What order are rocks in from smallest to biggest?

Rocks are generally classified into three main categories based on their size: sediments, which are the smallest particles, followed by gravel, and then boulders, which are the largest. Sediments can include silt and clay, while gravel consists of larger fragments. Boulders are typically defined as rocks larger than 10 inches in diameter. In summary, the order from smallest to biggest is sediments, gravel, and boulders.