphire, native to Sri Lanka, remains the most coveted: specimens over 5 carats reach record sums at auction, sometimes exceeding the price of blue sapphires of equivalent quality.

The Kashmir blue sapphire: a living legend

Kashmir sapphires, discovered in 1881 in the heights of the Himalayas at nearly 4,500 meters altitude, are considered the most beautiful in the world. Their velvety blue possesses a unique silky quality, due to microscopic rutile inclusions that diffuse light like a silk veil. This characteristic, called the "velvet effect," is unique to Kashmiri stones and has never been replicated by any other deposit.

A fine-quality Kashmir sapphire is now rarer than a blue diamond of the same size. To own one of these treasures is to hold a fragment of the Himalayas crystallized millions of years ago.

The Kashmir mines, located in the Zanskar valley, are now largely depleted. Nearly all stones available on the market come from old collections or estates. This extreme rarity explains why a 10-carat Kashmir sapphire can reach several million dollars at auction at Christie's or Sotheby's.

Other famous origins

Beyond Kashmir, Sri Lanka (formerly Ceylon) produces sapphires of remarkable brilliance, often in vivid blue tones. Myanmar (formerly Burma) offers stones with deep, saturated blue. Madagascar has become a major source since the 1990s, delivering gems of all colors in qualities sometimes comparable to historical origins.

How to evaluate a sapphire

Like diamonds, sapphires are evaluated by color, clarity, cut and carat weight. However, the hierarchy of criteria differs significantly: color is by far the most determining factor, representing up to 70% of a sapphire's value on its own.

The ideal blue is a saturated, vivid royal blue without being too dark. Gemologists use the term "cornflower blue" to describe the most prized hue. A sapphire that is too dark loses its brilliance, while one that is too light lacks presence and depth.

The heat treatment question

The vast majority of marketed sapphires have undergone heat treatment to improve their color and clarity. This treatment is accepted by the industry and must be declared on the gemological certificate. However, unheated sapphires of excellent color command a significant premium, as they represent nature in its pure state.

Investing in a sapphire

Exceptional quality sapphires constitute a tangible and portable investment. Unlike financial markets, the value of fine colored stones has steadily increased over the past twenty years, driven by growing Asian demand and an increasingly limited supply.

For a successful investment, prioritize unheated stones, certified by recognized laboratories (GRS, Gubelin, SSEF), of at least 3 carats with documented origin. Kashmir, Myanmar and Sri Lanka remain the most sought-after provenances, with increasing premiums for stones accompanied by a complete provenance history.

In 2015, a 35-carat Kashmir sapphire was sold for $7.3 million at Sotheby's — confirming this gem's status as one of the most precious in the world.