igneous

Granite

Granite (Phaneritic igneous rock)

Hardness: 6-7 on Mohs scale. Color: Gray, tan, and white with dark flecks. Luster: Vitreous to dull. Crystal structure: Macro-crystalline (phaneritic texture). Specific gravity: 2.63-2.75.

Hardness: 6-7 on Mohs scale
Color: Gray, tan, and white with dark flecks
Luster: Vitreous to dull

Identified April 7, 2026More igneous →

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Physical properties

Hardness: 6-7 on Mohs scale. Color: Gray, tan, and white with dark flecks. Luster: Vitreous to dull. Crystal structure: Macro-crystalline (phaneritic texture). Specific gravity: 2.63-2.75.

Formation & geological history

Formed from the slow crystallization of magma below Earth's surface (intrusive). Geological ages vary significantly from Precambrian to Cenozoic depending on the tectonic location.

Uses & applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, and monuments. Also used as crushed stone for road base and railroad ballast.

Geological facts

Granite makes up a large portion of the continental crust. Because it is so hard and durable, it has been used for some of the world's most famous structures, including the Great Pyramid of Giza (casing stones) and Mount Rushmore.

Field identification & locations

Identify in the field by its visible interlocking crystals of quartz (clear/gray), feldspar (white/pinkish), and mica (black/shiny). It is found in mountain ranges and continental shields worldwide.

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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