Tourmaline

Spanish conquistadors in 16th-century Brazil encountered green tourmaline and mistook it for emerald — this mistake persisted for decades. The name "tourmaline" comes from the Sinhalese word "toramali" (mixed gems), used by Dutch traders in the 17th century for various colored stones from Ceylon (Sri Lanka).

Scientists recognized tourmaline as a distinct mineral species only in the 19th century, when advances in mineralogy and crystallography enabled precise differentiation.

The mines of San Diego County in California were the primary suppliers of tourmaline to the Chinese imperial court in the late 19th and early 20th centuries — Empress Dowager Cixi was a passionate collector of pink tourmaline. When the Qing dynasty fell in 1912, demand abruptly ceased and the mines went bankrupt.

Paraíba tourmaline is the most prestigious tourmaline variety — electrically neon blue or blue-green color due to copper (Cu) and manganese (Mn) content. First discovered in 1989 in the Brazilian state of Paraíba by Heitor Danta Barbose. Today it comes from two sources: Brazilian Paraíba (rarer, higher prices) and Mozambican mines (more abundant, more accessible price). GIA certificates specify Brazilian or Mozambican origin. Both are "Paraíba" by GIA definition (copper content). Brazilian Paraíba commands 10–100× higher prices per carat than emerald.

Rubellite is the red to pink tourmaline variety with intense saturated color. The difference between rubellite and "pink tourmaline": rubellite retains its red color in both daylight and artificial light; plain pink tourmaline becomes grayish under incandescent light.

Indicolite is the blue variety (iron, manganese). Deep blue specimens are prized; rare "Santa Maria blue" tones resemble aquamarine. Blue tourmaline is generally rarer than pink and green.

Verdelite is the green tourmaline variety (iron + chromium). Chrome-tourmaline is intensely green, similar to emerald. Rare specimens from Tanzania and Afghanistan command high prices.

Watermelon tourmaline: The crystal is green outside, pink inside — slicing the crystal lengthwise reveals this pattern. They are exceptionally attractive and prized.

Bi-color tourmaline: Two or more tones in one stone — e.g., yellow-green, pink-green. The cutter must orient the stone so the colors are correctly positioned.

Tourmaline is one of the most diverse gemstones — it occurs in virtually every color. Overall supply is relatively good, but specific varieties are exceptionally rare:
- Paraíba tourmaline (copper-bearing borosilicate tourmaline, neon blue-green) from Brazil — one of the most expensive colored gems; above 1 ct with intense color commands prices comparable to rubies
- Rubellite (intense red): because the color must remain red even under incandescent light (not pink), true rubellite is rare
- Chrome tourmaline from Tanzania and Kenya: intensely green, colored by chromium (like emerald) but with higher clarity

Brazil (Minas Gerais) is the leading source; Africa (Tanzania, Nigeria, Mozambique) is becoming increasingly important.

Tourmaline has a unique property that distinguishes it from most gemstones: it is piezoelectric and pyroelectric — when heated or squeezed, an electric charge develops on its surface. This property was known as early as the 18th century, when Dutch traders called it "asje-trekker" (ash-puller) — the stone attracted ash particles from a pipe when heated near a fire.

Paraíba tourmaline from Brazil, discovered in 1987 after years of digging by Heitor Dias Barbelos on a hillside in the state of Paraíba, has been one of the most expensive colored gems since its discovery. The electric neon color results from copper — a phenomenon unique among tourmalines.

Tourmaline is one of the few stones that grows in multiple colors simultaneously — "watermelon tourmaline" shows a green outer shell and red-pink interior when cut longitudinally, exactly like a watermelon.