Gravel
Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is an important commercial product with several purposes. Almost half of all gravel production is used as aggregate for concrete.
Commonly,Gravel is containing quartz, limestone, granite, quartzite, and sandstone. But depending the Location it can contain different materials:
Mountainous & Volcanic AreasInside the rock: High amounts of granite, basalt, obsidian, or pumice.Special traits: This gravel is fresh and young, meaning it is highly angular and sharp. Inside volcanic gravel (like lava rock), you will find millions of gas bubbles (vesicles), making the stones incredibly lightweight.
Placer" Locations (Gold Country)Inside the mix: In specific historic river valleys or glacial deposits, gravel naturally contains heavy precious metals.Special traits: You can find flakes of gold, platinum, diamonds, or heavy iron minerals (magnetite) wedged in between the gravel stones.
Glacial Regions (Glacial Till)Inside the rock: An unpredictable, chaotic mix. Because glaciers act like giant bulldozers, they carry rocks from hundreds of miles away. You might find metamorphic rocks mixed directly with limestone.Special traits: The gravel inside is poorly sorted (massive boulders mixed with tiny pebbles) and features heavily scratched surfaces (striations) from being dragged under heavy ice.
Beaches & Coastal AreasInside the rock: A heavy mix of shale, sandstone, and local coastal bedrock.Special traits: Sea gravel often includes fragmented seashells, coral bits, and high salt deposits trapped in the outer pores of the stones.
Riverbeds & Streams (River Rock)Inside the rock: Mostly heavy-duty minerals like quartz and chert. Fragile rocks break down quickly in water, leaving only the hardest elements behind.Special traits: The stones are perfectly smooth and rounded from tumbling against each other.Surrounding mix: Known as "bank run gravel," it is naturally packed with river silt, fine sand, and organic clay.
Urban Areas & Quarries (Man-Made Gravel)Inside the rock: Usually 100% uniform limestone, dolomite, or granite mechanically blasted from the earth.Special traits: If it is "recycled gravel," it will contain crushed pieces of demolition concrete, old bricks, glass shards, and bits of asphalt.
Dependencies
See also
References
| This article uses material from the Wikipedia article Gravel, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors). | 
|