Pebbles and Gravel
Scientific Name: N/A
Category: rock
Brief Description
A dense collection of small, rounded rock fragments and stones, commonly found in riverbeds, beaches, or used as landscaping aggregate.
Characteristics
Composed of small, weathered mineral and rock fragments typically ranging from 2 mm to 64 mm in diameter. They often exhibit smooth, rounded edges due to water or wind abrasion.
Habitat
Riverbanks, stream beds, lake shores, beaches, and glacial outwash plains, as well as human-made pathways and landscaping beds.
When to Find It
N/A
Conservation Status
N/A
Ecological Role
Provides micro-habitats for various macroinvertebrates and spawning beds for freshwater fish such as salmon and trout. Helps with soil drainage and erosion control.
Easily Confused With
Crushed stone; crushed stone features sharp, angular edges from mechanical crushing, whereas natural pebbles and gravel are smooth and rounded.
Observation Tips
Look along river edges and dry washes to observe how water action sorts and rounds rock fragments.
Interesting Facts
Pebbles are classified by geologists using the Wentworth scale, where particle sizes between 4 mm and 64 mm are specifically termed pebbles.