igneous

Granite Pebble (Pink Granite)

Phaneritic Igneous Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Hardness: 6-7 Mohs; Color: Mottled pink/orange, gray, and black; Luster: Dull to vitreous (glassy) depending on crystal faces; Crystal Structure: Phaneritic (coarse-grained visible crystals); Cleavage: Irregular fracture overall, though feldspar grains show perfect cleavage planes.

Hardness: 6-7 Mohs
Color: Mottled pink/orange, gray, and black
Luster: Dull to vitreous (glassy) depending on crystal faces

Identified March 24, 2026More igneous →

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Physical properties

Formation & geological history

Formed through the slow crystallization of magma below Earth's surface (intrusive). This specimen shows rounded edges indicating it was likely weathered and transported by water in a river or glacial environment. Geological age can range from millions to billions of years (Precambrian to Cenozoic).

Uses & applications

Used extensively in construction (crushed stone), decorative architecture (countertops, monuments), and as abrasive material. High-quality tumbled pieces are common in rock collections.

Geological facts

Granite makes up the majority of the Earth's continental crust. Its pink color is caused by an abundance of potassium feldspar (orthoclase).

Field identification & locations

Identify in the field by its 'salt and pepper' or multicrystalline mottled appearance and extreme hardness (will scratch glass). Commonly found in mountain ranges, glacial till, and riverbeds globally.

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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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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

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

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Magnetite

Magnetite (Fe3O4)

mineral