mineral

Bicolor or Tricolor Tourmaline

Elbaite (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4)

Hardness: 7-7.5 (Mohs scale); Color: Pink-purple to green-yellow; Luster: Vitreous; Crystal Structure: Trigonal (often long prismatic with striations); Cleavage: Indistinct; Specific Gravity: 3.0-3.26

Hardness: 7-7
Color: Pink-purple to green-yellow
Luster: Vitreous

Identified July 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed in granitic pegmatites through hydrothermal processes. The color zoning occurs when the chemical environment (trace elements like manganese, iron, or lithium) changes during the crystal's slow growth period.

Uses & applications

Used primarily as a gemstone for jewelry (rings, pendants) and as a prized mineral specimen for collectors.

Geological facts

Tourmaline is both pyroelectric and piezoelectric, meaning it can generate an electrical charge when heated or squeezed. This specific color distribution is often called 'Watermelon Tourmaline' if it has a pink core and green rim, but 'Polychrome' or 'Bicolor' when zoned along the length.

Field identification & locations

Identified in the field by its long, pencil-like prismatic crystal habit, vertical striations along the length, and its characteristic triangular cross-section. Found in Brazil, Afghanistan, and Maine/California in the US.

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Mineral

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Mineral/Rock

Granite

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