igneous

Granite

Phaneritic Felsic Igneous Rock

Hardness: 6-7 Mohs; Color: Gray with salt-and-pepper flecks (white/gray quartz/feldspar and black biotite/hornblende); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained visible crystals); Cleavage: Distinct in feldspars, none in quartz.

Hardness: 6-7 Mohs
Luster: Vitreous to dull

Identified April 5, 2026More igneous →

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Physical properties

Formation & geological history

Formed through the slow crystallization of magma below the Earth's surface (intrusive). This specimen shows a coarse-grained texture indicating long cooling times in the continental crust.

Uses & applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, and monuments due to its durability and resistance to weathering.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Unlike oceanic crust which is mostly basalt, the continents are 'buoyant' because they are made of less-dense granitic rocks.

Field identification & locations

Identify by looking for interlocked crystals of quartz (glassy gray/white) and feldspar (blocky opaque white/pink). It will scratch glass easily. Common in mountain ranges and glacial deposits.

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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