igneous

Granite Pebble

Granite

Hardness: 6-7 on Mohs scale; Color: Mottled cream, tan, and grey; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarsegrained) with visible crystals of quartz, feldspar, and mica.

Hardness: 6-7 on Mohs scale
Color: Mottled cream, tan, and grey
Luster: Dull to vitreous

Identified May 7, 2026More igneous →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Mottled cream, tan, and grey; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarsegrained) with visible crystals of quartz, feldspar, and mica.

Formation & geological history

Formed through the slow crystallization of magma below Earth's surface. This specimen appears to be a water-worn pebble, meaning it was eroded and smoothed by stream or river action long after the original intrusion cooled.

Uses & applications

Granite is widely used in construction as dimension stone, for countertops, and as crushed stone for road base. Small pebbles have little industrial use but are common in landscaping.

Geological facts

Granite makes up a large portion of the Earth's continental crust. Because it is highly resistant to weathering, granite pebbles can survive long transport distances in rivers and glacial deposits.

Field identification & locations

Identify by its interlocking 'salt and pepper' crystalline texture and its extreme hardness (cannot be scratched by a steel knife). Commonly found in riverbeds, glaciated regions, and near mountain ranges.

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mineral

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