Defining Rocks

We should confess that the term Rocks is somewhat problematic. Yet this is arguably one of those areas where most people can have a similar understanding despite the ambiguity in our use of the term. We are trying to capture here the key elements of our planet's (any hard planet's?) surface, and thus describe both biotic and abiotic phenomena. A better term might be "Earth Materials," but people might have a harder time grasping what that means. Or we could use "Components of the Lithosphere," but with a similar challenge. Suggestions are welcome.