Tourmaline is a family of precious stones belonging to the complex silicate group. It occurs naturally in an exceptionally wide range of colours. With a hardness of 7–7.5 on the Mohs scale, it offers good resistance to everyday wear. Tourmaline grows in rocks known as pegmatites — formed by the crystallisation of magmas rich in rare elements. It is one of the very few gemstone families to offer such a breadth of colour varieties.

The tourmaline family includes more than 30 recognised varieties, the best-known of which carry specific names. Paraíba tourmaline refers to neon blue-green stones coloured by copper. Rubellite covers shades from vivid pink to deep red. Indicolite encompasses blue tourmalines. Verdelite designates the green varieties. Chrome tourmaline displays a rare, intense and deep green. Dravite presents brown or yellow tones. Schorl refers to opaque black varieties.

These three names refer to three distinct tourmaline varieties. Rubellite covers pink-to-red tourmalines, coloured by manganese. Indicolite groups the blue tourmalines, coloured by iron. Paraíba tourmaline displays a characteristic neon blue-green, owing its colour to copper. This variety was discovered in Brazil in the 1980s. Paraíba remains by far the most valuable of all tourmalines, with prices exceeding €20,000 per carat.

Tourmalines are sourced primarily from four regions of the world. Brazil (Minas Gerais) has been the historic benchmark since the 18th century. Madagascar has established itself as the second largest source since the 1990s. Afghanistan (Nuristan) yields exceptional stones, particularly indicolites and rubellites. Africa (Nigeria, Mozambique, Namibia, Tanzania) rounds out the supply with a wide range of colours. Russia (the Urals) and the United States (California) also have long-standing historic production.

The price of a tourmaline varies considerably depending on variety and quality. For common varieties (green, light pink), expect €100 to €500 per carat. Gem-quality rubellite reaches €1,000 to €3,000 per carat. Well-saturated indicolite trades at €500 to €2,000 per carat. Chrome tourmaline frequently exceeds €2,000 per carat. Paraíba tourmaline sits in a category of its own: €5,000 to €50,000 per carat, depending on the intensity of its neon blue.

Most tourmalines remain untreated at the point of sale. A proportion do, however, undergo low-temperature heating to intensify their colour — a stable, market-accepted treatment. Paraíba tourmalines are often heated to reveal their characteristic neon blue. Deeply saturated rubellites may receive irradiation to enhance their pink. Bonnot Paris favours natural, untreated tourmalines. The independent certificate always specifies any treatment the stone may have received.

Yes, tourmaline is suitable for an engagement ring, with a few considerations. Its hardness of 7–7.5 on the Mohs scale makes it less resistant than sapphire or ruby. A protective setting is advisable for intensive daily wear. That said, tourmaline offers a chromatic diversity unmatched in the gem world, making it possible to find a truly personal and original stone for a marriage proposal. Its infinite palette remains one of its greatest strengths alongside more classical gems.

Tourmaline carries rich and varied symbolism depending on its colour. Rubellite symbolises passion and romantic commitment through its pink-to-red hue. Indicolite evokes serenity, communication and wisdom. Green tourmaline represents balance, healing and prosperity. Black tourmaline (schorl) has traditionally stood for energetic protection. Tourmaline is a customary gift for eighth wedding anniversaries. Its chromatic diversity makes it a stone suited to every occasion.