gemstone

Rough green tourmaline crystal

Elbaite tourmaline, complex sodium-lithium aluminum borosilicate; approximate formula Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

Dark olive-green, translucent to opaque crystal with a vitreous luster and likely longitudinal striations; tourmaline is trigonal and commonly has no obvious cleavage. Hardness is 7–7.5 Mohs and specific gravity about 3.0–3.3.

Identified August 18, 2026More gemstone →

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At a glance

Common name: Rough green tourmaline crystal
Scientific name: Elbaite tourmaline, complex sodium-lithium aluminum borosilicate; approximate formula Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
Category: gemstone
Identified: August 18, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a small opaque rough specimen; $50–$500+ if translucent, well-formed, and attractive, with fine facetable material worth substantially more.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Typically forms in lithium-rich granite pegmatites as late-stage hydrothermal crystals, generally in Precambrian to younger continental crust. The photograph is insufficient to determine its geological age or confirm species-level identification.

Uses & applications

Gem-quality green tourmaline is cut for jewelry; lower-grade material is collected, cabbed, or used decoratively. Industrial tourmaline has limited use, though its piezoelectric and pyroelectric properties are notable.

Geological facts

Tourmaline crystals can develop strongly striated prismatic faces and become electrically charged when heated or rubbed. Green color may also reflect chromium or vanadium in some varieties.

Field identification & locations

Look for a prismatic, striated crystal, triangular or rounded cross-section, glassy luster, and resistance to scratching by steel. Common sources include Brazil, Afghanistan, Pakistan, Namibia, Nigeria, Madagascar, and the United States; testing by refractive index or Raman analysis is needed for certainty.