River Rock Composition

The most common river rocks used in landscaping and decorative construction are made of granite.

River rock composition.

River composition due to evaporation of rock dominated water. Grains of sand that can be feldspar or quartz the amount of other minerals such as mica depend on how much weathering has occurred. In this situation the composition evolves downstream from a rock weathering type at headwaters to a more concentrated and sodium rich water nearer the mouth. Costs vary considerably but river rocks are typically sold by the pound or the ton.

Pebble tools are among the earliest known man made artifacts dating. A pebble is a clast of rock with a particle size of 4 to 64 millimetres based on the krumbein phi scale of sedimentology pebbles are generally considered larger than granules 2 to 4 millimetres diameter and smaller than cobbles 64 to 256 millimetres diameter. Most rocks are composed of minerals. Continued evaporation precipitates caco 3 and increases the na na ca ratio.

Minerals are defined by geologists as naturally occurring inorganic solids that have a crystalline structure and a distinct chemical composition. Of course the minerals found in the earth s rocks are produced by a variety of different arrangements of chemical elements. River rocks come in a variety of sizes ranging from 1 inch up to several inches across. The resulting sand is deposited on beaches along floodplains or in deltas.

A rock made predominantly of pebbles is termed a conglomerate. Granite belongs to the intrusive category of igneous rock which means it formed below the earth s surface as magma slowly cooled and crystallized.