Rock Identifier
Beryl (Emerald Variety) (Beryllium aluminum silicate (Be3Al2Si6O18)) — mineral
mineral

Beryl (Emerald Variety)

Beryllium aluminum silicate (Be3Al2Si6O18)

Hardness: 7.5-8.0 (Mohs). Color: Pale to deep green (caused by chromium or vanadium). Luster: Vitreous (glassy). Crystal structure: Hexagonal/Prismatic. Cleavage: Indistinct. Specific Gravity: 2.67-2.78.

Hardness
7
Color
Pale to deep green (caused by chromium or vanadium)
Luster
Vitreous (glassy)
Identified More mineral

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Physical properties

Hardness: 7.5-8.0 (Mohs). Color: Pale to deep green (caused by chromium or vanadium). Luster: Vitreous (glassy). Crystal structure: Hexagonal/Prismatic. Cleavage: Indistinct. Specific Gravity: 2.67-2.78.

Formation & geological history

Formed in hydrothermal veins or pegmatites where beryllium-rich fluids interact with chromium or vanadium-rich rocks (like schists or carbonaceous limestones). Geological age varies globally from Proterozoic to Cenozoic.

Uses & applications

High-quality specimens are used in fine jewelry as gemstones. Lower grade or industrial beryl is a source of beryllium metal used in aerospace and electronics.

Geological facts

Green beryl is only considered an 'emerald' if the color is deep enough; lighter specimens are simply called 'green beryl'. The Gachala Emerald (858 carats) is one of the most famous uncut specimens.

Field identification & locations

Identify in the field by its hexagonal crystal habit and extreme hardness (cannot be scratched by quartz). Commonly found in Colombia, Brazil, Ethiopia, and North Carolina (USA). Look for hexagonal prisms in micaceous schist matrices.