Field report · 913
What to look for in a tourmaline cabochon
Tourmaline comes in every color of the rainbow. Here's how to grade one — and why cabochons are often a better buy than faceted stones.
Tourmaline is one of the few stones where buying a cabochon is sometimes the smart move, even at high price points. The reason: tourmaline's strong pleochroism (looking different from different angles) and frequent inclusions mean that the highest-quality material is often opaque or translucent, not transparent. A great cabochon shows off the color without forcing it through a faceted geometry that fights the stone's nature.
Start with color
Tourmaline comes in roughly twelve recognized color varieties, each with its own market:
- Indicolite — blue. The deeper the blue, the higher the premium.
- Rubellite — red to pink. Saturated, no orange cast.
- Verdelite / chrome — green. Chrome tourmaline (with chromium impurities) is rare and prized.
- Paraíba — neon blue-green. Originally Brazilian; commercial "Paraíba-type" now also comes from Mozambique and Nigeria. Prices range from premium to extreme.
- Watermelon — pink core, green rim. Cabochons are the best way to show this.
- Bi-color and tri-color — distinct color zones in one crystal.
What makes a great cabochon
For cabochons specifically, you want:
- Even surface polish — tourmaline takes polish well but has hardness that varies along the crystal axis
- Color visible from multiple angles — rotate it in your hand; if one orientation looks dramatically darker, it's not been cut along the optimal axis
- Minimal surface-reaching inclusions — internal veils are fine; cracks that reach the surface can spread
Avoid these common issues
Heated and irradiated tourmaline is common at all price points — usually disclosed as "color enhanced." Synthetic tourmaline is rare in the trade but exists. The most common buyer mistake is paying Paraíba prices for ordinary blue tourmaline that's been marketed as "Paraíba-style" — true Paraíba shows fluorescent neon under daylight, not just under the seller's lamp.