mineral
Chrysoberyl (Cyclic Twin)
Beryllium Aluminum Oxide (BeAl2O4)
AI-generated identification · may be incorrectHardness: 8.5 (Mohs scale); Color: Yellowish-green to brownish-green; Luster: Vitreous; Crystal Structure: Orthorhombic (often forming pseudo-hexagonal cyclic twins); Cleavage: Distinct {011}; Specific Gravity: 3.5–3.8
- Hardness
- 8
- Color
- Yellowish-green to brownish-green
- Luster
- Vitreous
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Physical properties
Hardness: 8.5 (Mohs scale); Color: Yellowish-green to brownish-green; Luster: Vitreous; Crystal Structure: Orthorhombic (often forming pseudo-hexagonal cyclic twins); Cleavage: Distinct {011}; Specific Gravity: 3.5–3.8
Formation & geological history
Formed in granitic pegmatites and mica schists, often through metamorphic processes where beryllium is present. Commonly found in alluvial deposits due to its high hardness and resistance to weathering.
Uses & applications
Primarily used as a gemstone (including varieties like Alexandrite and Cat's Eye) and highly valued by mineral collectors for its unique twinning habits.
Geological facts
This specimen displays a famous 'V-twin' or 'heart-shaped' cyclic twin. Chrysoberyl is the third-hardest natural gemstone after diamond and sapphire. The variety 'Alexandrite' is famous for its color-change property under different lighting.
Field identification & locations
Identify in the field by its extreme hardness, vitreous luster, and characteristic trilling or V-shaped twinning. Major locations include Brazil, Sri Lanka, Madagascar, and Russia (Urals).
