Aerugite is a rare nickel arsenate mineral, historically described from European localities, and notable for its vivid green coloration. It is considered a secondary mineral, forming in the oxidation zones of nickel-arsenic deposits.
đ Origins and Naming
- Name Origin: From Latin aerugo (âverdigrisâ or âgreen rustâ), referencing its bright green color.
- Discovery: First described in the 19th century.
- Type Locality: Saxony, Germany.
đŹ Chemical and Structural Properties
- Formula: Niâ(AsOâ)â(AsOâOH)â¡8HâO
- Mineral Group: Arsenates
- Crystal System: Triclinic
- Color: Bright green to emerald-green
- Habit: Typically occurs as crusts, earthy masses, or fine-grained aggregates rather than well-formed crystals
- Hardness: ~2 on Mohs scale (very soft)
- Specific Gravity: ~4.1â4.2
- Luster: Dull to earthy
- Streak: Green
âď¸ Geological Occurrence
Aerugite is a secondary mineral, forming through the alteration of nickel arsenides and sulfides in the presence of oxygen and water.
- Associated Minerals: Annabergite (Ni arsenate), erythrite (Co arsenate), and other secondary arsenates.
- Localities:
- Saxony, Germany (classic locality)
- Cornwall, England
- Other European nickel-arsenic deposits
đ Scientific and Collector Significance
- Mineralogical Rarity: Aerugite is extremely rare and often poorly crystallized, making it more of a scientific curiosity than a collectorâs showpiece.
- Research Value: Provides insight into the geochemistry of nickel and arsenic in oxidized environments.
- Collector Appeal: Its vivid green color is attractive, but specimens are usually small and earthy.
â ď¸ Safety Considerations
Aerugite contains arsenic, making it potentially toxic. Handling requires careâavoid inhaling dust or ingesting particles, and wash hands after contact.
⨠Conclusion
Aerugite is a rare nickel arsenate mineral, valued for its bright green color and scientific significance in understanding secondary mineral formation in arsenic-rich deposits. Though not a major collectorâs mineral due to its rarity and earthy habit, it remains an important piece of mineralogical history.
In short: Aerugite is a rare, bright green nickel arsenate from Saxony, Germany, formed in oxidized nickel-arsenic deposits.
