igneous
Granite with Tourmaline
Felsic intrusive igneous rock containing schorl (tourmaline)
Hardness: 6-7 on Mohs scale; Color: whitish-gray matrix with black prismatic crystals; Luster: vitreous to sub-vitreous; Crystal structure: hexagonal (tourmaline) and granular phaneritic (matrix); Specific gravity: 2.6-2.8
- Hardness
- 6-7 on Mohs scale
- Color
- whitish-gray matrix with black prismatic crystals
- Luster
- vitreous to sub-vitreous
Identified More igneous →
Explore Granite with Tourmaline in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale; Color: whitish-gray matrix with black prismatic crystals; Luster: vitreous to sub-vitreous; Crystal structure: hexagonal (tourmaline) and granular phaneritic (matrix); Specific gravity: 2.6-2.8
Formation & geological history
Formed by the slow crystallization of magma beneath the Earth's surface, often associated with pegmatitic or late-stage magmatic fluids rich in boron.
Uses & applications
Used in construction, architectural facings, monuments, and as decorative stone or mineral specimens for collectors.
Geological facts
The black crystals visible in the rock are tourmaline, likely the schorl variety, which forms when boron-rich fluids interact with cooling granitic magma.
Field identification & locations
Commonly found in continental shields and mountain-building regions globally; the Arabian Shield region contains extensive basement rocks including granitic intrusions.
