igneous
Granitoid (Granite/Gneiss mix)
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale; Color: Mottled pink, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Composition: Quartz, Potassium Feldspar, and Biotite/Amphibole.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled pink, white, and black
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled pink, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Composition: Quartz, Potassium Feldspar, and Biotite/Amphibole.
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specific specimen shows signs of water-wearing, likely a river or beach pebble, and may exhibit slight foliation indicative of metamorphic transition.
Uses & applications
Used extensively in construction (granite countertops, tiles), as crushed stone for road base, and as decorative landscaping gravel.
Geological facts
Granite is the primary component of Earth's continental crust. Over 40% of the rock's volume is typically mineralized quartz and feldspar, making it extremely durable against weathering.
Field identification & locations
Identifiable by its 'salt and pepper' appearance with pinkish hues from orthoclase feldspar. Common in glacial tills, riverbeds, and mountainous regions across all continents.
