Mineral
Elbaíta
Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ · Silicatos (Ciclosilicatos)
Elbaite is the lithium-rich member of the tourmaline group, a complex borosilicate of lithium, sodium and aluminium within the cyclosilicates.
It forms elongated prismatic crystals with longitudinal striation parallel to the long axis. It displays a wide colour range. Green hues are commonly due to traces of iron or chromium. Pink colours are associated with manganese. The green variety is known as verdelite.
It typically occurs in granitic pegmatites. At Stak Nala, bicolour terminations with "green caps" over darker bodies are common, produced by late-stage chemical changes. Lemon-green tones are typical in those pegmatites. Pale green elbaite is typical of Brazilian granitic pegmatites. Afghan pegmatites characteristically yield pink colours.
Etymology
From the toponym "Elba", the Italian island where elbaite was originally identified, and "verdelite" for its characteristic green colour.
Specimens in the collection (7)
- Elbaíta (Verdelita) — Minas Gerais, Sudeste, Brasil № 0154
- Elbaíta (Green Cap) — Stak Nala, Skardu District, Baltistán, Gilgit-Baltistán, Pakistán № 0259
- Elbaíta (Verdelita) — Otjua Mine, Karibib, Erongo, Erongo Region, Namibia № 0316
- Elbaíta (Verdelita) — Minas Gerais, Sudeste, Brasil № 0348
- Elbaíta (Verdelita) — Stak Nala, Shigar Valley, Skardu District, Gilgit-Baltistán, Pakistán № 0349
- Elbaíta (Rubelita) — Laghman, Hindu Kush, Laghman, Afganistán № 0351
- Elbaíta (Verdelita) — Minas Gerais, Sudeste, Brasil № 0359