Multiple choice

Which of the following type of rocks has the smallest size particles?

  1. Clay

  2. Silt

  3. Sand

  4. Gravel

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Clay has the smallest particle size of all soil types, with particles less than 0.002mm in diameter. Particle size increases in the order: clay (<0.002mm) < silt (0.002-0.05mm) < sand (0.05-2mm) < gravel (>2mm). This gives clay its smooth texture when wet.