Tourmaline Buying Guide: Colour Varieties, Watermelon & Liddicoatite

No other gem species covers as much of the colour spectrum as tourmaline — every hue plus colourless and black — which makes "tourmaline" less a single stone to evaluate and more a family to navigate by variety name.

The colour map

• Rubellite — pink to red, the tourmaline closest in colour to ruby at a fraction of the price.
• Indicolite — blue, ranging from pale to a deep, ink-like tone.
• Chrome tourmaline — vivid green, coloured by chromium and/or vanadium rather than iron, giving it a more saturated green than most ordinary green tourmaline.
• Paraíba — the electric neon blue-green, copper-bearing variety — see our Paraíba tourmaline guide for that stone specifically.
• Watermelon — concentrically zoned, green rind around a pink core, named for the visual resemblance.
• Canary / lemon — bright yellow.
• Achroite — the rare colourless variety, named from the Greek for "without colour."
• Liddicoatite — a distinct, rarer named variety found mainly in Madagascar (with limited occurrence in Sri Lanka and Afghanistan), named for a former GIA president. Often shows dramatic, complex colour zoning and is a genuine collector's find rather than typical stock.

Watermelon zoning is a specific, named phenomenon

Watermelon tourmaline's colour split — green outside, pink inside — is concentric zoning, distinct from the longitudinal bi-colour zoning tourmaline can also show along its length (for example, pink at one end shading to green at the other). Both are real and naturally occurring; they're simply different geometries of the same colour-zoning tendency the species is known for.

Clarity expectations shift by colour

Pink-red tourmaline (rubellite) typically shows more visible inclusions than blue-green tourmaline as a matter of course, not as a sign of a lesser stone — the two colour families simply form under different conditions. Judge clarity against what's typical for that specific colour, not a single universal standard across the whole species.

What to check before buying

• Which named variety, specifically — "tourmaline" alone tells you little; rubellite, indicolite, chrome and Paraíba command very different prices for the same size and clarity.
• Treatment status — heat treatment is common and generally accepted across most tourmaline colours; irradiation appears in some pinks. Either should be disclosed — see our gemstone treatments guide.
• Clarity judged against the right baseline — don't compare a rubellite's clarity directly against an indicolite's.

Related reading

• Paraiba Tourmaline Buying Guide: The Neon Gemstone
• Green Gemstones Guide: Emerald, Peridot, Tsavorite & Tourmaline
• Gemstone Treatments Explained: Heat, Oil, Diffusion & More

Sources: variety names, watermelon/longitudinal zoning and Liddicoatite naming per general trade gemmological reference (GIA gem encyclopedia, Gem-A's published tourmaline buying guide at gem-a.com); clarity-by-colour asymmetry as commonly described in coloured-stone trade commentary.