Pebble in the context of "Beach"

At a flat coast or flat shoreline, the land descends gradually into the sea. Flat coasts can be formed either as a result of the sea advancing into gently sloping terrain or through the abrasion of loose rock. They may be basically divided into two parallel strips: the shoreface and the beach.

Flat coasts consist of loose material such as sand and gravel. Wind transports finer grains of sand inland over the dunes. The sea washes pebbles and sand away from the coast and dumps it at other locations.

The mosaics of Delos are a significant body of ancient Greek mosaic art. Most of the surviving mosaics from Delos, Greece, an island in the Cyclades, date to the last half of the 2nd century BC and early 1st century BC, during the Hellenistic period and beginning of the Roman period of Greece. Hellenistic mosaics were no longer produced after roughly 69 BC, due to warfare with the Kingdom of Pontus and the subsequently abrupt decline of the island's population and position as a major trading center. Among Hellenistic Greek archaeological sites, Delos contains one of the highest concentrations of surviving mosaic artworks. Approximately half of all surviving tessellated Greek mosaics from the Hellenistic period come from Delos.

The paved walkways of Delos range from simple pebble or chip-pavement constructions to elaborate mosaic floors composed of tesserae. Most motifs contain simple geometric patterns, while only a handful utilize the opus tessellatum and opus vermiculatum techniques to create lucid, naturalistic, and richly colored scenes and figures. Mosaics have been found in places of worship, public buildings, and private homes, the latter usually containing either an irregular-shaped floor plan or peristyle central courtyard.

Gravel (/ˈɡrævəl/) is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentary and erosive geological processes; it is also produced in large quantities commercially as crushed stone.

Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2–4 mm or 0.079–0.157 in) and pebble gravel (4–64 mm or 0.2–2.5 in). ISO 14688 grades gravels as fine, medium, and coarse, with ranges 2–6.3 mm (0.079–0.248 in) for fine and 20–63 mm (0.79–2.48 in) for coarse. One cubic metre of gravel typically weighs about 1,800 kg (4,000 lb), or one cubic yard weighs about 3,000 lb (1,400 kg).

A desert pavement, also called reg (in western Sahara), serir (in eastern Sahara), gibber (in Australia), or saï (in central Asia) is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size. They typically top alluvial fans. Desert varnish collects on the exposed surface rocks over time.

Geologists debate the mechanics of pavement formation and their age.

Substrate is the earthy material that forms or collects at the bottom of an aquatic habitat. It is made of sediments that may consist of:

• Silt – A loose, granular material with mineral particles 0.5 mm or less in diameter.
• Clay – A smooth, fine-grained material made of fine particles of hydrous aluminium phyllosilicate minerals (such as kaolinite).
• Mud – A mixture of water with silt, clay, or loam.
• Sand – Mineral particles between 0.06 and 2 mm in diameter.
• Granule – Between 2 and 4 mm in diameter.
• Pebble – Between 4 – 64 mm in diameter.
• Cobble – between 6.4 and 25.6 cm in diameter
• Boulder – more than 25.6 cm in diameter.
• Other, assorted organic matter, detritus.

Stream substrate can affect the life found within the stream habitat. Muddy streams generally have more sediment in the water, reducing clarity. Clarity is one guide to stream health.

A shingle beach, also known as either a cobble beach or gravel beach, is a commonly narrow beach that is composed of coarse, loose, well-rounded, and waterworn gravel, called shingle. The gravel (shingle) typically consists of smooth, spheroidal to flattened, pebbles, cobbles, and sometimes small boulders, generally in the 2 to 20 centimetres (0.8 to 7.9 in) size range. Shingle beaches typically have a steep slope on both their landward and seaward sides. Shingle beaches form in wave-dominated locations where resistant bedrock cliffs provide gravel-sized rock debris. They are also found in high latitudes and temperate shores where the erosion of Quaternary glacial deposits provide gravel-size rock fragments. This term is most widely used in Great Britain.

While this type of beach is most commonly found in Europe, examples are also found in Bahrain, North America, and a number of other world regions, such as the west coast of New Zealand's South Island, where they are associated with the shingle fans of braided rivers. Though created at shorelines, post-glacial rebound can raise shingle beaches as high as 200 metres (660 ft) above sea level, as on the High Coast in Sweden.

A cobble (also sometimes called a cobblestone) is a clast of rock defined on the Udden–Wentworth scale as having a particle size of 64–256 millimeters (2.5–10.1 in), larger than a pebble and smaller than a boulder. Other scales define a cobble's size differently. A rock made predominantly of cobbles is termed a conglomerate. Cobblestone is a building material based on cobbles.