mineral

Bicolor tourmaline crystal

Elbaite tourmaline, Na(Li₁.₅Al₁.₅)Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

Hardness 7–7.5 Mohs; pink-to-green zoning, vitreous luster, trigonal prismatic crystal structure, and indistinct cleavage. The striated prism and strong pleochroism are characteristic of tourmaline.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms in lithium-rich granitic pegmatites through late-stage hydrothermal crystallization, commonly during the Mesozoic or younger. The pink core and green outer zone reflect changing chemistry during crystal growth.

Uses & applications

Used as a gemstone when transparent and well-formed; attractive crystals are prized by collectors. This specimen appears primarily mineral-collector grade rather than jewelry grade.

Geological facts

Pink-and-green elbaite is often called “watermelon tourmaline,” especially when the color zoning is concentric. Tourmaline is strongly piezoelectric and becomes electrically charged when heated or compressed.

Field identification & locations

Identify it by its elongated, longitudinally striated prism, triangular-to-rounded cross-section, and pink/green zoning; quartz lacks these striations and tourmaline’s strong color zoning. Common sources include Minas Gerais, Brazil; Afghanistan; Madagascar; California; and Maine.