Tourmaline

Tourmaline is a complex borosilicate mineral group prized by collectors and gemologists alike for its extraordinary range of colors, often within a single crystal. Chemically it belongs to the cyclosilicates, with boron combined with aluminum, iron, magnesium, sodium, or lithium; the main species collectors seek include elbaite, schorl, dravite, uvite, and liddicoatite. Color zoning, from watermelon pink-green crystals to deep indicolite blue, comes from substitutions of manganese, iron, and chromium within the structure.

The species was first described from the Rosina pegmatite near San Piero in Campo on the island of Elba, Italy, still famous for its historic "Moor's Head" bicolor crystals. Other classic elbaite localities include Mount Mica and the Dunton Quarry in Maine, the Himalaya Mine in California, Stak Nala in Pakistan, Mogok in Myanmar, the Malkhan pegmatite in Siberia, and Madagascar's Sahatany field. The most exceptional specimens, however, are the copper-bearing Paraíba tourmalines from Brazil, with comparable neon-blue material later found in Nigeria and Mozambique, alongside vivid chrome-rich green tourmaline from Tanzania.

Collectors value tourmaline for its unmatched color diversity, sharp striated prismatic habit, and the rarity of gem-clarity crystals from historic pegmatite localities, making fine specimens both scientifically important and highly decorative.