igneous

Granite (Polished Pebble)

Phaneritic Plutonic Rock (primarily Orthoclase and Quartz)

Hardness: 6-7 Mohs; Color: Pinkish-brown with black and grey speckles; Luster: Vitreous when polished; Crystal Structure: Coarse-grained phaneritic; Cleavage: None (fractures); Specific Gravity: 2.63-2.75

Hardness: 6-7 Mohs
Color: Pinkish-brown with black and grey speckles
Luster: Vitreous when polished

Identified June 3, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow cooling of magma deep beneath the Earth's surface (plutonic). This specimen has been rounded and polished by either river action or a rock tumbler.

Uses & applications

Primarily used in construction (countertops, monuments) and as decorative landscape gravel or polished pocket stones.

Geological facts

Granite makes up a large portion of the Earth's continental crust. The pink color in this specimen is due to the presence of potassium feldspar (orthoclase).

Field identification & locations

Identify by its interlocking crystalline texture and lack of layering. Commonly found in mountainous regions or as river pebbles. Collectors look for unique mineral inclusions like mica or tourmaline.

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Granite

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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