igneous

Granite Pebble

Intrusive Felsic Igneous Rock (primarily SiO2 with Al2O3, K2O, Na2O)

Hardness: 6-7 (Mohs scale); Color: Mottled gray, pink, and white with black specks; Luster: Dull (weathered/tumbled) to vitreous (on fresh breaks); Structure: Phaneritic (coarse-grained) crystalline; Cleavage: None (fractures irregularly); Specific Gravity: 2.63 - 2.75

Hardness: 6-7 (Mohs scale)
Color: Mottled gray, pink, and white with black specks
Luster: Dull (weathered/tumbled) to vitreous (on fresh breaks)

Identified February 19, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow cooling and solidification of magma deep within the Earth's crust (plutonic formation). This specimen shows signs of mechanical weathering and transport by water (fluvial or glacial action), rounding its sharp edges into a smooth pebble shape.

Uses & applications

In bulk: used for construction aggregate, road base, and dimension stone (countertops). As a single pebble: primarily used for landscaping, garden decor, or as a pocket stone for amateur collectors.

Geological facts

Granite makes up the majority of the Earth's continental crust. The pink color in this specimen is likely due to potassium feldspar (orthoclase), while the white/gray translucent parts are quartz.

Field identification & locations

Identify by its 'salt and pepper' appearance and visible interlocking crystals. It is found globally across all continents, especially in mountain ranges and riverbeds downstream from igneous outcrops. Collectors can identify it by its inability to be scratched by a steel knife.

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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)

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Blue Apatite

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

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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Magnetite

Magnetite (Fe3O4)

mineral