Gravel 
Small to large stones. Gravel is a material with a diameter between 2 and 64mm. It is categorised using the Udden-Wentworth scale as granular gravel (2 to 4mm diameter) and pebble gravel (4 to 64mm diameter).
Gravel
Small to large stones. Gravel is a material with a diameter between 2 and 64mm. It is categorised using the Udden-Wentworth scale as granular gravel (2 to 4mm diameter) and pebble gravel (4 to 64mm diameter).