metamorphic
Charnockite
Orthopyroxene-bearing granite (Charnockite)
Hardness: 6-7 Mohs; Color: Dark grey to greenish-black; Luster: Vitreous to dull; Crystal structure: Massive/Granular; Specific Gravity: 2.6-2.7
- Hardness
- 6-7 Mohs
- Color
- Dark grey to greenish-black
- Luster
- Vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 6-7 Mohs; Color: Dark grey to greenish-black; Luster: Vitreous to dull; Crystal structure: Massive/Granular; Specific Gravity: 2.6-2.7
Formation & geological history
Formed under high-temperature and high-pressure granulite facies metamorphism of igneous protoliths. The region near Visakhapatnam (17.7°N, 83.3°E) is part of the Eastern Ghats Mobile Belt, famous for Proterozoic charnockite formations approx. 1.0-1.6 billion years old.
Uses & applications
Extensively used as decorative building stone, aggregate for road construction, railway ballast, and in some cases, carved into monuments.
Geological facts
Named after Job Charnock, the founder of Calcutta, whose tomb was built from this rock. It is often called 'Blue Granite' in the commercial trade despite being metamorphic.
Field identification & locations
Identify by its greasy appearance, dark color, and presence of hypersthene. Common in the Eastern Ghats of India and Southern India. While the user's text on screen mentions 'Fusion Crust,' this specimen lacks the flow lines and regmaglypts of a true meteorite and matches regional bedrock.
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