igneous

Granite (Pegmatitic)

Phaneritic Felsic Igneous Rock

Hardness: 6-7 (Mohs scale); Color: Mottled tan, pink, white, and grey with black flecks; Luster: Vitreous to pearly; Crystal structure: Macro-crystalline (phaneritic); Cleavage: Perfect on feldspar grains; Specific gravity: Approx. 2.65-2.75.

Hardness: 6-7 (Mohs scale)
Color: Mottled tan, pink, white, and grey with black flecks
Luster: Vitreous to pearly

Identified March 22, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow cooling of silica-rich magma deep within the Earth's crust (plutonic formation). This specimen shows large grain sizes characteristic of pegmatitic environments or slow-cooling continental crust environments ranging from the Precambrian to Cenezoic eras.

Uses & applications

Used widely in construction (countertops, tiles, paving), as industrial aggregate, and occasionally in lapidary for polished decorative stones.

Geological facts

Granite makes up much of the Earth's continental crust. Unlike basalt which covers ocean floors, granite is buoyant and 'floats' on the more dense mantle. The Mount Rushmore carvings are made of a similar granite composition.

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 common in mountainous regions and shield areas like Canada or Scandinavia. Collectors look for large shiny mica flakes or distinct pink potassium feldspar crystals.

Other igneous specimens

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

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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

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Magnetite

Magnetite (Fe3O4)

mineral