Nh.cvl.engineer@gmail.com

Boulders

In geology , a boulder is a rock with grain size of

usually no less than 30 centimeters (1 ft) diameter

CobblesA cobble is a cast of rock with a particle size of 7.6

centimeter (3 in) to 30.5 centimeters (1ft)

GravelsA gravels is composed of unconsolidated rock fragments that have a general size of 4.75mm to 76mm ( 3 in )

Coarse Gravels Fine Gravels

20mm (3/4’’) to 76mm (3in) 4.75mm to 20mm (3/4’’)

Types Of Gravels

Bank gravel:naturally deposited gravel intermixed with sand or clay

found in and next to rivers and streams. Also known as "Bank run" and

"River run".

Bench gravel: A bed of gravel located on the side of a valley above

the present stream bottom, indicating the former location of the stream bed when it was at a higher level.

Creek rock:This is generally rounded, semi-polished stones,

potentially of a wide range of types, that are dredged or scooped from river beds and creek beds. It is also often used as concrete aggregate and less often as a paving surface.

Crushed stone:Is rock crushed and graded by screens then mixed to a

blend of stones and fines. It is widely used in as a surfacing for roads and driveways, sometimes with tar applied over it. Crushed stone may be made from granite, limestone, dolomite, and other rocks. Also known as "crusher run", DGA (Dense Grade Aggregate) QP (Quarry Process), and shoulder stone

Lag gravel: A surface accumulation of coarse gravel produced by the

removal of finer particles.

Pay gravel: Also known as "pay dirt"; a nickname for gravel with a high

concentration of gold and other precious metals. The metals are recovered through gold panning.

Pea gravel: Gravel that consists of small, rounded stones used in concrete

surfaces. Also used for walkways, driveways and as a substrate in home aquariums.

Piedmont gravel: A coarse gravel carried down from high places by

mountain streams and deposited on relatively flat ground, where the water runs more slowly.

Plateau gravel: A layer of gravel on a plateau or other region above

the height at which stream-terrace gravel is usually found.

Sand

Sand is a naturally occurring granular material composed of

finely divided rock and mineral particles. It is defined by size,

being finer than gravel and coarser than silt having size of

( 4.75mm to 0.075mm ).

Coarse Sand

Passing ASTM sieve No.4 and retained on ASTM sieve

No. 10

Passing ASTM sieve No.10 and retained on ASTM

sieve No. 40

( 2mm to 4.75mm )

Medium Sand

Fine Sand

Passing ASTM sieve No.40 and retained on ASTM

sieve No. 200

( 0.425mm to 2mm )

( 0.075mm to 0.425mm )

SiltSilt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as sediment mixed in suspension with water (also known as a suspended load) in a body of water such as a river. It may also exist as soil deposited at the bottom of a water body

( 0.005mm to 0.075mm )

ClayClay is a fine-grained soil that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosillicate minerals containing variable amounts of water trapped in the mineral structure

( >0.005mm )

Colloids ( >0.001mm )

A colloid is a substance in which microscopically dispersed insoluble particles are suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid

Thanks'