Tourmaline: The Rainbow Gem

## The Most Colorful Gemstone Family No gemstone group displays a wider range of colors than tourmaline. From vivid neon blue-green (Paraiba) to intense pink (rubellite), chrome green, canary yellow, bicolor, and watermelon — tourmaline covers the entire spectrum, sometimes within a single crystal. This diversity makes tourmaline a favorite among collectors and designers alike. The name "tourmaline" derives from the Sinhalese word "turmali," a general term for mixed-color gemstones. For centuries, tourmalines were confused with other gems — green tourmalines were sold as emeralds, pink tourmalines as rubies, and the identification of tourmaline as a distinct mineral group came relatively late in gemological history. ## Tourmaline Chemistry Tourmaline is not a single mineral but a group of boron silicate minerals with a complex general formula. The main gem-quality species include: **Elbaite**: The most important gem species. Named after the island of Elba, elbaite is a lithium-bearing tourmaline responsible for most colored gem tourmaline — pink, green, blue, bicolor, and watermelon. Paraiba tourmaline is a copper-bearing variety of elbaite. **Liddicoatite**: A calcium-lithium tourmaline that produces spectacular color-zoned crystals, often showing concentric rings of color when sliced perpendicular to the crystal axis. Named after GIA president Richard Liddicoat. **Dravite**: A magnesium-rich species, typically brown to dark brown-green. Fine golden-brown dravite from East Africa can be attractive. **Uvite**: Another magnesium-calcium species. Chrome tourmaline — the vivid green variety colored by chromium — is typically uvite or dravite. Color in tourmaline comes from an unusual range of coloring agents: iron (blue, green, black), manganese (pink, red), copper (Paraiba blue-green), chromium and vanadium (chrome green), and complex charge-transfer mechanisms that can produce virtually any color. ## Paraiba Tourmaline: The Market Disruptor In 1989, Heitor Dimas Barbosa discovered vivid blue-green tourmalines in the state of Paraiba, Brazil. The stones displayed a neon, electric quality unlike any tourmaline previously seen — caused by copper (Cu²⁺), an element never before documented as a coloring agent in tourmaline. The impact was immediate and lasting. Fine Paraiba tourmalines quickly reached prices of $10,000–$50,000 per carat, rivaling fine sapphire. The original Brazilian deposit was small and quickly depleted, driving prices higher. In the early 2000s, copper-bearing tourmalines were discovered in Mozambique and Nigeria. These African stones display the same copper-induced neon blue-green color mechanism, though the market distinguishes between Brazilian Paraiba (premium) and African "Paraiba-type" (lower, though still significant, prices). GIA uses the term "Paraiba tourmaline" for copper-bearing elbaite regardless of origin; Gubelin restricts the term to Brazilian material. Top Brazilian Paraiba tourmalines of 3+ carats have sold for over $100,000 per carat at auction. ## Rubellite: The Red Tourmaline Rubellite is the trade name for red to purplish-red tourmaline. Fine rubellite displays a saturated pink-red that can rival ruby in appearance, though at a fraction of the price. The best rubellite shows vivid color without the brownish modifier that plagues much pink-red tourmaline. Important sources include Brazil (Minas Gerais), Nigeria, Mozambique, and Madagascar. The finest rubellite — truly red, not pink — is rarer than commonly assumed and commands $500–$2,000 per carat in sizes above 5 carats. ## Chrome Tourmaline Chrome tourmaline gets its intense green from chromium and vanadium — the same elements that color emerald. The result is a vivid, saturated green that some find comparable to fine emerald but at 1/10th the price. Chrome tourmaline from Tanzania (near Merelani) and Kenya displays the finest color. Chrome tourmaline is typically available in small sizes (under 2 carats). Stones above 3 carats of fine color are genuinely rare. ## Watermelon and Bicolor Tourmaline Tourmaline crystals frequently display color zoning — changes in chemistry during crystal growth produce bands of different colors. When these zones are arranged concentrically (green exterior, pink interior), the result is "watermelon tourmaline" — sliced perpendicular to the crystal axis, it shows a pink center surrounded by green, resembling a watermelon slice. Bicolor tourmalines display two or more colors in a single stone. Pink-green, blue-green, and yellow-green combinations are common. Fine bicolors with sharp, vivid color boundaries are collector favorites. ## Indicolite: Blue Without Copper Indicolite is non-copper blue tourmaline, colored by iron. The color ranges from greenish-blue to deep blue. Fine indicolite displays a pure blue without excessive green — rarer than it sounds. Most blue tourmaline tends toward teal or greenish-blue. Indicolite is commonly confused with Paraiba tourmaline by inexperienced buyers. The distinction is chemical (copper vs. iron) and visual (Paraiba displays a neon quality that indicolite lacks). ## Buying and Evaluating Tourmaline ### Color As with all colored stones, color is paramount. Key considerations: - Vivid saturation is valued over pale or dark material - Brownish modifiers significantly reduce value (common in green and pink tourmaline) - Pleochroism is strong in tourmaline — different colors visible from different angles. Cutters orient stones to show the best face-up color. ### Clarity Tourmaline clarity varies by variety: - Green and blue tourmaline: eye-clean is standard and expected - Rubellite: inclusions are more common and more tolerated (similar to ruby/emerald) - Paraiba: even more included material is accepted due to extreme rarity ### Cut Tourmaline crystals are elongated prisms, which is why many tourmalines are cut as emerald cuts or long ovals. The cutter must manage pleochroism by orienting the table to show the most attractive color. Deep, narrow stones may appear too dark — a common problem with tourmaline cutting. ### Treatments Heat treatment is common in tourmaline, particularly for pink and red varieties. Heating can lighten overly dark stones and improve color saturation. Irradiation can intensify color in some varieties. Both treatments are stable and considered standard. Disclosure is required. Paraiba tourmaline is routinely heated to improve color. Unheated Paraiba of fine color is extremely rare and commands additional premiums.