Rock Identifier
Green tourmaline (likely elbaite) (Tourmaline-group cyclosilicate; likely elbaite, Na(Li,Al)3Al6(BO3)3Si6O18(OH)4) — gemstone
gemstone

Green tourmaline (likely elbaite)

Tourmaline-group cyclosilicate; likely elbaite, Na(Li,Al)3Al6(BO3)3Si6O18(OH)4

AI-generated identification · may be incorrect

Vivid green, translucent to opaque, with strong vitreous luster and apparent prismatic/trigonal crystals; commonly has uneven fractures and black matrix/inclusions. Hardness 7–7.5 Mohs; no prominent cleavage; specific gravity about 3.0–3.3.

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Physical properties

Vivid green, translucent to opaque, with strong vitreous luster and apparent prismatic/trigonal crystals; commonly has uneven fractures and black matrix/inclusions. Hardness 7–7.5 Mohs; no prominent cleavage; specific gravity about 3.0–3.3.

Formation & geological history

Forms in lithium-rich granitic pegmatites and hydrothermal veins, commonly with quartz, feldspar, mica, and black schorl. Crystals formed during late-stage pegmatite cooling, generally in Precambrian to younger continental crust.

Uses & applications

Gem-quality material is cut for jewelry; lower-grade pieces are collectors’ specimens and sources of tourmaline for scientific and ornamental use. Rough fragments of this quality typically have modest value.

Geological facts

The green color can result from iron, chromium, or vanadium; color zoning is common. Black areas are likely schorl tourmaline or attached matrix, though visual identification cannot exclude fluorite, beryl, or dyed material.

Field identification & locations

The apparent prismatic crystal habit and green color support tourmaline, but testing is needed: tourmaline is harder than glass, shows no cleavage, and may become electrically charged when warmed or rubbed. Zambia’s pegmatite regions make this plausible near 11.2°S, 24.2°E, though laboratory confirmation is advisable.