igneous

Granite fragment

Granite

Hardness: 6-7 (Mohs scale), Color: pinkish-gray with dark flecks, Luster: Vitreous to dull, Crystal structure: Phaneritic (coarsegrained), Cleavage: None (fractures), Specific gravity: 2.65-2.75

Identified May 26, 2026More igneous →

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Physical properties

Hardness: 6-7 (Mohs scale), Color: pinkish-gray with dark flecks, Luster: Vitreous to dull, Crystal structure: Phaneritic (coarsegrained), Cleavage: None (fractures), Specific gravity: 2.65-2.75

Formation & geological history

Formed from the slow crystallization of magma below Earth's surface. Primarily found in continental crust and can be billions of years old.

Uses & applications

Commonly used in construction, countertops, monuments, and as crushed stone for road base.

Geological facts

Granite is the most common igneous rock found on Earth's continents and makes up the core of many mountain ranges.

Field identification & locations

Identify by its interlocking crystalline texture containing quartz, feldspar, and mica. Commonly found in mountainous regions or as landscaping gravel.

Other igneous specimens

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous