igneous
Black Granite (likely Gabbro or Dolerite)
Phaneritic Mafic Igneous Rock (plagioclase and pyroxene)
Hardness: 6-7 Mohs; Color: dark grey to black with light grey/white mottling; Luster: vitreous to dull; Crystal structure: phaneritic (visible grains); Specific gravity: 2.7-3.3
- Hardness
- 6-7 Mohs
- Color
- dark grey to black with light grey/white mottling
- Luster
- vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 Mohs; Color: dark grey to black with light grey/white mottling; Luster: vitreous to dull; Crystal structure: phaneritic (visible grains); Specific gravity: 2.7-3.3
Formation & geological history
Formed by the slow cooling of magnesium and iron-rich magma beneath the Earth's surface. Common in Precambrian shield areas like the Eastern Ghats in India.
Uses & applications
Extensively used in construction for countertops, monuments, flooring, and decorative tiles due to its hardness and aesthetic appeal.
Geological facts
The region near Guntur and Andhra Pradesh is world-famous for its high-quality 'Black Galaxy' and other varieties of black granite. This sample shows a classic interlocking crystalline texture.
Field identification & locations
Identified by its salt-and-pepper look, absence of quartz streaks, and extreme hardness. It is very common in the peninsular plateau of India.
