igneous

Granite

Granite (Phaneritic Quartz-Feldspar Rock)

Hardness: 6-7 on Mohs scale. Color: Mottled gray, white, and translucent. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained visible crystals). Cleavage: Varies by mineral (feldspar has 2 directions). Specific gravity: 2.63 to 2.75.

Hardness: 6-7 on Mohs scale
Color: Mottled gray, white, and translucent
Luster: Vitreous to dull

Identified April 7, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow subterranean cooling and crystallization of magma. Usually associated with continental crust and formed over millions of years through intrusive volcanic processes.

Uses & applications

Used extensively in construction for countertops, floor tiles, paving stone, curbing, and monuments. Also used as crushed stone for road base and concrete aggregate.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Its name comes from the Latin word 'granum,' meaning a grain, in reference to its coarse-grained structure.

Field identification & locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of quartz, feldspar, and mica. It is extremely hard and cannot be scratched by a steel knife.

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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