In addition to adding color, texture ... gravel are among the most popular types of landscaping rocks, followed by crushed granite, boulders, river rock, gravel, brick chips, marble rocks ...

"River rock gray is a beautiful, unique color that is becoming more and more popular for fences," says Spinelli. "This color has a natural look that can really complement your landscape.

A new study in Chile shows how small differences in rock type can drive large differences in erosion, vegetation, and river networks, illuminating the role of mineralogy in shaping landscapes.