igneous

Granite Pebble

Felsic Intrusive Igneous Rock (composed of Quartz, Feldspar, and Mica)

Hardness: 6-7 on Mohs scale; Color: typically white, grey, or pink with dark speckles; Luster: dull to vitreous; Structure: phaneritic (visible crystals); Specific Gravity: 2.63 - 2.75

Hardness: 6-7 on Mohs scale
Color: typically white, grey, or pink with dark speckles
Luster: dull to vitreous

Identified March 28, 2026More igneous →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: typically white, grey, or pink with dark speckles; Luster: dull to vitreous; Structure: phaneritic (visible crystals); Specific Gravity: 2.63 - 2.75

Formation & geological history

Formed from the slow cooling and crystallization of magma deep within the Earth's crust. This specific specimen has been tumbled and rounded by water action over geological time.

Uses & applications

Used widely in construction (aggregate, countertops, flooring), decorative landscaping (as river rock), and road building due to its extreme durability and resistance to weathering.

Geological facts

Granite makes up a large portion of the Earth's continental crust. It is incredibly old; most continental granite dates back hundreds of millions or even billions of years.

Field identification & locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals. It is ubiquitous in riverbeds, glacial tills, and mountainous regions worldwide.

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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

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

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

mineral

Magnetite

Magnetite (Fe3O4)

mineral