Petrology is a discipline of geology that studies rocks, minerals and the processes that act on them. Scientists focus on the formation of rocks in this field of science.


Clay, an earthy material composed of very small particles of weathered rock. The particles are less than 0.00015 inch (0.004 mm) in diameter, much smaller than sand particles.

31-31 of 31
  • Travertine


    Travertine, a soft, compact or porous form of limestone. It is usually pale yellow, but may be dark yellow, brown, or streaked with light and dark bands because of impurities. See more »

31-31 of 31
More To Explore
Don't Miss