igneous
Polished granite pebble
Granite, chiefly quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse-grained, speckled pink-gray and black stone with a polished, glassy-to-waxy luster; quartz hardness ~7, feldspar ~6, and typical granite specific gravity 2.63–2.75. The rounded shape and shine indicate water-worn and/or mechanically polished material.
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Physical properties
Coarse-grained, speckled pink-gray and black stone with a polished, glassy-to-waxy luster; quartz hardness ~7, feldspar ~6, and typical granite specific gravity 2.63–2.75. The rounded shape and shine indicate water-worn and/or mechanically polished material.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the continental crust, commonly during Precambrian through Phanerozoic mountain-building events. The visible specimen was likely weathered from an outcrop and tumbled or polished.
Uses & applications
Used extensively for countertops, monuments, building stone, aggregate, landscaping, and decorative or worry stones; this small piece has minimal commercial value.
Geological facts
The pale crystals are likely feldspar and quartz, while dark patches may be biotite mica or hornblende. Granite’s visible interlocking crystals distinguish it from fine-grained rhyolite.
Field identification & locations
Identify it by its interlocking light crystals, dark minerals, lack of layering, and inability to scratch quartz with ordinary steel. Common worldwide, especially in exposed continental shields and mountain belts.
