igneous

Granite

Phaneritic plutonic rock (SiO2 range 70-75%)

Hardness: 6-7 on Mohs scale. Color: Salt and pepper appearance with shades of white, gray, and black. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained), primarily composed of quartz, feldspar, and mica. Specific gravity: 2.63 to 2.75.

Hardness: 6-7 on Mohs scale
Luster: Vitreous to dull

Identified May 4, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow crystallization of magma below Earth's surface. These specific large rounded boulders (tors) are likely the result of spheroidal weathering and glacial transport during the last glacial period.

Uses & applications

Used extensively in construction for countertops, floor tiles, paving stones, and curbstones due to its durability. Also used for monuments and decorative architectural elements.

Geological facts

Granite makes up a large part of the continental crust. The boulders in the image show 'exfoliation' or 'sheeting' weathering, where outer layers of the rock flake off like an onion due to pressure release.

Field identification & locations

Identifiable by its visible interlocking crystals of quartz (clear/gray), feldspar (white/pink), and biotite or hornblende (black). Commonly found in mountain ranges and glaciated terrains.

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