igneous

Granite

Phaneritic Igneous Rock (Granite)

Hardness: 6-7 on Mohs scale; Color: Mottled gray with specs of black and white; Luster: Dull to vitreous; Crystal structure: Phaneritic (coarse-grained) crystals of quartz, feldspar, and mica; Specific gravity: 2.63 - 2.75.

Hardness: 6-7 on Mohs scale
Color: Mottled gray with specs of black and white
Luster: Dull to vitreous

Identified February 19, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow cooling of silica-rich magma deep underground (plutonic). Found in continental crust, often appearing in mountain ranges or cratons. Ages can span from billions of years (Archean) to more recent tectonic events.

Uses & applications

Extensively used in construction as dimension stone, countertops, floor tiles, and aggregate for roads. Occasionally used for monuments or small decorative carvings.

Geological facts

Granite makes up the bulk of the Earth's continental crust. It is one of the hardest natural stones commonly found, and its interlocking crystal structure makes it incredibly resistant to weathering.

Field identification & locations

Identify by its 'salt and pepper' appearance and visible, interlocking crystals that are large enough to see without a lens. Often found in riverbeds or mountainous regions. Collectors look for unique color variants or large inclusions.

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