igneous
Granite or Granitic Gneiss River Rock
Granite
AI-generated identification · may be incorrectHardness of 6-7 on Mohs scale. Mottled appearance with distinct crystalline grains of quartz, feldspar, and darker minerals (like biotite or hornblende). Color is typically yellowish-brown to greenish-gray in this wet specimen. Smooth and rounded from water erosion.
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Physical properties
Hardness of 6-7 on Mohs scale. Mottled appearance with distinct crystalline grains of quartz, feldspar, and darker minerals (like biotite or hornblende). Color is typically yellowish-brown to greenish-gray in this wet specimen. Smooth and rounded from water erosion.
Formation & geological history
Formed from slow cooling of magma deep underground. The rounded shape indicates it has been transported and smoothed by water action in a river or glacial environment over thousands to millions of years.
Uses & applications
Commonly used in landscaping as decorative river rock or aggregate. Larger unweathered deposits are quarried for building stone, countertops, and monuments.
Geological facts
River rocks are often found in riverbeds, beaches, or glacial till. The wet surface enhances the color and visibility of the individual mineral grains.
Field identification & locations
Identify by the speckled, crystalline texture and extreme hardness. Look for the distinct grains of different minerals. Very common in riverbeds and glacial deposits worldwide.
